Contact →

Tag: fabric first

  • HPH383: A beginner’s guide to creating a comfortable home – with Andy Mitchell

    HPH383: A beginner’s guide to creating a comfortable home – with Andy Mitchell

    Andy Mitchell, Managing Director of 21 Degrees, explains what factors influence human comfort and how we have tried to make our homes more comfortable through the years. Embracing building physics has been a turning point and while we have the knowledge and skills to create healthy and comfortable homes today, it’s still not the default approach. So Andy outlines the options available to get yourself into a better home.

    Interview with Andy Mitchell

    Andy Mitchell is the Managing Director of 21 Degrees. Engineering runs in the blood as he comes from a family of engineers and he has always been fascinated by houses and buildings, even considering architecture as a possible career path at one stage. Studying product design at A-Level he then became interested in company structure and business. His first significant role in sustainability was at a company called Natural Building Technologies in the early 2000s, where there was a focus on healthy bio-based materials. Today he heads up 21 Degrees, a company which supplies key technology to homeowners and architects enabling them to build more efficiently, and generate and store energy.

    In this podcast Andy explores the concept of comfort and explains why we can do much better when it comes to creating a comfortable and healthy home in which to thrive.

    We can define a comfortable temperature

    While we might think that we are all different and therefore prefer to live at different temperatures, that is not true. We can define a comfortable temperature range because of our physiology.

    “Any human being, no matter where they are on the planet is most comfortable between 20°C to 22°C. The reason is simple. If the temperature is higher, your body has to work harder to keep you cool; and if it’s colder, your body has to work harder to keep warm.”

    The body doesn’t cope well under 15°C

    Below 15°C humans have to work hard to keep warm. At 9°C or less, it’s a matter of survival.

    How active we are, alters what we perceive as a comfortable temperature

    If we’re engaging in a lot of activity, such as cleaning our homes, we are generating heat and keeping ourselves warm, so may desire a cooler temperature. Alternatively, if we are working at a desk and sedentary then the reverse is true and we may want it to be warmer. Generally speaking the impact of this is plus or minus 2°C.

    Putting on clothes is another dynamic

    You only need to look to the Inuit in parts of Greenland to understand what an impact clothing can have. They could survive in subzero temperatures. The downside is that their clothing was bulky and would limit the activities they could perform. Any clothing will go some way to making us feel warmer because it’s trapping the body’s heat and slowing it down from moving away from the body. It would be the same effect sleeping under a duvet. The duvet is insulating your body heat.

    Relative humidity levels impact our health and comfort

    Humidity, or the level of moisture that’s in the air relative to the temperature, has an impact on comfort. The warmer the air, the more moisture the air can hold. And generally, humans are most comfortable at 50%, plus or minus 5%. It’s quite hard to fix humidity levels but between 40-60% is seen as a healthy range. If the levels exceed 70% regularly then these conditions can lead to damp and mould, which are damaging to human health. Below 40% is not good either and could cause respiratory issues.

    Lowering the temperature to save money will create an unhealthy environment

    Andy explains that it may be a false economy to turn down the thermostat in winter to save money or reduce fossil fuel usage. This is because as you drop the temperature the relative humidity goes up.

    “If you had a temperature of 22°C and the relative humidity was 50%, and you dial the temperature down to 18°C, you’ll actually increase the relative humidity to 64%… You’ve made yourself slightly more uncomfortable because you’ve increased the relative humidity.”

    With poor ventilation, which is common in many British homes, the relative humidity may have been closer to 55% anyway.

    “If we’re closer to 55% relative humidity that really starts to get interesting, because if you dial down from 22°C to 18°C, you’re at 73% relative humidity and that starts affecting your health. For example, dust mites proliferate above 70%, eczema and asthma are a direct consequence of allergic reactions to dust mite poop. You’ve also got issues with mould growth.”

    Radiant heat also plays its part in comfort

    In addition to temperature and humidity, radiant heat plays a significant role in how comfortable we feel. Andy shares a couple of examples of when you might have experienced this.

    If you’re taking a stroll on a sunny day and a cloud goes in front of the sun, you might notice you suddenly feel a bit cold. The air temperature hasn’t changed. What’s happened is the radiant heat that’s been hitting your body has dropped because it’s been obscured by the cloud.

