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  • HPH305 : Building a Passivhaus with cross-laminated timber – with Mick Woolley

    HPH305 : Building a Passivhaus with cross-laminated timber – with Mick Woolley

    Mick Woolley explains how the use of timber was a key element of his award-winning Passivhaus bungalow.

    Interview with Mick Woolley

    For the last two years, Mick Woolley has been living in his Larch Corner Passivhaus which was the Small Projects winner in the 2021 UK Passivhaus Awards.

    His self build journey began following the loss of his wife. He had long held an interest in self building and took the attitude “what could possibly go wrong!”

    To watch the documentary about Larch Corner go to PassivhausSecrets.co.uk

    He broadened his search area

    Initially beginning his search in the south east of England to be closer to his two sons in Surrey, Mick found a lovely plot, surrounded by a vineyard, and just 30 miles away from them. But despite the proximity, it had taken an hour and a half to get there and was £450,000 before he’d even knocked the existing bungalow down. It was at that point he decided to abandon his search in the south east and opened up to looking at sites as far afield as North Wales and Cornwall.

    They made changes to the planning designs

    Mick saw a plot on RightMove, that seemed to be in a pleasant village location at the northern tip of the Cotswolds. Close to a National Trust garden and Stratford upon Avon, he felt he would be able to find enough to do in the area and was surprised when he managed to purchase it for around the guide price at auction. It came with planning permission for a single storey Passivhaus with a design that he admits probably didn’t appeal to everyone, and is why he thinks there wasn’t more competition in the bidding.

    Although not put off by the design, he was sceptical of its Passivhaus credentials and enlisted Mark Siddall of LEAP to re-work the plans. He did however want to keep it a bungalow to make it accessible for a family member who uses a wheelchair, but also because it future-proofed it for him too.  

    The original design had a lot of corners so they removed some of these and also had to raise the roof to ensure there was adequate head height for insulation. They swapped the entrance hall and study around to ensure a better flow into the house, and took out the many corner windows from the plans. Mark instead designed an arrangement of windows that came in 2 sizes: smaller ones for the bathrooms and bedrooms, and larger windows with seating elsewhere.

    Timber was an important element of the design

    Mick wanted to build using Cross-Laminated Timber (CLT), as much for the visual impact it provided inside as for its structural qualities. The bungalow uses 17 sections of spruce timber, which have 6 layers, are edge-glued, and don’t require an airtight membrane around the outside.

    The roof came with a cassette of insulation in it so the structure went up in two days, and had an airtight wrap over the top by the end of the third day. The walls are made of an I-frame structure with blown-in wood fibre, giving a thickness of around 600mm and a U-value of 0.1.

    The exterior of the bungalow has larch cladding.

    The foundations were pre-cut to size

    The building has a Jackon XPS foundation which was pre-cut to the required size and slotted together, with an XPS upstand that locked into the perimeter. This created its own formwork for the concrete pour.

    The flat roof has a camber of around 5 degrees for shedding water. On top of the insulation is a cold roof section of ply and bitumen that provides the finishing structure on which to put the green roof. Mick says he checks up there from time to time just to check that seedlings for trees and other unwanted plants haven’t blown in and taken root!

    He was keen to be hands-on

    With Mick being on-site throughout the build process he was keen to get involved in any way he could, so one task that he took on was the airtightness taping. His top tip for getting it into the corners is to ideally bend the tape in two in order to push it in and get good contact right the way through the junction.

    The straight lines of the 17 sections of CLT only took an hour to do, but all the other joints around the doors and windows took a lot longer!

    Mick employed Alan Clarke as his M&E engineer and he carefully designed the ventilation system so it could go through cupboards and be kept out of the way, but still accessible if needed. The full design with all of the MVHR kit was supplied as a single delivery, and Mick took on the installation of the pipework himself. Not having any experience of doing something like that, he did find it took him a very long time to put together!

    There is around 140 square metres of floating floor, which was designed to be laid to flow through without any junction strips at doors. His builder Andy took time to work out the geometry to ensure that boards were centred and wouldn’t end up with slivers at the edges, which Mick was then able to lay.

    Always make space for storage!

    Although Mick was adamant that he wanted to use CLT, he now realises that he could have been more efficient with materials and created the timber finish that he was looking for by using large sections of three-ply timber.

    If he were to do the build again, he would probably opt for a two-storey building, though still keeping a downstairs bedroom. He says that the UK housing stock is generally fairly deficient in terms of providing for the elderly and those with mobility problems, so designing at least one bedroom downstairs is really important.

    Mick says that going for a two-storey design would improve the form factor and use a lot less insulation. It is also more efficient in having less foundations and roof.

