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  • HPH386: The potential of mycelium-based composites – with Joshua English

    HPH386: The potential of mycelium-based composites – with Joshua English

    Joshua English, co-founder of Okom wrks labs shares his journey into the creation of a mycelium-based composite material, which has structural and load-bearing properties.

    Interview with Joshua English

    Joshua English, co-founder of Okom wrks labs describes himself as a jack of all trades with a lifelong obsession with fungi. Although he did an arts degree, he realised he loved working with numbers and so spent his early professional life in database programming. After 18 years doing data analysis and data visualisations for healthcare he started to miss the physical world. He then took a degree in Interior Architecture and Design, with an emphasis on industrial design which led to a hyper focus on materiality. A long-time carpenter, with a love of metal and concrete and the knowledge that those materials were not great for the environment, he wanted to try to find the most sustainable way to build things. When a friend introduced him to mycelium-based composites about six years ago, he took a deep dive into the subject.

    Could he make a chair using mycelium-based composites that people could sit on?

    In his research he came across pictures of chairs made from mycelium-based composites, but nobody was sitting on them. Could he be the first designer to make a chair that a human could sit upon? He spent six months gathering information on the technology with a plan to spend two years researching how to make mycelium-based composites stronger. He ended up finding a solution much quicker through a random application of materials left over from his first set of experiments. He then had to reverse engineer from this “mistake” to work out what had happened. It took a few years to patent this process and they are now looking to patent the material itself.

    Mycelium are fungi and not to be confused with plants

    Mycelium is fungi, which is in its own kingdom and not to be confused with the plant kingdom. Joshua explains that where animals engulf their food and plants photosynthesize, fungi absorb their food, so their whole lifestyle is centred around surface area. We think of mushrooms as fungi, but they are just the fruiting body, the mycelium is by far the vast majority of the organism. He compares it to an ant colony, where the individual ants are like the hyphal strands of the mycelium. A mycelium will have billions of hyphae that branch out to explore their environment. They provide a large surface area and exude enzymes to absorb their preferred food source. To do this the hyphal strands need to be incredibly strong, durable, and multi-use as well. Joshua is exploiting the capability of the fungus to create an adhesive to use as part of the matrix of a composite material. Not all fungi have the capabilities to create strong mycelium-based composites, and so far, mycologists have found that fungi that grow on trees are particularly well suited for this.

    This technology is still in its infancy

    The technology goes back to the early 2000s, but it has grown and developed in the last 25 years. Philip Ross, an art major at Stanford and a lifelong mycophile started to develop processes to make things out of mycelial colonies about 20 years ago. He then used mycelium blocks to create striking artworks and published his findings, which people started to notice. Some engineering students in New York, then developed a business model to use this technology to make a foam packaging replacement. They tried to commercialise it about 13-15 years ago. When researchers started to look at the key qualities of the mycelium-based materials they were impressed with its fire resistance and sound attenuation, but it was not so good structurally or when it came to water absorption. This led to them being relegated to insulating panels or decorative wall sound mitigation panels.

    “And then, you have a guy like me who makes a mistake in the lab and then finds this way to make what seemed to me to be structurally sound materials.”

    Turning it into a business is a huge challenge

    Joshua believes that a 5 -10 year time frame is needed to go from the research phase to a commercial product. In his experience Venture Capital investors want more of a 2 year turnaround, so there is a mismatch here that needs to be overcome. Because it’s such a new technology there is a lot of siloing happening along with a push to early commercialisation. There is also a big rush to patent the materials, because you don’t want to be overtaken, but this has all led to a stifling of the technology and people making wild claims. Joshua is clear that any claims need to be backed up with data and currently there are no standards for how we measure and create these things. Joshua thinks that for this technology to move forward governments need to subsidise it and universities need to continue the research. It needs targeted attention and standardisation of methods, but none of this is going to happen without funding. Joshua believes the capabilities for mycelium composites are endless, as endless as the kingdom of fungi.

    The mycelium-based composites are grown in the lab

    Joshua explains that you need at least a food grade level of facility to grow the fungal starter culture, very different to a standard sawmill making SIPs. But one of the amazing things about this technology is you can start from a single fungal spore and grow enough material in about 90 days for several houses. During the process, the spore starts in a petri dish, and you grow it, adding a bit of material at a time. You can increase the amount of material you add as it builds up, whilst making sure the fungus isn’t getting too old, because its life cycle can be rapid. Joshua grows the material in the open air and doesn’t use rigid moulds. A remarkable part of the process is that it takes five days to grow, whether it’s one metre or ten metres, it’s the same amount of time. During that time, it fully colonises the substrate and forms a fungal skin around the outside of the material, which is tough and durable. At the end of the process, you dry it, to kill the fungus, as you don’t want the fungus to continue to digest the material. It is the drying process that gives it the rigidity and strength.

    The Hy-Fi tower

    Experimental projects demonstrate potential for the future

    Joshua completed a non-structural project in New York City two years ago using their mycelium-based composites. The second half of that project was to include the manufacturing of chairs, but difficulties in finding the right facilities to dry the material brought things to a halt. The Hy-Fi tower at PS1 in New York City is a well known example of using mycelium bricks in a large structure. However, the tower was built of timber and the bricks are just infill. A man in Ohio has used edible mushroom mycelium blocks, compressed at a 20:1 ratio to make strong materials. Joshua is trying to develop a different process, which tests how far the fungus can go itself, so not using any industrial compression to bring strength. He is also currently limited in the size he can make, at 3m long by 300mm wide.

    Okom wrks labs could also look at creating a two by four wood replacement product but at this stage it would not be as strong as wood. However, they are finding that if they grow several parts together, at the same time and cross layer them, they can build an incredibly strong 2 feet by 2 feet SIP wall section. In their trial seven parts were all adhered together by the mycelium itself. There was no glue involved and although they didn’t get to do a compression test it did seem like there was a synergistic effect by growing them together in this way. There are more collaborations brewing and the potential for space technologies for drying that would make it possible for them to restart building SIP wall sections.

    Working at full scale they could compete with standard SIP wall panels

    Very early on Chris Magwood suggested concentrating on structural insulated panels (SIPs) and Joshua believes that if they could work at full scale, they could produce mycelium-based composite SIPs at a competitive price. Over time, they could make that difference even greater.

    Mycelium-based composites are already being used outside construction

    Mogu in Italy has been creating decorative sound attenuating wall panels for a long time now, which has kept the material in the zeitgeist. There have been several attempts at creating businesses with foam packaging, but it’s been rather difficult to commercialise the products overall. Le Corbusier regarded chairs as small pieces of architecture and as Joshua is also infatuated with chair design, he thinks a fully mycelium-based composite chair could be the way to show people what is possible. It would show the industry that it can be done commercially, and consumers that you can put these things in your house. They’re not going to grow weird things off the sides, and they will have some heirloom quality to them!

    It is healthy for people with allergies to mushrooms

    In Joshua’s process the fungus is killed at a certain point and never reaches the fruiting body stage, which means spores are not produced. It’s usually the spores that people have sensitivities to, so it’s therefore completely healthy. The other issue is that most mycelium-based composites are incredibly hygroscopic, which means they will take up a lot of water. Other moulds or anything else, could start to colonise the material in a wet state, so you need to be able to stave off that moisture. This would be about protecting it from the elements, like you do with timber, so you would then have a system with longevity. Joshua admits its early days and hypothetical, but from his own research he thinks it is doable, and it is safe.

    He explains that whilst foam-like mycelium-based composites typically have a water uptake of 200 to 300%, their material is far more dense, with a water uptake of around 25 to 45%. That’s a big leap in the right direction with more improvements possible through improving the fungal skin or adding natural products like beeswax. His goal is to avoid any kind of petroleum based products, if possible, but has accepted that using an epoxy resin covering may be a good way to get things started.  

    Hemp is the Joshua’s preferred substrate for growing the mycelium

    Joshua is developing a composite material, which we might compare to the first earth bricks that included straw to add strength to the mud. He is using hemp as the substrate for the mycelium to grow on as it is a strong material and is “tasty” to the fungus they’re using. The fungus serves as an adhesive that binds everything together, so you’re using these two different materials to create something like a brick. He then adds in the textile reinforcement phase that provides even more strength and improves the compressive strength by orders of magnitude over the foam-like materials and other types of mycelium-based composites. That textile reinforcement phase is notoriously difficult as it needs to be clean enough to grow without it getting contaminated before the end of the grow process.