    Radiant heat is also absorbed and emitted by surfaces in our homes such as furnishings, walls, windows, etc. So the temperature of those surfaces will have a significant impact on your comfort levels.

    Our homes have got better over time!

    Over the centuries we have turned to fires to keep us warm. In Victorian times there were open fires, which were extremely inefficient because most of the heat went straight up the chimney. However, the rooms felt more comfortable because of the radiant heat being absorbed and then given off from walls and furnishings, etc.

    “The big, winged armchairs that we perhaps thought were to stop granddad falling out of his chair when he fell asleep were actually to keep the radiant heat in… It captured that heat that was being radiated out from the fireplace in the room.”

    With the advent of cheap energy, such as access to North Sea gas in the UK, we could pipe fuel straight into our houses. Burning this in boilers, heating water and then piping it around radiators was a big leap forwards. Although fossil fuels are energy dense and have been an easy source of fuel, their emissions have contributed to global warming and we have nearly exhausted the supply in a few decades. 

    Indoor temperatures have been increasing

    Back in the 1970s, the average temperature in a British house in winter was 12°C – 13°C. These days, it’s probably closer to 18°C – 19°C. Andy says that figure could be impacted by a number of people who are in genuine fuel poverty. In other words, they find it unaffordable to heat their homes. One reason for this is that the UK has a large amount of old and leaky properties.

    Leaky homes are just about tolerable in a mild climate

    Andy says that the UK has the most inefficient housing stock in Europe. While Germany is on a latitude further South and might face temperatures of -10°C, a British winter is milder and more akin with Italy. Therefore with a few token measures, such as double glazing, and cheap energy, we have got by.

    “Sadly, I think we focus more on basic survival and then toleration, rather than what makes for a great home? What really does give us that extra level above survival, so that we can thrive? Again, to me, this is very much what comfort brings… It means you can be more productive in terms of your work. You’ve got higher levels of energy, because you’re not using it to keep yourself warm or cooler.”

    Sensing a ‘muggy’ environment indicates pollutants have built up

    As we live in our homes the indoor air is changing. We exhale CO2 and generate moisture from our activities. Relative humidity builds up and there may even be VOCs given off from furniture, paints, etc. Our instinct is to open a window, which Andy says will solve the problem.

    “By opening the window, you purge the air to the outside, because generally warm air will move to the outside, particularly if there’s a bit of cross ventilation, and as a result, arguably, the temperature will be dropping a bit. But if you don’t leave that window open for too long you’ll have a complete air change, and the air that’s come into that room, because the walls and the fabric are warm, to some extent, that air will warm up. And what was outside air, which was probably around about 70% relative humidity, would have dropped down to around about 50% relative humidity, and suddenly you feel much better again!”

    The problem is this purge is needed regularly and is hard to manage. More often than not there will be a drop in internal temperature.

    In winter another source of discomfort is draughts, where you’re sensing changes in air temperature. For example, if you stand near windows that are single or double glazed, they are colder than the internal air temperature so you will feel the heat moving away from your body.

    You may also experience stratification of the air and this heat differential causes air movement, which in turn can make you feel uncomfortable. For example, your feet can feel colder than your torso. You may not even be aware of it.

    We have got to grips with the physics of buildings and know how to build better homes

    In the past we have simply put our buildings together without worrying too much about how effective they are, focusing more on aesthetics. However, there is an approach that works and has been around for over thirty years. Dr Wolfgang Feist and the team at the Passive House Institute decided to look at things from the first principles and get a holistic picture. This led to the development of the Passivhaus standard, which is a formula that anyone can follow to make a building that works. Core principles include insulation, airtightness, high performance components such as windows and doors, reducing or eliminating thermal bridges, introducing mechanical ventilation with heat recovery, and orientating the building towards the sun.

    Andy points out some of the benefits. For example, in a Passivhaus the temperature of the surfaces will be plus or minus 3°C of the air temperature. It will be draught-free and the heat loss will have been reduced significantly. The introduction of mechanical ventilation with heat recovery also means there’s constant fresh air coming into the building, but the heat from the outgoing stale air is retained. And this is a way of controlling the relative humidity, too.

    So building or buying a certified Passivhaus is one way of ensuring you have a comfortable and healthy home.