    Lack of storage space is often a real problem in typical new build homes, but Mick is delighted at the amount of space they designed into his home, including a large storage wall. He also has a double garaged sized shed, although this is currently housing lots of off-cuts of CLT and three-ply materials that are waiting to find a home!

    He emphasises why it’s always a good idea to build into the loft as that’s also potential space that can be used for storage.

    Images copyright Mark Siddall LEAP

    Find out more

    To watch the documentary about Larch Corner go to PassivhausSecrets.co.uk

    Check out the website of LEAP

    Follow Mick Woolley on Twitter

    Follow Mark Siddall on Twitter

    Please connect with me

    Subscribe, rate and review the podcast in iTunes

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  • HPH264 : Your forever home lifestyle – with Mark Siddall from LEAP

    HPH264 : Your forever home lifestyle – with Mark Siddall from LEAP

    Mark Siddall from LEAP explains his framework the ‘Forever Home Lifestyle’ and how he uses it with his clients.

    Interview with Mark Siddall

    Mark Siddall is an architect with a passion for designing low energy buildings. Recently he’s taken a look back at his last decade of projects and thought about the things that clients have asked for and what their cumulative thinking is. He’s used this as a starting point to come up with his ten point framework for a forever home lifestyle.

    Preston Springs Passivhaus

    Contentment and character

    The first step on Mark’s framework is to think about contentment in the right ways and in different timeframes.

    When we think about contentment it is usually in terms of an actual design and, largely the character of the design. That can be broken down into the interior and the exterior. Externally there might be constraints by planning related considerations, and internally it’s more about budget and aspirations that can transfer into elements of style.

    “The sense of wellbeing that comes from being content is incredibly important and it means different things in different contexts. It’s an opening into a deeper level of conversation that will allow people to make a more robust appreciation of what they actually want.”

    Convenience

    Once emotional constraints have been considered, then there’s convenience. This covers the room layout, the accessibility around the house, and the way that it supports and compliments our lifestyle. This means thinking about the flow, the circulation spaces, the function of the rooms, the furniture and fittings that come with that.

    When Mark goes through the process of developing a brief, he will conduct a survey of what people do and don’t like about where they’re currently living, to determine how important a particular factor is and what the implications are.

    “They’ve obviously selected to live there; they’ve made those choices and its informed their understanding. So, if they want to then move to the next level and improve their quality of life, how can we take the best of what they’ve got and then top it and make it even better?”

    Control

    Having control over your own comfort is very important, and ties in to an emotional criteria. That can be down to opening or closing windows, controlling heating systems, creating a healthy environment through air quality, noise levels and controlling sunlight levels to prevent overheating.

    Confidence

    This is about how confident a self-builder / homeowner can be about what they’re seeking to achieve. Mark says that his building performance evaluation provides evidence-based reassurance to support and justify decision making. Using PHPP is part of that process for Mark, as without it you wouldn’t get the quality control that is required for delivering buildings that the performance predicted. He says there are no definitive answers from this, but that he is there to provide guidance to help clients make their own informed decisions.

    Community

    Community is important when putting your 25 or 50 year framework in place. It is about thinking of whether you want to live in isolation, or within a hamlet or town setting for example, and considering what kind of support you might need in the future or can offer yourself. That can also lead to thoughts about co-housing or community-led housing which might compliment different lifestyles.

    Connection

    A natural progression is to then consider connection and accessibility of amenities and looking ahead to whether you will be living in an area that can support your needs in older age. These thoughts then inform what kind of site you’re looking for, and whether you’ll be able to walk or cycle safely, or if it’s a walkable distance from bus stops taking you where you might need to go once driving is no longer an option. Mark says clients will often have an emotional connection to a site because of the remote location or wonderful views, without thinking about how well it will serve them in the future.

    Larch Corner interior

    Futureproofing

    This looks at getting the right kinds of spaces and also thinking about how things might change over time. It also ties in with low-energy housing and Passivhaus, where energy bills can be fairly inconsequential, thus offering a level of financial independence once a mortgage has been paid off.

    There is sense in designing the building so that in the future it could be adapted if mobility was a problem, by making level flooring, having the right things in the walls ready in case handrails are needed, and having access through the house for wheelchairs or walking frames.

    Financial Peace

    As well as thinking about the freedom from energy bills, this is concerned with budgets and how to stick to them.

    Even before Mark is instructed as an architect he will do a piece of work using his experience of previous similar builds to give a rough range of costs. This can give the basis for conversations to be had around what might be achievable in terms of what the size and nature of the house might be, before even getting into the design stage. It is however only a starting point.

    “That means that informed decisions can happen before there’s a design taking place. And that’s really important. That way we understand what we’re designing because the budget informs the brief incredibly and we’ve got to design within those budgetary constraints.”