    We need to re-imagine how we use materials

    Even though Joshua’s data is showing increased strength in the material it is still only just over one megapascal in compressive strength. This is not great from an engineer’s perspective, so can we think differently about how we build? He is thinking about modular building rather than lots of concrete and brute strength. Instead use geometry and genius engineering to build lighter, stronger structures. Anything that makes steel lighter and stronger from a geometry standpoint, would also work with their material. There is also work to optimise the way that the fungus grows and possibly some genetic changes to the fungus that would enhance certain qualities. Machine learning can help with this process as there are so many variables to consider. People are now starting of pool resources, with Phil Ross, setting up a nonprofit, called Open Fung. This is to create baselines for researchers, so people are not starting from scratch each time and can hopefully go further and faster on the engineering side.

    The potential applications are as diverse as the kingdom of fungi

    Joshua believes that the potential applications for mycelium-based composites are as diverse as the kingdom of fungi, but the material needs to match the job it’s meant to do whether that’s in industrial design or architecture. It’s also important not to oversell the capabilities. Whilst patenting is important to gain investment, there is a need for more collaboration in the field, and that is Joshua’s request to the mycologists and engineers currently exploring these ideas.

    “I think the future is wide open as we are at the nascent stages of understanding how fungal mycelium-based composites come together.”

    Find out more

    Okom wrks labs

    Follow Joshua English on LinkedIn

    Transcript

    Download a transcript of this episode.

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  • HPH333 : What is the One Planet Development scheme? – with Brendan and Ludka Powell

    HPH333 : What is the One Planet Development scheme? – with Brendan and Ludka Powell

    Ludka and Brendan Powell explain the Welsh ‘One Planet Development’ scheme and how it led them to building an off-grid, straw panel Passivhaus.

    Interview with Ludka and Brendan Powell

    Ludka and Brendan Powell are self-builders with an interest in sustainability. They began to question whether the way they were living was the best way to live, and could they find an alternative way that connected them with their surroundings more.

    One Planet Developments (OPDs) are a Welsh Government initiative

    By granting planning permission to build on agricultural land, the scheme aims to get people back to living and working in the countryside, growing food locally. A One Planet Development means living a sustainable lifestyle, with the lowest carbon footprint you can manage, producing your own power and dealing with your own waste.

    A key goal is to ultimately produce 60% of your own food on site, as part of meeting your ‘basic needs’ within five years. Basic needs include council tax, running a car, phone bills, and the food that can’t be produced on site.

    Meeting the five-year goal of an OPD requires a business plan

    It’s very difficult to quantify how you’ll be doing after five years, so the scheme requires that you have a business plan and produce an annual progress report. At the end of five years, if you haven’t quite reached your targets but are on the right track then you produce a second business plan to show what will happen next to reach the goal.

    At the halfway stage of their own five-year timeframe, Ludka and Brendan have found it to be a big ask but they are on schedule. Anything they overproduce helps with their income. For example, they sell salad to local shops and make sauerkraut from cabbages, alongside producing honey.

    One planet thinking is long-term, holistic thinking

    An important part of the OPD is that Ludka and Brendan are trying to regenerate the land by transitioning from monoculture. They are trying to bring biodiversity, grow crops alongside keeping animals, and farm organically.

    They have planted an orchard and an extra acre of woodland to attract wildlife, and keep bees to help with pollination. It’s about working with nature rather than being geared towards profit, and the real benefits might not be seen for a decade. It is about attaching other values than just a monetary value to things.

    The one planet way of life is sustainable

    Doing everything in five years is a massive challenge, and Ludka and Brendan acknowledge they might not be doing everything right straight away. However, they are confident that after ten years everything will be perfectly fine.

    It is sustainable in the way they are putting a lot of energy into the land, but getting so much back from it in terms of fulfillment. As well as seeing the productivity of the land improve, they are also seeing change in terms of people being willing to go out of their way to buy produce from them rather than from the supermarket.

    OPDs attract determined people

    Building a house is often the biggest thing anybody undertakes in their life, so doing that alongside regenerating a piece of land and building a sustainable business has been intense for Ludka and Brendan. Taking on a self build is not the only route for those undertaking OPDs and some opt to build tiny houses using the Caravan Act. However, for Brendan and Ludka it was an opportunity to create more space for family life and have a hardy kitchen for processing their crops.

    People who do OPDs tend to really care about the planet’s future, and recognise that we can’t carry on living as we are. There has to be different way.

    One Planet Development Policy can evolve

    OPDs are an experiment to try and take society in a better direction. There are not many of them, but the existing developments have been successful in feeding people locally and improving the ecology of the land.

    Not everything in the scheme is perfect but it gets reviewed and recommendations for improvements have been made.

    Being off-grid is not mandatory for OPDs

    Ludka and Brendan have no utilities coming to site. Their water comes from a borehole, and electricity is generated from solar PV. Waste is dealt with through a composting toilet and reedbed system.

    Anyone creating an OPD can choose the most sustainable solutions to suit their site. Using mains water is not really a problem, but one of the principles of the initiative is dealing with your own waste.

    Off-grid living is more mindful

    The project is labour intensive, even more so because Ludka and Brendan also have three children. But it also makes them more self-reliant and aware of their actions. They can’t just switch on the electric oven at nine o’clock at night in December because they want to heat something up.

    Their children are growing up with the same values. For example, if they have a bag of sweets, that creates plastic waste. What will happen with the waste? They don’t have a throwaway culture.

    That extends to the household waste and their sophisticated composting system. In a ‘normal’ house it’s really easy to just flush the toilet and not think about where the waste is going. Ludka and Brendan have to constantly think about what they’re doing with their waste and keep an eye on everything.

    A Passivhaus was the natural choice – in more ways than one

    Having lived in a cold and damp house that was never truly comfortable, Ludka and Brendan knew they wanted a house that was going to cost very little to run and not need lots of heating.

    Making it as well-insulated as possible meant they wouldn’t be spending time on the land sourcing firewood to burn. In their temporary accommodation they were burning wood all day and half of the night in winter; now they only need enough to make dinner on the cooker, with enough residual heat to heat water.

    One Planet living means using sustainable and natural materials where possible, and minimising your carbon footprint – so a timber-framed Passivhaus with straw bale insulation minimised both operational energy and embodied emissions.

    The straw bale system performs as promised

    Getting a straw bale house to Passivhaus standard is difficult, but the EcoCocon system has delivered what was promised. The addition of wood fibre insulation around the outside brings the insulation up to the required level. Once the system was in place, it was simply a matter of following all of the normal Passivhaus principles to achieve the necessary airtightness and so on.

    The wraparound veranda helps the house stay cool in summer

    A veranda provides shading that is at just the right angle to maximise passive heating year-round without summer overheating. The veranda is also somewhere to live outside in the Welsh climate.

    In the summer, the windows never need to be opened because Ludka and Brendan never feel they need to do so. And in autumn, they were amazed at how warm the house continued to be when the air temperature outside started to cool.

    During winter, the sun shines through the windows and warms the polished concrete floor, which helps to keep the house warm until the following day. And the floor was a practical choice too, because it’s easier to sweep when bringing in mud from the fields.

    Making careful material choices throughout

    Yet another advantage of the concrete floor is that Ludka and Brendan didn’t have to buy carpets or wood flooring.

    Keeping within the One Planet principles, they have used recycled materials wherever possible – including recycled foam glass in the floor, and cellulose (recycled newspaper) in the roof. Sourcing local materials was also important. All of the cladding was made within ten miles of the site, and all of the architraves are made of local ash.

    Inside, they’ve used a kitchen recycled from another house, and done similar with bathroom and utility room fittings – all of which helps to save money too.

    MVHR can work in off-grid houses

    Ludka and Brendan’s MVHR system uses very little power, around 20 to 30 Watts all the time. On a few days in December and January, when there’s little light, they’ll only run the MVHR in the day. There’s been no detrimental effect from that.

    They run two inverters, having fitted a smaller one that can cope with demand from the MVHR, lights and laptops. The larger inverter is still needed for appliances, but it was using over two kilowatt hours per day by itself. Using the smaller inverter means they can now more easily survive the winter without getting short on power.

    Running businesses together helped with teamwork

    Both Ludka and Brendan were very engaged with the project, rather than one of them leading. Both have been involved right from the ground up, but they would feel strongly about different things. The important thing was to ask each other’s opinion.

    Through running businesses together they have learned to delegate, so Ludka wouldn’t deal with carpentry but did do a lot of wet processes like clay plastering. Plasterboarding and decorating ceilings were two jobs in particular that provided to be long and laborious!

    Creating a One Planet Development requires strong-mindedness

    You have to be resourceful and dedicated. Never underestimate how much there is to do, but never give up. There is a solution to everything, and Ludka and Brendan have found they’ve become really good at researching and solving problems.