    Buying a new home doesn’t necessarily mean it’ll be efficient or healthy

    Although the Passivhaus standard was developed decades ago, the learnings and methodology have not been incorporated into the building regulations. Therefore there is still a performance gap in most new buildings, where the design intent is never reached in the completed building.

    We are all responsible for the status quo

    Not only do we as homeowners tend to accept the status quo rather than demanding higher standards, but architects, designers and contractors struggle to adopt new strategies. So sometimes the drawings fail to give enough detail, particularly around things like airtightness or thermal bridging, which is just where you’ve got surfaces or materials joining together, and you can get additional heat loss that you wouldn’t do through the principal wall or roof or floor areas. It can be the contractors on site, who don’t fully understand the goals of the project and might cut through a membrane not realising the impact of doing this.

    Then there’s the building standards themselves. The reality is the building standards stop at the point of design. Currently there is no ‘as-built’ check of the performance.

    “So the performance standard stops at the design stage because you demonstrate through something called SAP, Standard Assessment Procedure, what is the heat loss from this building based on the building fabric. It’s pushed through a calculation. Effectively, it says yes this fabric will pass, and that’s where the testing ends. There is nobody from Building Control actually measuring the heat loss of the building once it’s occupied.”

    The choices are getting better

    Andy believes that building to a performance standard above and beyond building regulations is becoming more common. We’ve mentioned the Passivhaus standard but there’s also the retrofit standard EnerPHit. The AECB New Build standard is another option, which is slightly easier to reach, but has the same rigorous building physics approach.

    Building your own home allows you to get what you want

    When people are building or commissioning their own homes they almost always strive for higher standards. And doing a self-build project is not quite as onerous as it might seem, with more and more help available. Andy says we build about 5% of our homes in the UK this way, or 15,000 homes a year, which is equivalent to the output of the fourth largest volume house-builder in the UK. This is a good start but to put it into perspective Germany deliver around 50% of their homes as self-build. So maybe it’s not surprising that these standards have taken time to be adopted.

    It is possible to improve the performance of an existing property

    If building new or buying from the open market is not proving successful, then there is another option. Existing homes can be retrofitted to a performance standard. It is often harder, and some homes will be more challenging than others. For example, how the building is orientated is something that is hard to change. There are also significant costs for a deep retrofit.

    “The more complex a building is in its form, often the more challenging it is to reduce the heating requirement, the heat load. You can still go a long way, though, to improve airtightness and therefore comfort levels but you might not achieve the same low energy results that other more simpler forms of building can.”

    On a phased retrofit, improve the ventilation first

    Doing a retrofit in one hit often makes life easier, but not everybody is in a position to do this. So another option is to do a phased retrofit. The most important part is to have a comprehensive whole house plan at the beginning.

    Andy says that a good first step is to improve the ventilation of a property because that will give you cleaner, fresher air, with more controlled levels of relative humidity. While it may cost a bit more in heating initially until you have reduced your heat loss, you can immediately benefit and also reduce the risk of damp and mould building up in places where you have improved the fabric but have not improved the ventilation yet.

    The average family home produces up to as much as 15 litres of moisture a day that goes into the air. This evaporates from our bodies when we’re sleeping or walking around the house. Moisture is also generated when we’re cooking, taking a shower or doing the washing, and it has to go somewhere.

    So after the ventilation has been addressed, the next phase might be looking at improving the airtightness and replacing the windows.

    Adding insulation changes the physics of the building

    When you apply products to your building, you are changing the physics of the building. So if you apply a piece of insulation to a part of your property, you are changing what was there before, and if it hasn’t been well thought through you could end up with unintended consequences. Andy gives an example of fitting closed cell insulation internally which is principally a bad idea because you are likely to trap moisture in the wall. This interstitial condensation could ultimately lead to the building fabric being damaged or breaking down, or potentially creating mould pockets, which then can affect the quality of the air in the room.

    Mechanical ventilation must be designed well

    There are various ducted ventilation systems on the market but they have to be designed well to be effective.

    “The ducting design, for example, in MVHR is far more important than the actual unit that you plug into the end of it. A decent fan and heat exchanger is important, but you can have the best MVHR unit on the market and you plug it into poor ducting design, and you’ll just have a poor system. Whereas you could have an average MVHR unit and plug it into some effectively designed ducting, and you’d have actually a very good system.”