    “I can provide a bracket somewhere between this and that, at a very formative stage. There are things that I can do as an architect that can help to stack the odds in our favour of it being more cost effective in terms of the compact form and thinking about things like that, but at the same time, there’s that reconciliation and there’s always the changing marketplace which means that we always can find that there is going to be some movement and further conversations to have. It’s not done once and then never looked at again.”

    Faithful custodian

    Mark sees himself as an architect and also custodian of the built environment. He says that sustainability can seem broad and rather distant, but once his clients see themselves as custodians too they have positive and constructive conversations that develop and benefit their designs.

    “So, as a custodian, we’re thinking about how we can address climate change, how we can reduce carbon emissions, how we can live more sustainably, how we can help repair and remediate damage to the ecology and biodiversity. And how we can then start to use the buildings that we design collaboratively; how they can then start to do something restorative to improve the quality of life and at least impact less than may have been the previous case.

    There are all sorts of different perspectives about what that might mean and how it relates to their lifestyle, and that’s all fruitful conversation which helps enrich my understanding and I can then pass that on and enrich somebody else’s.”

    Abundant free time

    This asks how the house will support and provide a framework for having an abundance of free time and improving quality of life.

    In simple terms it can be about providing opportunities to work from home and avoid a long commute. It also thinks about diet and fitness and keeping physically and mentally active.

    Find out more

    Visit the Forever Home Lifestyle website

    Find out more about LEAP

    Follow Mark Siddall on Twitter

    Transcript

    Download a transcript of the interview with Mark Siddall

    Please connect with me

    Subscribe, rate and review the podcast in iTunes

    Rate and review the podcast on Stitcher

    Like our Facebook page

    Follow us on Twitter

  • HPH044 : Avoiding the Risks of Poor Ventilation – with Mark Siddall from LEAP

    HPH044 : Avoiding the Risks of Poor Ventilation – with Mark Siddall from LEAP

    Mark Siddall from LEAP (Low Energy Architectural Practice) explains the circumstances under which poor ventilation can occur and why the control strategy becomes increasingly important the more airtight the building is.

    Mark-Siddall

     

    Interview with Mark Siddall

    Mark Siddall trained as an architectural technologist before training as an architect.

    He established LEAP in 2011 and he’s also written over 30 articles and papers on building performance and Passivhaus. Get free access to his research.

     

    Poor Ventilation Can Lead to Poor Health

    In very poorly ventilated buildings mould and fungus can grow on the surfaces and in carpets, etc. This can cause respiratory problems for the occupants.

    Humidity can also have an impact. In a low humidity environment immune systems can become depleted and there may be increased incidents of asthma. If humidity gets too high then dust mites can populate a home quite quickly and that can increase the likelihood of asthma, too.

     

    Occupants Only React When They Perceive a Problem

    Mark says there’s a reasonable amount of evidence to suggest that unless occupants perceive a problem with ventilation they just get on with their lives.

    In older homes that are particularly leaky anyway few issues tend to arise. However the more airtight a building is, the more important the control strategy becomes (whether it’s a natural or mechanical ventilation system).

     

    There Are Four Different Ventilation Strategies

    Within the (UK) building regulations there are four primary systems:

    1. Windows with trickle vents and intermittent mechanical extract ventilation.
    2. Windows with trickle vents and passive stack ventilation.
    3. Continuous mechanical extract ventilation.
    4. Mechanical ventilation with heat recovery.

     

    Mechanical extract ventilation with trickle vents is by far the most common ventilation strategy (in the UK) but with a focus on lower energy buildings there is a move towards mechanical ventilation with heat recovery (MVHR).

    MVHR-good-practice-550px A ‘good practice’ installation of MVHR

     

    Mechanical Ventilation Can Get Switched Off Unnecessarily or Because of Problems

    Mark describes some of the circumstances that have led to occupants switching off their mechanical ventilation systems. For example, if people are conscious of their finances they can perceive that a mechanical ventilation strategy is more costly. This need not necessarily be the case if it’s a well-designed system with some low energy fans.

    In a similar way people who are environmentally aware might think that by switching off the ventilation system they are reducing their carbon emissions. 

    Another trigger can be when the ventilation system is too noisy. 

    Unless there is a natural ventilation strategy, switching off the mechanical ventilation will have an impact on the indoor air quality.

     

    There Will Always be Some Noise Associated with the Ventilation Strategy

    Whether it’s a natural ventilation strategy through trickle ventilators or a mechanical ventilation system there is likely to be some level of noise.

    The question is really what should be considered an appropriate level.