    Projects don’t go the way you want them to, and you have to continuously pick yourself up from failure, but somehow it all makes sense in the end. Creating an OPD has brought a sense of integrity to Ludka and Brendan’s life, as well as a sense of community from within the One Planet movement itself.

    Find out more

    Huff and Puff Construction

    Hawkland Construction

    EcoCocon

    One Planet Developments

    One Planet Council

    Transcript

    Download a transcript of the interview with Brendan and Ludka Powell

    Get more in The Hub. Juraj Mikurcik explains how you build with the EcoCocon straw panel system

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  • HPH265 : Preserving the beauty of a building while renovating to EnerPHit standard – with Jonathan Kearns

    HPH265 : Preserving the beauty of a building while renovating to EnerPHit standard – with Jonathan Kearns

    Jonathan Kearns of Kearns Mancini Architects, describes how he tackled a high performance retrofit of a century-old building.

    Interview with Jonathan Kearns

    Originally from Dublin and a keen environmentalist, Jonathan emigrated to Toronto in 1975. He became an architect and by 2008 was looking to incorporate his interest in sustainability into his designs. This led him to take the Passivhaus training, with his first project using this methodology being the Reach Guesthouse renovation.

    Reach Guesthouse
    Reach Guesthouse before renovation

    Reach Guesthouse was an experimental exercise

    Located two hours east of Toronto in Prince Edward County, Jonathan took on a late 1800s post and beam farmhouse. At around 1700 square feet it had a ground floor with smaller upper floor.

    “And so, that project became my learning tool and sort of an experimental exercise in how to renovate an older building and draw all the best qualities out of it while at the same time enabling it to be superbly energy efficient.”

    Renovations tend to be more tricky than new builds

    Jonathan explains that the Passivhaus training that was developed for new buildings hadn’t entirely prepared him for the task. It took a period of stripping away and demolishing the worst parts of the house to establish whether it would even be worth renovating, but the more raw structure that they uncovered, the more they realised that they could end up with something very interesting and unique.

    A friend of Jonathan’s was an artist who in his free periods would also do some construction work. He moved to the site to carry out the selective demolition, using his artistic eye and considered approach to decide what would be worth keeping. This approach did mean the time schedule became stretched, but Jonathan considers it to have been time well spent.

    The house was enveloped in Structurally Insulated Panel cladding

    Jonathan worked with a local contractor specialising in Passivhaus home projects, who built modular pre-fabricated components in his shop in the local town.

    Using 12 inches of SIPs cladding as an insulated jacket to the building, they were able to create a house form very similar to the original. Jonathan describes it as being somewhat surreal to cross from the entirely white exterior through to the contrasting original woodwork inside.

    Later additions to the original farmhouse had been poorly built, so they chose to demolish them but use the same foundation to construct a kitchen / dining space on the back of the house.

    “So, again, even within the house, you have a very nice contrast of the intimate, richly wooded finishes of the original house, and then you go through into the kitchen dining room and it’s a one-and-a-half storey high open cathedral ceilinged space that is painted white on the inside and is white on the outside and has larger windows that overlook the garden.”

    Excluding the basement from the Passivhaus envelope was a painstaking process

    With the basement being shallow and built of local stone, Jonathan says there wasn’t much opportunity to incorporate it into the house, so lots of insulation had to be added to the underside of the floor to achieve an air seal.

    As they wanted to keep the beautiful, original wooden floorboards, they lifted each one from the ground floor, recorded where they had come from, and preserved and set them aside until later. A layer of Oriented Strand Board (OSB) was laid, taped and sealed, with all the edges being sealed to the outside of the exterior cladding of the original house, so that when the house was wrapped with an air vapour barrier it could be taped to the edge of the floor. The original floorboards were then re-laid.

    A particular challenge was the four posts of the house. To complete the air barrier they had to tape three or four inches vertically up each post and down to the floor membrane.

    The next project will be a Passivhaus new build

    “It makes me want to do new build more than renovation because with renovation, it’s a journey and you don’t know the route. You know what your objective is but you’re starting with something where you can’t see all of the challenges. So, it’s not until you get in and you strip away and you discover all the nuances, that only then can you really make the right decision, make the right design choice.

    So, the renovation project really needs you as the architect and designer to be very hands-on and very engaged in the process all the way through. Whereas with a new build, you can really design, think out, calculate and detail every aspect of your new build before you start construction.”

    Following Jonathan’s renovation experience, he is now constructing a new Passivhaus guesthouse, called Endymion Guesthouse, which is also in Prince Edward County. Being a completely new build he has been able to site it facing south the way he wanted, and has chosen an ICF construction which could be built by a builder without much Passivhaus experience.

    His approach to sustainability has changed

    Jonathan says he has always liked the landscape and ecological approach to architecture. He went through periods of being very immersed in looking at photovoltaic panels, wind turbines and the use of geothermal for heating and cooling, but when he studied the Passivhaus methodology he realised they were all secondary to building the primary architectural enclosure to an extremely high performance level.

    At the Reach Guesthouse, they have very low energy consumption in summer and winter months for heating and cooling, and the shoulder seasons quite often rely only on keeping the energy inside the building that has been generated by people and appliances.

    Something Jonathan enjoys about Passivhaus is he feels it allows him the freedom to work with any material that is appropriate to the design, programme, location and landscape, whilst applying the science as stringently as possible.

    Find out more

    Visit the website of Kearns Mancini Architects

    Follow Kearns Mancini Architects on Twitter

    Read Lloyd Alter’s Treehugger article about the Reach Guesthouse

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    Download a transcript of the interview with Jonathan Kearns

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  • HPH237 : A SIPs Passivhaus build on a tight budget – with Richard Dudzicki from RDA Architects

    HPH237 : A SIPs Passivhaus build on a tight budget – with Richard Dudzicki from RDA Architects

    Architect Richard Dudzicki explains the tricks and challenges of designing a £500,000 house on a £250,000 budget.

    Interview with Richard Dudzicki

    Richard’s practice concentrates on residential architecture, initially with ecological buildings but now with a focus on Passivhaus. He likes the physics that tells you how the house will perform, and the results that it achieves.

    It is not uncommon for Richard to have taken on multiple projects in the same street, based on recommendations, with the Passivhaus Mews II development being one of those.

    A difficult to access site in a conservation area

    The site is off a Georgian street in an historic part of London, around the back of Camberwell Grove. The buildings on the main road are Grade II listed, and the Mews where they have built the Passivhaus falls within the conservation area.

    The ground conditions in the area can be challenging, as they are London clay, and with the numerous mature trees there can be problems with subsidence.

    The brief had to develop to include a newly purchased swimming pool

    The client was a lady in her seventies, at the time living in one of the Georgian houses but finding it too large for her needs. She wanted to take a section of the garden and build a modern, 120 square metre, three bedroom home with a courtyard and off-street parking, for £250,000.

    In order to keep down costs their first application was for a rendered exterior, but this fell foul of the planners, conservation department and Camberwell Society, who didn’t want a mock pastiche of a Georgian building, but instead wanted something of the time.

    During the development of the plans, Richard had been able to persuade his initially reluctant client to build to the Passivhaus standard. It was at this time that she also announced she would need garden space for the pre-fab training pool that she had just put a deposit down on!

    One of the biggest challenges was fulfilling the need for off-street parking, and designing it for a large, electric car that would likely be more commonplace in the future. The building envelope, being a rectangular box shape, had to have an area taken out of it on the ground floor for the parking space. With the house not being wide enough to have a garage and door, they used it as an internal courtyard outside of the thermal envelope. That meant they had a larger surface area exposed to the cold which in turn added around £7,000 to the cost for additional insulation required.

    SIPs panels were ideal for the limited access at the site

    One of the logistical elements of designing the building package was how they were going to get everything on to the site, and that’s where the SIPs panels came in. They designed it in such a way that they would be able to do it in three lifts, for a total price of £47,000 including all of the structural elements and insulation, from Kingspan SIPs Panels.

    The speed and necessary logistics for accessing the space meant SIPs were an ideal construction method, and they were able to have the whole building erected in under three weeks. The panels they used were lightweight and thin, which was necessary for the limited site space they had.

    Consider condensation if insulating on the inside of SIPs panels

    Richard gives a word of caution about insulating on the inside of SIPs panels, as you can have interstitial condensation. It’s therefore important to have a condensation risk analysis done. Putting the insulation on the outside makes it easier to adhere to and easier to deal with airtightness.

    Airtightness was tested at different stages

    Built into the contract was that there needed to be three air tests carried out. The first one was as soon as the building was erected, without the windows. Instead they taped up the windows and doors with a damp-proof membrane and tested the frame, making adjustments to improve the airtightness where necessary.