    MVHR can be useful if the outdoor air is not clean

    If the external air quality is poor, such as on a busy road, or if there’s a lot of pollen that is having a particularly bad effect on a hayfever sufferer then a fully vented, ducted system often takes the air through filters. So you can filter particulates from outside and stop them coming into the house.

    Making a home more healthy and comfortable shouldn’t be about payback

    When people go on holiday they don’t look for the payback on their holiday! People are also prepared to spend a lot of money on a kitchen. However, when you tackle a big project that will improve health and save money on bills, they suddenly believe it should pay for itself.

    Treat homes as homes, not as assets

    It would be good if we moved away from viewing houses as assets, and actually looked at them as a way to help us live effectively.

    Andy is tackling his own retrofit

    We are all on a journey to creating better homes for ourselves and our families. And that includes Andy! He is making improvements to his Victorian home with a phased approach.

    “You do a measure to your own property, and you still find yourself being quite impressed! So we live in a Victorian property, and half of the floor of the property is a cellar. The other half is solid floor, and we insulated in the joists of effectively the cellar part, and that made a significant improvement. And then the following year, we had an airtightness membrane installed underneath the joist and the insulation, and that made as significant, if not more significant an improvement in both the thermal performance of that room.”

    Andy believes that most of us become complacent with our homes when we actually have the opportunity to enhance our lives.

    “As human beings, we have this incredible gift of adaptation. The problem is it’s also a curse, and we just tolerate an awful lot of rubbish. If our awareness was increased and we could begin to learn what is possible, particularly in terms of how we can live within our built environment I think the change for our welfare, both as individuals and society in general, would be significantly impactful.”

    Find out more

    21 Degrees

    Why MVHR maintenance and servicing is important

    What makes a well designed MVHR system?

    How do you specify high performance windows?

    Two radical retrofits that use an internal wall insulation strategy

    Low energy barn conversions

    Transcript

    Download a transcript of this episode.

    Please connect with us

    Subscribe, rate and review us on Apple Podcasts

    Follow Ben Adam-Smith on LinkedIn

    Follow Ben Adam-Smith on Bluesky

  • HPH280 : A beginner’s guide to the Passivhaus Standard – with Jon Bootland

    HPH280 : A beginner’s guide to the Passivhaus Standard – with Jon Bootland

    Chief Executive of the Passivhaus Trust, Jon Bootland, explains the processes and benefits of building your house to the Passivhaus Standard.

    Interview with Jon Bootland

    When Jon Bootland finished his university degree he began his employment first as a building services designer, and later working on good practice for sustainable low energy buildings, now with nearly 30 years experience. He has also been involved with the Passivhaus Trust since it was formed back in 2010. With initially very slow progress since the first Passivhaus was completed in the UK in 2010, numbers are now increasing rapidly at around 1,200 completed buildings (of which around 200 are individual owner-occupied homes), with another thousand already in the pipeline.

    Carrowbreck Meadow – Image copyright Jefferson Smith

    There’s nothing hugely complicated about Passivhaus

    The origins of Passivhaus come from Germany, where the physicist Wolfgang Feist wanted to find a way of making sure that high performance buildings actually delivered on their claims, and performed the way that they were designed to do.

    “It’s all about building physics. There’s nothing hugely complicated about it. It’s just what do we need to do to actually make it work and do what we said it was going to do.”

    High in comfort levels, low in energy use

    The fundamentals of a Passivhaus are:

    Insulation – This is an important part of reducing the energy required to heat the building. A typical Passivhaus might have up to 30cm of insulation, meaning that the walls will be very thick.

    The building fabric and airtightness – The other parts of the building will also need to have a very high performance. Windows for example will need to be triple glazed with good quality frames and careful detailing about how they fix together. The airtightness of the building is important with the aim being to stop draughts coming in and heat leaking out.

    Ventilation – Because the building is now free of draughts, attention then needs to be paid to how to ventilate it. A mechanical ventilation system is used (MVHR) to bring fresh air into the building, while recovering the heat from the outgoing air.

    As well as dealing with keeping the house warm in winter, Passivhaus formulae also look at the sun and other heat sources coming into the building and how the ventilation and insulation can work to keep it cool in the summer.