    Mark says: “The World Health Organisation defines an appropriate noise standard as being 35dBA . Then for mechanical ventilation systems there’s a range of different acoustic targets that you might try and conform to depending on whether you’re referring to UK Building Regulations and its recommendations or whether you’re referring to good practice.”

    There is research suggesting that the World Health Organisation noise level may not be appropriate for mechanically ventilated buildings.

    Duct-Attentuator-400px

    A duct attenuator

     

    Attenuators Can Reduce Noise

    Similar to an attenuator for a car exhaust there are attenuators for ventilation systems.

    They can be situated at appropriate locations within the house to prevent break out noise from the ventilation system into the rooms and also to help reduce the risk of noise transfer between rooms.

     

    Is There Drier Air Inside Buildings with MVHR?

    Mark explains why some of us might perceive drier air inside buildings that have mechanical ventilation with heat recovery.

    If it’s cold outside, for example zero degrees, then the air can only hold so much moisture. When that moisture is brought inside the building, its temperature is raised and the relative humidity of that air drops. It’s that dry air that is then created that might be perceived through dry noses, dry eyes and the likes. 

    It’s important to note that this is irrespective of whether it’s a mechanical system or a natural system, assuming that they’re both supplying the same amount of fresh air.

    Mark continues: “What you tend to find though is that where there are reports of drier air it tends to be in buildings that have got more mechanical ventilation systems and that is because, I would argue, the systems are constantly providing that ventilation whereas natural ventilation in itself is inconsistent.“

    Apex-Acoustics-550pxApex Acoustics doing some Passivhaus sound testing 

     

    Clocks and Fridges Are Often Noisier than Ventilation Systems!

    Mark reflects on some research he was doing with Jack Harvie-Clarke from Apex Acoustics, where they were trying to identify whether there were potential noise issues from ventilation systems.

    After sound testing at the Racecourse Passivhaus Development they found that the alarm clock, kitchen clock and the fridge were noisier than the MVHR.

    This is exactly what they were hoping to find and it means that the system had been designed properly, the contractor had completed the work appropriately and the system had also been commissioned well.

     

    The User has Perfect Control Over the Ventilation  

    In a Passivhaus – just like any other build – it’s down to the user on how to operate the building. Different fan speeds allow the occupant to control the rate at which the building is ventilated and of course the windows can be opened at any time of the year!

     

    External Noise or Concerns Over Security Can Deter People from Opening Windows

    Mark also points out that despite having tilt-and-turn windows, which are arguably more secure, some occupants at the Racecourse bungalows were still reluctant to keep windows open on summer nights because they perceived it as a security risk. This could therefore make the building more likely to overheat.

    Similarly there are associations between noise and ventilation, so people keep their windows closed up to the point that the threshold of discomfort becomes too great and then they’d rather put up with the outside noise and open the windows!

    Capped-Ducts

     Capped ducts

     

    Rigid Ductwork is Preferable

    If there are kinks in the ductwork then a higher fan power will be necessary to get air to the right places. This in turn leads to more noise and using more electricity energy.

    Rigid ductwork therefore ensures that there are no kinks and bends.

     

    Keep Duct Runs Short

    Using long duct runs not only means more material is being used, but there’s more labour and more cost.

     

    Prevent Ductwork From Getting Dirty During Construction

    Having dirty ductwork can lead to occupants getting drier eyes, sore throats and other things that are associated with Sick Building Syndrome.

    So it’s important to ensure that the ductwork is clean when it’s designed and constructed because by far the most dirt will get into the system during the construction process.

    Dirty-ductwork

     Bad practice – dirty ductwork!

    Mark even got Wolfgang Feist to take a look inside his ventilation heat recovery system! It’s been in place for 10 years and he reported back that it’s as clean as the day it was finished.

    As long as no dirt got into the system initially and the filters have been changed as required, there should be no cause for concern.

     

    One of Mark’s Projects: Steel Farm

    Mark Siddall_Passivhaus Architect_LEAP_Steel Farm7_Passivhaus_Northumberland

     

    Find Out More

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    Transcript

    Download a transcript of the interview with Mark Siddall.

     

    I’ve Been a Guest on a Few Podcasts Lately!

    Home Style Green: I chatted with Matthew Cutler-Welsh about my first year of research at House Planning Help and my e-book Why Most People Don’t Build Energy Efficient Homes.

    The Construction Marketing Podcast: Pritesh Patel and I were able to geek out on internet marketing! So if you’re looking to take your first steps into content marketing, there’s loads of great information in this episode.

    Slender Safari: I met Shey Harms at the New Media Expo in Las Vegas, USA. After I had some issues with American portion sizes she asked me onto her weight-loss podcast to compare and contrast British and American cultures when it comes to food.

     

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