    The second test took place once the windows had been installed. The result of this test proved that the manufacturers didn’t know how to correctly install Passivhaus windows, so they had to come back and do them again.

    “Specify with whatever contract you’re using – whether it’s the window manufacturers who are doing it or whether it’s your main contractors installing the windows – that you’re clear cut and you’ve got a piece of paperwork before you’re paying for it, that these will be installed to whatever airtightness you want them to. And then have an air test afterwards and then you can cross check it. Because without that, once the windows are in and you’ve started putting the plasterboard on, you’re screwed. ”

    The contract protected the client from financial loss

    On this job they used two RIBA domestic contracts: one to cover the main building and one for the foundations. This provided protection for the client when the main contractor went bankrupt half way through the project. The client didn’t lose money from it, but they did lose around 4 months of time while the contracts were sorted.

    A £500,000 house for a £250,000 budget

    The client wanted a very palatial feel for the interior, so a lot of time was spent looking at what she wanted and then working out how to substitute materials to bring it within budget. One way of saving money was to build the staircase out of MDF and paint it white, to give the effect she was looking for. 

    The kitchen was imported from Italy, and even with the 2000 Euros delivery fee, worked out to be a good deal. 

    Richard advises against buying individual pieces on eBay, because unless you have a very cheap facility in which to store them, storage is going to be a problem. 

    A chunk of the budget did have to be spent on a few bespoke items, like the front garage doors that roll back, and the garden deck that slides back to reveal the swimming pool. 

    One of the other complex issues on this building was making the rooflight work without spending silly money. They achieved it by developing a system of sitting the rooflight in a foam glass sandwich. It also wasn’t helped by the original builder having installed double glazed units instead of the triple glazed that had been specified. They got round this by putting in a further double glazed unit to create a quadruple glazed rooflight. 

    “The other thing that’s important with anything where there’s a tricky situation like Passivhaus, for instance, or anything with complexity – Passivhaus isn’t complex. It’s more a question of keeping an eye on the builder. What I mean by this is be careful when you go to site and make sure that you’ve got someone who’s got experience, who’s cross checking what the builder is doing. Because if you move past the stage where it’s too late to fix it, that’s where it can get really expensive.” 

    Be strong and stick to your ideals

    There was many a time that the client had doubts about Passivhaus and wanted to leave it, but Richard stuck to his principles. Thankfully the client now loves it and proudly shows off her house at Passivhaus open days. 

    In terms of what Richard has learnt from this job, “I suppose for me as a practice, don’t listen to clients when they come up with builders ideas if you’re not very sure that the builder is any good.”

    As a practice Richard thinks they probably made a loss on this job as all the R&D on the project probably amounted to three-times the number of hours that they actually charged for. Richard however considers it a research project from which there was a huge amount of valuable information they were able to benefit by. 

    Richard explains that the physics of Passivhaus is about 10% of the challenge, but making the house work for the client makes up the rest. There are many questions that he says a client needs to work through, rather than just thinking ‘I want to design myself a Passivhaus’. These would include how many children will live there, how long you plan to live there, whether it’s going to be left to your children, the longevity of the house, whether it needs a ten year warranty, etc.

    “And one of the things I have learnt from this… is Passivhaus is a fantastic system but don’t let you be swayed by just Passivhaus rules, regulations and what you can and can’t do. Basically, you can do anything as long as you’ve got an architect who understands what Passivhaus is about. You can design pretty much any sort of building you want to and apply the principles to it. And I think that’s really important.”

    Find out more

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    Download a transcript of the interview with Richard Dudzicki.

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  • HPH233 : How to choose a construction system for a house build – with Mike Hardwick

    HPH233 : How to choose a construction system for a house build – with Mike Hardwick

    Self build consultant, Mike Hardwick, explains the pros and cons of different construction systems.

    Interview with Mike Hardwick

    Mike hasn’t followed a typical path into the industry. He actually worked in the RAF for 26 years, and with all the different postings came many different house moves for him and his family. Deciding to settle in one place they selected a location (based in the middle of where possible future postings could potentially be), bought a plot of land and built their own home.

    Mike often found himself propping up the bar in the Officers’ Mess answering questions about how to build your own home. When he came out of the Services in 2005, he realised that what he would really like to do was get more people interested in building their own homes, and at that point decided to make a business from it.

    The first series of Grand Designs – copyright Channel 4

    Mike’s house build coincided with the first series of Grand Designs

    They bought the land for their self build in 1999, got planning permission in 2000 and in 2002 were able to move in. Doing the build in parallel with the first episodes of Grand Designs often left them able to empathise with the self-builders, pick up a few tips or wonder why they were doing things a certain way.

    Mike credits Grand Designs for redefining the scope of self build, making people realise that it doesn’t have to just be for the very wealthy. Although he does concede that the TV programme “Sensible Couple with Reasonable Budget Build Modest House On-time and On-budget with a Competent Builder” is never going to get commissioned!

    A build system is the structural element of the house

    That is, what it is built from and held up by. “And the confusing bit with a build system is that just because what’s on the outside of a house looks like maybe a brick, it doesn’t necessarily mean that it’s a house made out of bricks structurally.” Most, but not all, houses in the UK are built with a twin-leaf construction, where the inner leaf does the supporting work and the outer leaf makes it look pretty, with timber, brick, tiles etc.

    As well as holding up the structure of the house and being the main material used in the construction, it is what the services run through and are bolted to.

    As such, getting the right system for you is going to be an important decision to make, and generally it’s entirely your choice. Because the building system you use doesn’t usually dictate the external appearance, the planners aren’t interested. So as long as Building Control are happy that it will comply with regulations then you are free to choose.

    Price comparisons aren’t straight forward

    Mike explains that people will always ask him which system is the most cost effective, but drawing a price comparison is actually quite difficult. He does say that there is a fairly narrow band of cost when it comes to the different build systems, and what influences the price most is actually the detailing and the finishes that go on inside.

    What really hikes the price is when you trade in the materials for speed of construction, such as with houses that are pre-fabricated and then erected on site in a matter of days.

    Masonry construction

    Mortgage companies for example will typically ask whether the house you’re buying is of masonry construction with a tiled roof. They like it because it has substance to it, it’s a safe thing to invest against, and will be appealing to potential future purchasers.

    “It’s the way that we’ve trained our builders, it’s the way we’ve been conditioned to think about how houses work, and it’s what we fall back to. So, they’re easier to insure, they’re easier to mortgage against and they’re easier to sell. Which is why people still do it.”

    If you’re working to a modest budget, then using brick and block is generally at the lower end of the cost spectrum, so is likely to be a baseline for constructing your own home. They are quick and easy to build, relatively cheap to buy, and are easy to handle and cut up. They tick the boxes for mortgage companies, insurers and builders.

    Other positives are the strength they provide, that you can put beam and block floors in. The thermal mass provides a stable temperature throughout the house, and the masonry affords you flexibility of design. You can build just about anything you want in masonry, and combined with steels can give you large, open spans.

    Traditional breeze blocks were made out of cement covered cinder. Modern blocks are lightweight and made from pulverised fuel ash, so the detritus from a coal-fired power station mixed with resin and turned into a block. The aerated middle traps air and provides insulation, and also makes them lighter.  In the UK there is currently a shortage as there aren’t many coal-fired power stations remaining, so the raw materials have to be imported.

    Timber frame

    Timber frame basically replaces that breeze block element with a structural framework of timber. It is associated with being environmentally friendly, high quality, accurate off-site manufacture. It is efficient, effective and with the speed of construction it makes for an attractive proposition.

    Whereas masonry has high embodied carbon in the manufacture, timber frame is carbon neutral in that you plant a tree, chop it down and plant another tree. Timber is also a flexible material in that you can build the walls, ceilings, floors, windows, doors, stairs etc from it.

    Mike is keen to point out to people who worry that building a timber frame system might suffer from problems such as termites or rot, that probably around 65% of what we would call a masonry house is actually made from timber anyway, being the roof trusses, stairs, skirtings and so on.

    Mike concedes that, if pressed, he would say timber frame is probably the cheapest way of building the structure of the house. But that would only be if you were doing the most economical and basic timber frame with no frills, and without doing anything to attenuate the acoustics. Most self-builders would want to go above and beyond building regulations and put in good sound-deadening insulation to minimise noise transmitting through the house. When taking into account the extra money on the sound-proofing, you are probably then looking at a more expensive path than masonry.

    “Now, if you want the environmental stuff but you don’t want a lot of noise transmission, timber frame with noise attenuation is a good thing but it’s going to cost you more than it will for a masonry house straight out of the box. This is where you need to start doing your homework and making your calculations about what you actually want, how you’re going to live your life, and what you’re trying to get from the home that you’re building.”