    Old Holloway – Image copyright Juraj Mikurcik

    Have a Passivhaus expert in your team

    Jon says that building a Passivhaus is harder to do than a normal house, but that doesn’t necessarily mean you have to employ a team of specialists. He would however recommend having someone in your team that does have Passivhaus training, and preferably experience. It doesn’t have to be the builder, but could be the architect or a consultant.

    The Passivhaus Planning Package does the calculations

    You will need someone who knows what they’re doing to fill in the Passivhaus Planning Package (PHPP) and work out the answers to the calculations with you. It is a tool that takes a holistic approach to making all the elements work together, to make sure you end up with a building that has the performance and comfort that you are looking for.

    There are benefits to having certification

    PHPP should be used right from the beginning to look at the size and shape of the building, the window locations, balconies or anything else that might penetrate into the building etc. A certifier is able to check what is being put forward and advise on whether what you’re suggesting is actually going to work in the way it is intended.

    Without having a certifier on board you will not be able to call it a certified Passivhaus, which does have some value in being able to sell the project. Certification is the best way of ensuring that your building will meet the required standards and provide the comfort and energy performance that you are looking for. If you’re not planning to use a certifier, then Jon recommends ensuring your team of architect, builder and consultants have plenty of Passivhaus experience between them to give you confidence it will perform as intended.

    There are health and cost benefits

    Jon outlines some of the key benefits of a Passivhaus:

    Lower energy bills – The extra insulation and airtightness means less heat is escaping from the house, and therefore less energy is needed to heat it. Typical heating bills for a standard sized Passivhaus might be around £100, compared to several hundred for a non-Passivhaus equivalent.

    Health benefits – Jon says there are research projects planned in the next few years looking into this, but there is still plenty of anecdotal evidence from occupants talking about the health benefits of living in a Passivhaus. As well as thermal comfort, the air that comes in can filter out air pollution and pollen, and people have reported improvements in asthma conditions. The mechanical ventilation also reduces moisture levels in the building which prevents condensation and mould.

    Some construction methods will be harder than others

    Jon says that although you could achieve Passivhaus with any construction type, it will be harder to achieve with brick and block for example than with timber panels. Although it’s possible to do, it will just need to be approached differently.

    The extra outlay is money well spent

    Jon uses social housing to get comparable benchmarks for how much more a Passivhaus will cost to build over a standard form of construction. Typically the additional cost of building a Passivhaus will be around 4-8% higher. Jon says that probably half of that is just on better quality building, which actually should be applied to all new buildings anyway, regardless of whether they’re Passivhaus.

    So on a £200,000 – £400,000 build cost, that’s likely to add on just £8,000 – £16,000 extra.

    “So, say you’re going to get a much better quality building that will make you more comfortable, more healthy and will perform better for 50, 100 years or more, it’s a very small amount of money in my book and it’s a much better way to spend your money than on a super flashy designer kitchen.”

    There are ways to keep costs down

    The shape and form of your building is crucial in keeping the costs down. Adding on multiple wings, outlying parts, differing floor levels, balconies additional roofs, lots of corners and odd shapes, will all make it more difficult to make a Passivhaus work, and will be more costly.

    Jon wouldn’t recommend everyone try and build a square box as being the answer, but the closer you aim to a square box shape the easier it is to achieve Passivhaus.

    Another way to keep costs down is to bring in your Passivhaus expert as early as possible. Don’t wait for the design to be finished and then call them in to do the calculations, but involve them at the design stages to help develop the building shape, window sizes and locations etc.

    Multiple heating sources are not needed!

    Jon explains that it can be challenging mentally to think of a house not needing multiple heat sources in it, but really they’re not needed.

    Commonly though, people might put a radiator by the front door so that as you walk in there is a perception of extra warmth, while your body adjusts from the cold outside to the comfortable 20-21 degrees inside. A heated towel rail in a bathroom is also quite popular.

    The design needs to minimise overheating risk

    With homes becoming more energy efficient, the risk of overheating in the summer is becoming more significant and has to be planned for.

    The main source of heat coming into the house in the summer will be from the sun, mostly in the late afternoon and evening. To stop the heat coming in without losing the views, Passivhaus buildings will often have some kind of shading or overhang on the west or south facing walls which keeps out the heat until later in the evening when the temperature drops.

    There are also other heat sources to take into account such as the occupants and appliances, which heat the house slowly during the day. This data also feeds into PHPP to calculate how much heat will need to be taken out of the building to keep it cool. This can be done using the mechanical ventilation, or by opening the windows, particularly overnight. The temperature fluctuation in a Passivhaus will only be a few degrees, compared to 10-15 degrees in other houses.

    “But the extra insulation and the extra performance of the windows, the doors and so on helps in the summer. Just as much as it helps in winter in keeping the heat in, in the summer it keeps the hot air out.”

    The Passivhaus Trust oversees the standard in the UK

    The standard was invented and developed in Germany, but in the UK it is looked after by the Passivhaus Trust. Their job is to look at how to apply and make the Passivhaus work in the UK, with our differing weather patterns and culture. Jon gives an example of these different considerations being parts of Scotland, where people don’t want to open their windows for night-time cooling because of midges coming in, so different approaches have to be developed.

    The second aspect to their work is promote the adoption of the standard, by engaging with central government, local authorities and trying to get people on board.

    Jon accepts that while it’s a great standard it’s not perfect, so the third part of their work is carrying out research on specific aspects that can be changed and improved over time.

    There are different levels of Passivhaus standard

    There are two main standards: Passivhaus Classic for new build and EnerPHit for refurbishment. The criteria for achieving EnerPHit are slightly less stringent because it is that much trickier to do a retrofit. Certain aspects of the building are fixed and can’t be changed, so an allowance is made that if you can’t change those things you can still get Passivhaus.

    The Barrel Store – an EnerPHit Standard youth hostel. Image copyright Mac McClure

    In addition there are also two new standards: Passivhaus Plus and Passivhaus Premium, which are effectively the Passivhaus Classic but with renewables. Passivhaus Plus is where the energy generated by the renewables will exceed the energy demand of the house and reach zero carbon. So the energy generated will be equal to or more than your energy used during the year.

    Passivhaus Premium takes that a step further with enough renewables to create an energy positive house, so you’re generating more than you need and reclaiming money back from the grid.

    PHPP can be used to calculate embodied energy

    Within the planning tool they are now looking at add-ons which consider the embodied energy of the materials that you use and form part of the Passivhaus calculations. This will benefit people who are keen to use natural materials or who are just interested in understanding how much embodied energy there is. Jon stresses it is not a requirement for achieving the standard, it’s just developing the capacity to do it for those that would like it.

    Find out more

    Visit the Passivhaus Trust website, and learn more about their Passivhaus goes Personal campaign

    Transcript

    Download a transcript of the interview with Jon Bootland.

    Please connect with me

    Subscribe, rate and review the podcast in Apple Podcasts

    Rate and review the podcast on Stitcher

    Like our Facebook page

  • HPH278 : A beginner’s guide to self build – with Geoff Stow

    HPH278 : A beginner’s guide to self build – with Geoff Stow

    Having worked on his own hands-on group self build project, and site managed others, Geoff Stow shares his experience on where to start when it comes to self build.

    Interview with Geoff Stow

    Geoff’s involvement with self build started years ago when he worked with a community arts project in south London, making a video with a group of self builders who were promoting their scheme in Lewisham. So when Lewisham decided to do another scheme he put his name down, chairing and being part of a group of 13 that built their own houses on a Walter Segal project. From there, his involvement continued with working as a site manager for other group self build schemes, including the Hedgehog project in Brighton.

    “My background isn’t as a builder really but I think in some ways that’s quite interesting because it’s actually coming at it as a novice. I’m sympathetic with people who are trying to get a scheme off the ground.”

    Geoff also runs courses on timber frame self build, and self build project management at the Centre for Alternative Technology in Wales.

    Hope Wharf
    Hope Wharf

    It’s likely to be harder than you’re expecting!

    Geoff says he’s never met anyone who said they wished they hadn’t done it, but does stress that you should be prepared for a lot of hard work. He thinks there is actually very little in place to make things easier, with the majority of things at the beginning like planning and finding out how to connect services, being geared up to failing.

    Whereas most people spend their time at the beginning sketching designs for a plot they don’t yet have, he recommends instead taking that time to research and understand the issues involved. That could be around planning, environmental issues, insulation, ventilation etc.

    Take the opportunity to go to the exhibitions to grow your understanding and help you talk the same language as the experts, but bear in mind that a lot of it is sales focused.