    The thing to remember with timber frame is that it will last well as long as the moisture content in the structure is kept to a minimum, and allowed to escape so that it doesn’t build up. On the inside of the house behind the plasterboard there will be a non-breathable, vapour control layer. This stops any moisture occurring inside the property from getting into the structure. On the external wall, underneath the render or brickwork, is a breathable membrane, allowing any moisture that does get inside to find a way out.

    Insulated Concrete Formwork (ICF)

    These are a type of fire retardant polystyrene foam block. They fit together to create a solid outer wall and a solid inner wall, with the gap in the middle being filled with poured concrete. When the concrete sets and cures, you end up with a waterproof, insulated, monolithic wall which is highly insulated, highly airtight and with the strength and density of a masonry wall. This makes it popular for people building to the Passivhaus standard.

    It also benefits from being very quick to construct, you don’t need to be too skilled to put it together, and being waterproof is a good choice for flood-prone areas.

    Some people aren’t keen on this method because of the perceived embodied carbon being quite high. In reality, Mike says, they are mostly made of air with very little actual structure to them. There are other alternatives, such as Durisol blocks which are much the same in principle but use chopped up timber instead of the polystyrene foam as the insulant.

    Although there is a lot of concrete used, Mike suggests thinking about the amount of energy that the structure saves straight away with its high levels of airtightness and thermal performance.

    It is worth thinking about future use, as putting in more doors or windows for example at a later date is going to be very difficult. Also perhaps a marine ply or a Thermacell type board is advisable for indoors when there might be considerable weight such as cupboards or TVs to be hung from them.

    Structurally Insulated Panels (SIPs)

    These are manufactured off-site and built of two oriented strand board (OSB) sheets that are filled with expanded urethane insulation foam. The panels can be cut, shaped and fixed to other panels to make a complete housing structure. They tend to be accurate, airtight, watertight and put up on site very quickly.

    If you were thinking of using this building method, you would take your designs to a SIPs company whose CAD systems would create the plans to feed into the machines that produce the panels to millimetre perfection. These panels work with the other panels around them, and can even have steelwork in there for covering large spans, to give the structural integrity to the house.

    Mike explains how the success of a masonry constructed home is very dependent on the quality and skill of the bricklayer. With ICF it’s harder to go wrong, as the panels are designed to fit together at 90 degrees, meaning the walls are going to be straight and it will be easier for fitting out afterwards.

    One drawback is that you can’t later decide to move things about or add doors or windows because the structural integrity will be compromised.

    “The advice I would give to anyone contemplating building in SIPs is to spend a really long time thinking about what you want and what’s going to go into your house, and the design of your house, and then say, ‘that’s it, no more changes. We’re happy with this. Go and provide this house.’ Because once it goes into the computer and they pull the handle, then that’s what you’re going to get. If you suddenly say, ‘about that wall there, can we have another one here or another window here? Can we have that door moved to the left?’ that’s going to be expensive, it’s time consuming, you’ve got to start again and recalculate the whole thing in the worst cases.”

    In terms of cost, Mike says ICF and SIPs used to have roughly a 10% premium on them because there were new factories to be paid for, but as they are becoming more common-place the prices are more competitive. Some manufacturers are even assuring that they can produce a house for about the same cost as brick and block.

    Straw bale

    Previously seen as something you wouldn’t consider for mainstream building, nowadays the increased focus on energy efficiency, natural materials and environmentally conscious building has given straw a greater appeal. Mike explains that structural straw bales, as opposed to ones you would buy direct from a farmer, are processed and compacted to form dense blocks.

    “When you encapsulate this within a lime water and plaster that you would normally be using with this build, you’ve got something which has got no oxygen. So, it doesn’t catch fire. It doesn’t. It’s just a really good carbon neutral method, environmentally friendly way of getting all that insulated wall which looks really good as well.”

    Straw bales do mean that you end up with thick walls, but for some people that is a positive feature. The deep window and door reveals combined with the lime plaster make it look and feel like a solid house with a natural, rustic feel.

    Mike concedes that some mainstream lenders and insurance companies might not be keen to deal with these, but others like the Ecology Building Society see the benefits and will lend against them.

    Prefabricated system builds

    Most of these factories tend to be in continental Europe where the prefabricated kit is made and then brought to your plot to be assembled. This method probably won’t suit those on a smaller budget but for projects on a grander scale, or at least a grander budget, they will be rewarded with superb, quality finishes.

    “And for those people who want to be hands-off with the self-build rather than actually getting involved and really worrying about how the bricks go and how the timber frame is constructed, they can sit back and basically say, ‘here’s the house I want. Build me one of those. Here’s where I want it.’ And somebody else goes and does it for you. You pay for the privilege of doing that, but the stress levels are going to be a lot lower than somebody who’s actually project managing their own build all the way through.”

    Again, this is a system where decisions need to be made up front as any changes later are going to be extremely costly.

    Steel frame

    A steel frame self build house wouldn’t be commonplace in the UK. They tend to be more popular in warmer climates. If you have a steel structured house and are trying to stop cold-bridging then you’re starting from a losing position.

    However, recent changes in planning regulations, where permitted development allows people to take farm buildings and convert them into residential dwellings with less of the hassle, has made extensions and renovations of steel-framed farm buildings more common.

    Thin joint

    The masonry industry has recognised some of the problems of building with blocks (weather dependent, speed of construction, reliant on quality of the builder) and come up with a variation on the masonry theme called Thin Join. They use over-size versions of the cinder blocks and instead of using a 10mm sand and cement mortar base, they are held together with a type of glue adhesive.

    “But by taking out things like the mortar bed, you’re taking out two things. One is a passage for air to get through, and when air can get through, noise can get through. So, by taking that mortar bed out, you’re putting better airtightness into it, putting more insulation into the wall and you’re taking away some of the need for skilled construction to put it together”.

    It’s also a cleaner system, using a bucket of adhesive instead of having piles of sand and cement spreading around the site.

    Which system to use depends on what is right for your circumstances

    “So, if low cost is your priority then you need to be looking at the traditional masonry or the timber frame setup. If you’ve got family and you want a bit of peace and quiet, you want some separation of noise, acoustic attenuation, then the masonry end is probably the way you want to be looking at.

    If you want energy efficient, you’re environmentally aware, then you want high efficiency and low running costs. Then timber frame is probably where I’d be looking at. That’s at the lower end of the spectrum on there.

    And as you go up the performance scale, that’s when I’d start looking at the ICFs and the SIPs panels. They might cost you a little bit more to build but again, there’s a trade-off there against the cost of the materials and you need less labour to put it all together.

    At the very top end, if you really are a hands-off builder and you want the sort of quality which just comes with that continental standard, then these system builds that we spoke about, hand over the money and let these guys come and build it. You’ll have a house which will be good enough to feature in the magazines. But you will pay for that privilege.”

    Additional resources

    Build It Magazine

    NaCSBA

    National Self Build & Renovation Centre

    Transcript

    Download a transcript of the interview with Mike Hardwick.

    Please connect with me

  • HPH227 : What’s the best way to build an airtight structure? – with Paul Jennings

    HPH227 : What’s the best way to build an airtight structure? – with Paul Jennings

    Air leakage expert Paul Jennings looks at how best to achieve that all important airtightness when using particular construction methods.

    Interview with Paul Jennings

    Paul Jennings is an air leakage expert with over 25 years experience. In our previous interview with him he explained how to achieve airtightness in low energy buildings. He also appeared in our documentary “The Future of Housing – and How Airtightness Can Help”, taking a look at housing construction quality and building performance to see how they could be improved.

    For this podcast, he looks at some of the issues with achieving airtightness in different construction types.

     

    Cross Laminated Timber (CLT)

    Paul recently tested a bungalow that was built using Cross Laminated Timber. The airtightness is essentially in the timber, and in this bungalow there were up to 8 laminations in each of the panels. The roof was a sandwich panel with layers of lamination, insulation, and more laminations on top. With the panels being larger than standard OSB boards, there is less taping involved. Each panel is also very strong, and strengthened further when screwed together. The taping goes where the panels butt up to each other, around windows, ventilation ducts, sun pipes etc. Once you have taped to the timber you have airtightness.

    Paul is starting to think that there is no need for a membrane on the outside. The CLT doesn’t meet insulation values but he thinks it’s perhaps easiest to insulate it externally and make it airtight on the inside.

     

    Structural Insulated Panel Systems (SIPS)

    Paul has experienced very good results with SIPS panels, which he feels have the potential to be very airtight. So far he hasn’t seen anyone using the airtight OSB as one of the faces of a SIPS panel system, which he thinks could improve it further.

    He explains there is a difference in results depending on whether foam is injected into the pre-made box, or whether a piece of foam is cut and put into a section of wood which then has sides added. The latter won’t be as airtight.

    SIPS panels can be a problem on site if they get saturated with water as they take such a long time to dry out, and the airtightness tapes do not adhere properly.

     

    Masonry Construction

    Masonry construction ticks the box of being a system that normal builders are used to building, where most materials can be sourced from a standard builders’ merchant. Paul offers Denby Dale Passivhaus as a great example of this.

    Paul explains that any construction with a cavity in, is a weakness for airtightness. If air can move laterally it can get around things and leak where you wouldn’t expect it to. He prefers a masonry build that has a masonry wall which is ideally wet plastered for airtightness on the inside, with insulation and render on the outside.

    “Because at that point, you have to have a continuous hole from the inside to the outside. You can’t have a hole through the inner leaf, then air moving in which way it likes in a cavity and then coming out somewhere else. It’s more robust for airtightness.”

    Paul points out that almost every masonry build has a timber frame roof, so as soon as you’ve opted for masonry construction you’ve doubled the number the number of build forms in your house anyway.

    Paul emphasises how the more complicated a build is, the harder it will be to achieve the airtightness. There is greater scope for people on site getting confused, doing the wrong thing or not checking details properly.

     

    Modular construction

    This isn’t a widely used construction method in the UK but there are increasing numbers of companies trying to develop it. The benefits of this method are that production has less of an issue with weather, shortage of trades people etc, than for on-site construction. The ones Paul has seen have been generally at a prototype stage with initial positive signs and great potential. He believes they will have to be built to be incredibly robust, as otherwise they wouldn’t survive being craned on to a lorry, driven to the site and craned off again.

    One of the big advantages of modular construction is there is less time spent on site, which means less financial impact from weather delays, and less overheads on things like site supervision, site cabins and toilets.

     

    Airtight OSB is gaining in popularity

    The trend that Paul is seeing at the moment is that membranes are losing out to the airtight Oriented Strand Board (OSB) and, for refurbishment particularly, to blowerproof paint. The most popular he currently sees in the market, and which he thinks are proving to be very successful, are the Durelis and the Propassiv.

    “At the same time, the refurbishment market is a bigger market than the new build market. We need to tackle refurbishment and we need to tackle it better. And we’re not. We’re learning lessons but really we’re taking our time over getting it and I don’t think we can afford that time.”

     

    Choose the right tape for the job

    Choose the right manufacturer, and the right tape. For example, don’t try and use 50mm tape to cover a gap of 60mm. Choose one that is wide enough for the gap.

    Paul believes the two best products for airtightness are produced by SIGA and Pro Clima. But no matter how good the tapes, most important of all is how well they’re applied.

     

    Plan early and get advice from the experts

    “You really want to get your designing done early, get your planning done early and then don’t mess with it. Because every time you change it, there will be unforeseen consequences. Usually those will be things that make your airtightness worse or harder at least.”

    Paul encourages self builders to take advantage of the Passivhaus Open Days and talking to the people who have built them. There are also the AECB and UK Passivhaus conferences that people can attend and find out more about the network of experts.

    “There are networks of people and a lot of them are very committed people. They give their time, they give their energy and they often don’t charge as much as they should for it, because they believe in it.”

     

    Find out more

    Visit the website of Design Buro

     

    Transcript

    Download the transcript of the interview with Paul Jennings.

     

    Please connect with me

  • HPH168 : An example of how much it costs to hire an architect – with Allan Corfield

    HPH168 : An example of how much it costs to hire an architect – with Allan Corfield

    Allan Corfield from Allan Corfield Architects (ACA) explains how his approach to services and fees differs from traditional architecture practices in the UK. He describes the staged services his practice offers, giving indicative costs.

    Interview with Allan Corfield

    Allan Corfield is an architect who aims to educate and help homeowners deliver their one-off dream home. He’s spent the last eight years building his practice based in Scotland focusing on self-builds. Their location isn’t an obstacle to working further afield as Allan factors into each fee proposal two or three face-to-face visits during each stage. Currently working on their 250th project, they now operate across the UK and are involved in projects with construction costs ranging from £70,000 to £2 million.

    Percentage-based fees will increase if construction costs go up

    Allan’s approach is different to the majority of traditional architecture practices in the UK who work on a percentage basis, charging 7-10% of the construction cost for their services. Allan prefers his approach because self-builds have a set budget and if you don’t know what your architect’s fee is going to be, you can’t plan ahead. He also argues there’s no incentive for an architect to save you money if their fee will drop in line with reduced construction costs.

    As can be seen on the ACA website, Allan’s practice splits the build process into different stages which are priced separately as fixed costs. This allows self-builders to budget for architectural fees knowing they won’t change as the project goes on. At the end of each stage, ACA asks if clients are happy to go ahead with the next one. Allan recognises that a self-builder may run out of money or there may be a change in family circumstances meaning they can’t commit and finish their project. So his approach offers flexibility and the ability to stop if necessary.

    An example of ACA’s fees based on an estimated construction cost of £250,000:

    StageFixed Cost (excl. VAT)% of Total Fee
    Initial Design Development£5,00025%
    Planning Submission£4,00020%
    Detailed Design Development£6,00030%
    Production Information£4,00020%
    On-site Supervision£250 per visit (optional)5%

    A detailed project brief is essential for the design stage

    Allan explains, “You want to get a design that you love, so that’s our initial design stage”. The most important thing for a client to get right is the project brief. ACA encourage clients to think about how they’ll use their buildings, e.g. an outdoors family may benefit from a wet room attached to their garage. Clients considering details like these help the architect design a home, not a house. ACA ask clients to create lots of different Pinterest boards, including a dislike board, as this helps them gauge what clients like aesthetically.

    ACA use the client’s project brief to propose a couple of initial design options, usually two variations on a theme. Often a third option evolves by combining preferred elements from the first two, which is then typically revised a couple of times until the client’s happy. Their design service ranges from 2-D drawings for lower budget projects to full 3-D modelling where clients can ‘walk around’ their house.

    The first stage also includes a cost check to ensure the design is affordable and self-build elements are achievable. And if there are any contentious elements that could affect planning permission, for example rural location, they make a pre-application enquiry or get a planning consultant in during the design stage.

    Make neighbours and planners feel they’re part of the process

    The cost of the planning stage may seem high but a lot of work goes into getting a planning application approved. Allan explains their high success rate is due to the amount of supporting information they provide, saying, “We’re very good I think at getting a lot more of our clients’ desires through the planning process than other practices because we give really good rendered images.” The thinking behind their design is explained in detail using a Design & Access Statement accompanying the application.

    ACA always ensure they know the local planning policy. Allan comments, “Actually it doesn’t matter where we are or where we come from. If you know the regulations and why you’re going to get something through planning, you shouldn’t have an issue.”

    Before submitting an application, Allan recommends clients discuss their drawings with neighbours so they feel they’re part of the process. While some may have objections, you can also benefit from letters of support.

    It’s advisable to get certification before starting to build

    The third stage is detailed design development. The architect and engineer will spend time researching and inputting information like SAP / PHPP calculations, but many things need to be confirmed by the client such as construction methods, materials, finishes, heating strategy and the level of energy performance.

    Within England’s building regulations system there’s an option to give notice to start work followed by a drip feed of information as the build goes on. Allan realises this can seem attractive to self-builders who may have experienced delays and be eager to get started. However, he prefers to put together a well thought out and detailed package for review and approval before construction starts (as is mandatory in Scotland), cautioning, “If you do rush ahead it will always cost you more in the long run.”

    Construction drawings show how the design should be built

    Stage 4 is called Production Information. The level of detail required in the previous stage demonstrates compliance with building regulations but doesn’t show precisely how the design will be built. Construction drawings are particularly important for self-builders, to ensure contractors use the methods agreed between client and architect.

    With low energy buildings or fabric first approach, you’ll need to have all the details worked out because there may be methods and products that are new to the builder. And with off-site construction methods, it’s down to the client to review and sign for a set of drawings and make sure they’re in line with the window and door schedule (e.g. ensuring the window openings match the kit size), so the cost of retaining your architect to help make sense of the complicated documentation is money well spent.

    You may not need as much on-site supervision as you might think

    The final stage is on-site supervision. In England, building control inspectors visit the site to assess work and provide assistance, but limited funding in Scotland means they don’t have time to come out, so you don’t have that safety net.

    Traditional architects often ask for a monthly retainer for site visits, but Allan feels this shouldn’t be necessary if the architect has provided all the required information and you’ve hired competent contractors. So ACA usually provide an adhoc service for this stage, charging a fixed price per visit if the client requests one. The exception to this is when ACA provides mortgage certificates, where they have to certify a phase of work (e.g. groundworks) has been completed before the lender will release the next chunk of money.

    Architects should be able to justify their fees

    When a project ends, ACA compare the time spent on that project versus fees charged. Quarterly reviews also help to ensure their fees are set appropriately, which will vary according to a client’s budget and requirements.

    Allan comments that building your own home is a very personal thing, and the deciding factor when choosing an architect shouldn’t be solely cost. He acknowledges his practice is slightly more expensive than some of their competitors (but a lot more cost effective than a comparative practice down south, even accounting for travel costs) and justifies their fees, saying, “We’ve got a better team, so we can charge the fee that we do because we actually deliver on what we need to.” He adds the majority of their clients take the full service through stages 1-5 and nobody has come back and quibbled over the fee.

     

    Find out more

    Visit the website of ACA

    Follow AC Architects on Twitter

    A big thank you

    Ben would like to thank Chris Marr from the Content Marketing Academy for connecting us to Allan and for facilitating the interview.

    If you’re a business owner, looking to serve your customers better in our digital world, it’s definitely worth learning more about what Chris does.

     

    Transcript

    Download a transcript of the interview with Allan Corfield

    Please connect with me

  • HPH124 : A contemporary Passivhaus home, built with SIPs – with Paul Newman from Potton

    HPH124 : A contemporary Passivhaus home, built with SIPs – with Paul Newman from Potton

    Paul Newman from Potton talks through the construction of the UK’s first Passivhaus show home.

     

    Interview with Paul Newman

    Paul Newman is the Self Build Director at Potton. Potton, which recently celebrated their 50th anniversary, have helped design and build over 6000 homes and have a portfolio of over 12,000 different designs. The Potton approach to custom build is to work with landowners to secure outline planning permission on their sites, with design left as a reserved matter. They find customers for those sites who then buy the land from the individual landowners. Potton then work with the customers to provide their normal self build package.

    At their site in St Neots they have a show centre of completed houses, where they are currently adding a Passivhaus. They have been sharing progress of this build with video updates and have also allowed members of the public to experience it being built.

    Potton Passivhaus mock up

     

    Building a Passivhaus show home was an obvious step

    Potton have four complete show homes at their St Neots site and one at the National Self Build and Renovation Centre. Moving with the changing market and increased demand for low energy homes, their last show house was constructed to achieve level 4 of the Code for Sustainable Homes. Wanting to move their business on and offer customers something new, they decided to construct a further show house, with a Passivhaus being the obvious choice.

    Their experience over the last 8 years has been that they’re being asked more and more often about energy efficiency and low energy homes and hope that this Passivhaus and the lessons they have learnt from it will put them in good stead for the future.

     


     

    The design aimed to push the Passivhaus standard hard!

    In coming up with the design Potton were keen to challenge the reputation that Passivhaus buildings sometimes have of being simple, boxy designs. They expect to evolve different design forms based on this Passivhaus, while not necessarily directly repeating it.

    They worked with HTA Design, an external design consultancy, on the plans, and also had specialist help from Passivhaus experts WARM.

    The building form is quite complicated and has a valley roof, so from a thermal bridging perspective the junctions have been tricky to resolve. Paul also thinks their life would have been much easier if they’d taken 18 inches of height off the design!

    Potton Passivhaus cross section

    Something they found encouraging was the use of an innovative self adhesive breathable membrane which has contributed positively to the building’s airtightness. The first airtightness test had a figure of 0.68 but after some alterations they managed to get it down to 0.5.

     

    The SIPs system took a matter of days to install

    The house has been constructed with Kingspan Tek – a product which is certified by the Passivhaus Institute – and Potton have been using it for the last 10 years on both their self build and volume contracting business. It provides a thermally robust solution and can be erected on site very quickly. One consideration, however, is that once installed it is hard to make changes to room layouts, etc.

     


     

    Use PHPP modelling from day one to see how the building is performing

    Paul explains that early modelling in the Passivhaus Planning Package was an important lesson for them when designing the Passivhaus. By doing this, something that showed up early on was that the building had a tendency more than was desirable to overheat. They were able to experiment by changing the overhangs, reveal depths and specification of the performance of the glazed units within the windows to make a considerable difference.

     

    Engage with suppliers early in the process

    There are two main lessons that Paul feels they have learned from the Passivhaus self build process. The first is the need to engage early on with suppliers to make sure they understand what you’re trying to achieve, have the right products available and certifications in place where appropriate. While they did try and engage early with their supply chain, their lesson was that they actually should have engaged even earlier and placed some of their orders earlier too.

    Secondly, Potton worked with sub-contractors who they have used on hundreds of other Potton houses in the past. What they found was more attention to detail was required to achieve Passivhaus performance, and they needed to have their hands held tightly throughout. Paul thinks this is something that won’t be unique to their build, as there just aren’t enough experienced Passivhaus sub-contractors out there.

     

    Find out more

    Visit the Potton website

    Find out more about Potton’s Self Build Academy

    Find out more about Potton’s Self Build Live

    Follow Potton on Twitter

     

     

    Transcript

    Download a transcript of the interview with Paul Newman.

     

    The Hub update

    Our Getting Started module is for absolute beginners who want to know how to research a house build. We’ve laid out a logical route so you can get going.

    In the Long Barrow case study the latest video shows the steel frame going up, and explains the areas where they needed to be careful of thermal bridging as they wanted to attach a balcony and a brise soleil as well.

    Elements of The Hub are free to view, but for full access the price currently is just £45 for the year.

     

    Please connect with me

  • HPH120 : What is a self build mortgage? – with Thomas Honour of BuildStore

    HPH120 : What is a self build mortgage? – with Thomas Honour of BuildStore

    Thomas Honour, mortgage adviser at BuildStore, explains the self build mortgage process.

    Tom Honour (2)

     

    Interview with Thomas Honour

    In this interview we’ve returned to the National Self Build and Renovation Centre (NSBRC), this time to chat with Thomas Honour who works as an adviser with BuildStore mortgage services. BuildStore specialise in finance for projects, so self builds, custom builds, renovations etc. They have had a presence at the NSBRC since it opened, with a permanent base there for mortgage advisers who also contribute to the seminars on finance.

    IMG_4285

     

    Consult a mortgage adviser at an early stage

    This will help you to ascertain your borrowing capacity and determine whether your budget for the plot and build is is likely to be realistic.

    Salary is the single most important factor in determining available finance, but other considerations will include things like ongoing credit commitments, childcare costs and any other significant outgoings.

    Each lender is very different but typically they will apply an income multiplier of between 4 and 4.25 times the joint household income, with some treating bonus and overtime payments differently.

     

    There are two different types of self build mortgage product

    The main difference between a self build mortgage and a conventional mortgage is the way in which the funds are released. With a conventional mortgage you receive the funds in a lump sum, which together with your deposit, you use to purchase the property.

    With self build mortgages the money is released typically in four or five stages, over two phases. The first phase is releasing money to purchase the plot and the second phase releases money to finance the build.

    The traditional self build product provides money in arrears of the stage being completed. This works well for people that have larger deposits or who own the land, as they are putting in their own money upfront with the lender giving the money in arrears on completion.

    Construction types such as insulated concrete formwork (ICF), structurally insulated panels (SIPs) and timber frame however often require a much larger payment to the manufacturer early in the project. BuildStore have designed their “Accelerator” product to mitigate these cash flow difficulties by giving the money in advance of each stage.

     

    Your mortgage broker has a duty of care to ensure your mortgage is affordable to you

    The mortgage broker and lender will work together to ensure that your build costs are reasonable and that they’re going to be plausible for the type of project that you are doing. This aims to prevent the need for anyone to return mid-project requesting more funds, with no guarantee they will be provided, and will likely cause delays.

    On rare occasions people do return requesting additional funds. An additional loan known as a “further advance” or “additional advance” can be applied for to make sure that the build can be completed, subject to underwriting from the lender.

    It’s important that budgets are broken down in detail. Sometimes people may not have considered contingencies and additional expenses such as architect fees, stamp duty on land, site insurance and structural warranties. A mortgage broker would rather decline an application upfront than put them in a position where they have a project they can’t complete because they don’t have enough money.

    It is worth bearing in mind that most lenders will have some sort of caveat that the build must be completed within two years.

    Since the mortgage market review by the regulator a couple of years ago there is a greater burden on the lender to ensure they are lending responsibly. While Thomas believes that this is right and should be the case, some of their affordability criteria does limit the amount that people can borrow which means they may need to put more down as a deposit.

    Buildstore015

     

    There are costs to setting up a self build mortgage

    This will vary from lender to lender but as with standard mortgages there will be costs to get it set up. These may include:

    • An arrangement fee – most lenders will charge this as standard on any type of mortgage
    • Valuation fee – this will value the plot based on its value at the time and what you’re paying for it. They will also give an end value based on what you’re planning to build and what they think it will be worth when completed. There is also a reinstatement value for site insurance purposes.
    • Additional fees – some lenders may charge booking fees which are all quite similar but may be named differently.

    The job of your broker is to ensure you’re aware of all the fees upfront to know what they are, what they cover, what they’re costing you and when they’re due.

     

    A bridging facility may be suitable for people that have assets but a low income

    Thomas uses the example of someone with a house worth £500,000 but a pension income of £10,000, but wanting to borrow more than a typical mortgage would allow them on that income.

    Potentially there can be bridging finance secured against the existing home which would enable them to build their house. Money from the sale of their old home can then pay off the bridging facility.

     

    Not all lenders will lend on all construction types

    Non-standard constructions can be funded, however “non-standard” means different things to different lenders, so your mortgage broker will find a lender that is suitable for your project. Even timber frame, steel frame, SIPs and ICF constructions are considered non-standard by some lenders.

    The reason why some lenders won’t lend on less traditional buildings is largely down to re-saleability. The lender is always thinking about if they had to take possession of the property how easy it would be to sell. For properties that might be an acquired taste they will be worried they may not get their money back.

     

    The larger the deposit, the more favourable the interest rates

    Typically the minimum deposit required will be around 10% of the overall project costs. The project cost is the combined land and build costs.

    For someone that already owns the land outright, the value of the plot can be used as the deposit contribution, i.e. owning a plot with a value of £50,000 will provide £50,000 towards the deposit.

    A larger deposit will give more favourable interest rates and may make more lenders available to you.

    BuildStore

     

    Find out more

    Visit the BuildStore website

    Follow BuildStore on Twitter

     

    Transcript

    Download a transcript of the interview with Thomas Honour.

     

    The Hub update

    We’d like to tell you a little bit about The Hub – what it is and why we’re doing it.

    Support: A self build project can be a long journey so the community side of The Hub is a place to learn from others and be inspired by them.

    Information: We’re already providing lots of information with our podcasts and videos on YouTube, but this is going a step further by trying to refine and organise it, making a step by step and easy to understand guide of what’s involved in a self build.

    Videos: There’s huge potential for learning by video and here at Regen Media it’s what we specialise in.

    As content creators and communicators, we can do much more, not only in The Hub, but also by adding free content and perhaps help other people to achieve more and spread their messages further. If we can save you time and money by making The Hub work, then hopefully you’re paying for a resource that you’re happy with and which is giving us more funds that we can use to create in other areas.

     

    Please connect with me

  • HPH094 : 10 Insulation Types and When to Specify Them – with Brian Murphy from Green Building Encyclopaedia

    HPH094 : 10 Insulation Types and When to Specify Them – with Brian Murphy from Green Building Encyclopaedia

    Brian Murphy from Green Building Encyclopaedia runs through the most common types of insulation and explains why they each have strengths and weaknesses.

    BRMShoulders

    Interview with Brian Murphy

    Brian has spent 40 years in the industry, as an architect and as a specification writer. In that time he has specified over £2400 million worth of work, so knows a thing or two about insulation!

     

    Insulations Can Be Categorised Into One of Three Groups, According to How Heat is Transmitted

    These groups are conductivity insulation, convection insulation and radiation barriers. They each have different characteristics, and for this reason there might be a need to use more than one type for a situation.

     

    Brian talks us through the characteristics, and pros and cons of 10 of the most common types of insulation.

     

    1. Glass / Rock Mineral (Stone Wool) Insulation

    Usually the lowest priced, this tends to be the most widely used insulation. Its main use is for conductivity thermal insulation. It also rejects water and is fairly versatile in where it can be used, though it isn’t ideal for timber roofs or timber frame. Stone wool is often used when fire resistance is needed, and glass wool in an acoustic performance situation. Enormous amounts of energy are used to make the glass or stone wool products, for example to melt stone and then blast it with air to turn it into a fibre.

     

    Glass wool
    Glass wool

    Rock wool
    Stone wool

    2. Polystyrene and Other Plastics

    The plastics all have different characteristics, formats and some have different gases within them, and legislation over time has made those gases less harmful to the environment. The gases inside produce the bubbles, which is what makes the material insulating.

    They are versatile in that they can be blown in, sprayed on, expanding, applied as a solid material and cut to a concertina, etc. Some are water resistant and durable and can be used under floor slabs, in roofs and others used in Structural Insulated Panels (SIPs). The SIPs panels have very little of the radiant protection from solar gain but a lot of the required characteristics for conductivity thermal insulation, so heat that gets in is slowly let out and could risk overheating.

    Polystyrene foam
    Polystyrene foam

     

    3. Cellulose Fibre

    This is recycled paper or magazine waste which has been flaked and is blown into open or closed timber framed cassette cavities, either in a wet or dry method. It is blown in powerfully in order to reach every corner of the cavity. Blown in methods reduce the risk of heat loss or condensatioin the imperfection gaps created by cutting insulation boards and batts to fit frames.

    CelluloseFibre

     

    4. Sheep’s Wool

    As well as being hygroscopic and effective in terms of moisture buffering, Brian says that some research has found sheep’s wool strangely warms up when wet and cools down when dry.

    It’s eco credentials are challenged however by some quarters focusing on the high methane levels from the sheep! Historically, also, UK sheep have been dipped, leaving chemicals in the wool which have needed to be processed out. Modern farming practices have moved on.

    Brian explains that another issue is that sheep’s wool can be squashed whilst packed, though some products on the market have plastic fibre added in to bounce back to full thickness. Sheep’s wool is used in timber framed construction and roofs.

    SheepsWool

     

    5. Cellular Glass

    Brian explains that this is versatile but can be more expensive than many other insulation materials. It is fire resistant, rot resistant, animal and rodent resistant. It has vapour resistance and is watertight but should always be encapsulated with water resistance to avoid frost damage. It has conductivity resistance, and has radiant heat barrier properties.

    It is ideal in roof, gutter, basement and foundation construction. Because of the cost, Brian recommends using it where you can afford to, with damp places being ideal.

    FoamGlass

     

    6. Dense Wood Fibre

    This is extremely versatile and comes as a rigid, soft or combination material. It has acoustic, conductivity and radiant barrier performance, and can be used in or on timber frame or roof and for external insulation with render or rainscreen weatherboarding.

    It is also ideal for retrofitting old properties with solid wall construction which need to be able to breathe inwards or outwards. Exceptionally one manufacturer has developed a version for partial ventilated cavity masonry walls; not normally recommended.

    Dense and soft wood fibre
    Dense and soft wood fibre

     

    7. Aerogel

    This is a silica based product that was invented by NASA. It can be very thin and exceptionally high conductivity performance and is popular when used with other materials for dry lining walls. Comparing it in price to some of these other materials it can be expensive and therefore Brian suggests again using it only in the places where it is needed; such as at thermal bridges that risk condensation and mould. Examples include: at door and window surrounds and where rainwater and soil pipes interrupt external wall insulation and below DPC; but they need specially developed weather and ground water protection to survive.

    Aerogel+Boards

     

    8. Calcium Silicate

    This is a very lightweight material that was designed for historic buildings. It is low impact, high performance with good moisture transport characteristics allow in solid walls to breathe.

    CalciumSilicate

     

    9. Vacuum Insulating Panels

    Air is sucked out of a silica ball filled, aluminium foil wrapped panel to create a vacuum. They’re ideal for a modular design where things don’t have to be cut to size. In a retrofit situation they would probably need to be combined with another material, such as aerogel or dense wood fibre; but bespoke sized panel services are also available.

    These panels would need to be used in areas where there would be no risk of someone accidentally nailing or drilling a hole into them!

    vacuum_insulating_panel

    10. Insulating Render

    This is a fairly new material to the UK market, and is a render which is insulating throughout its thickness. It’s applied like a render and doesn’t need vapour barriers or special membranes. It is a mixture of special earth and other ingredients, such as a cork aggregate, which would need to be applied to a thickness of around 100mm or more and can accommodate an uneven existing surface.

    DiathoniteInsulatingRender

     

    Find Out More

    Untitled

    Follow Brian Murphy on Twitter

    Transcript

    Download a transcript of the interview with Brian Murphy.

    Please Connect With Me