    Understand the issues around claiming back the VAT, and get yourself organised with a good accounting system so you can keep track of staying within budget.

    Build your knowledge by checking out some of the self-build books around, like Mark Brinkley’s Homebuilder’s Bible. They’re worth reading for finding out about things like health and safety requirements, working out how you’re going to organise your project, whether you might be able to site manage it yourself, and understanding what the relevant issues around that might be.

    Use your suppliers by asking for detailed information, and if they can’t provide it then don’t use them. Geoff gives the example of a window supplier, where you should be providing wall designs and asking what’s the best way of fitting them.

    Have a sensible budget

    Keep in mind that things rarely come in under budget or ahead of schedule, so have a sensible budget that is based on real costings, not just how much you’d like to spend or how much other people have spent. Be wary of the figures that people quote when they say their house cost X amount per square metre, as you never quite know what has been included and what has been omitted.

    Budget high for all of the initial stages. Things like the foundations, services and access roads can have plenty of unknowns and it’s much easier to price up more accurately for the above ground works. Add on a good contingency once you get quotes in as this should free up money later on.

    In addition to budgeting for the overall cost of the build, if you’re using a self build mortgage you will need to consider your cash flow. They work by releasing money once a stage is finished, so although you might have enough money in total, you might find the project grinding to a halt if you do not have it available at the right times.

    Finding land will probably mean making compromises

    Geoff’s key piece of advice for finding land is to be flexible, as there’s not that much of it around. He thinks it best to spend time in the area where you’re looking as quite often word of mouth can be helpful.

    Take the time to understand your site

    Geoff estimates that, depending on your skill base and level of organisation, around a year is a good length of time to spend on your research. As part of this he recommends spending time on your site and understanding how to place the house so you can get the best out of it. This will include things like orientation, window placement and learning how the sun falls on the site at different times. During this period you can also be going to exhibitions and talks, doing courses, going on Passivhaus open days and speaking to other people that have built their own homes.

    Focus on getting the fabric of the building right

    Geoff says you’re never likely to hear someone say that they wish they’d put in cheaper windows or used less insulation! So concentrate on getting the insulation, windows, detailing of doors, heating systems etc right, and getting it to the best quality that you can afford. It doesn’t necessarily have to be the perfect house straight away, and you can always retrofit your dream kitchen or build a second stage later when finances allow.

    Speak to other people for advice

    Get as much information as you can from suppliers and manufacturers about their products and their detailing. Also speak to builders’ merchants who might be able to suggest alternative products that you might not have come across.

    Geoff follows a couple of Facebook groups which he says, if you filter through a lot of the rubbish and sales pitches, can actually have really good information and experience that people are willing to share.

    “There’s no right way of doing it…what there are is a lot of wrong ways!”

    Geoff stresses that there is no right build system to use, and the method that you choose will be based on a lot of criteria. Whatever method you do choose, just make sure that it’s of the highest quality you can afford.

    A lot of it will be down to personal preference, and whether you like timber, stone, brick etc.

    Geoff’s preference is for timber frame, partly for the accuracy and speed which it affords. He personally would also avoid very innovative systems by very small companies as there can be a question of whether or not they can actually deliver.

    Also consider what kind of products you want to be using. Some people might want high performance foam insulation, whereas others will want to go as natural as possible and use sheep’s wool or Warmcel type insulation.

    “Whatever building method you go with, you just need to really understand what the issues and the criteria are. The good points and the bad points. And ignore what people say about their method being the best, it’s modern or it’s developed by NASA or something ridiculous. Just understand what the issues are with all of them and base it on real costs.”

    Decide how much involvement you’re going to have

    As a client there are options as to how involved you will be on the project, ranging from paying huge sums of money to a building company who will do everything for you, to getting hands-on and doing practically everything yourself.

    Probably the biggest deciding factor is thinking about what skills you have, but not necessarily assuming that because you can do something yourself it will necessarily be quicker or cheaper.

    “So, if a job that a skilled person can do quickly and well and you can do fairly well and take a long time over, that might mean that it’s longer before you move in and you’ve got more mortgage repayments, more insurance, if you’re renting a house then there’s the rent that you’re paying while you’re doing it. So, you might think you’re saving some money but actually, are you really?”

    You might also find that by doing a job yourself and taking longer about it, you might be holding up the next trade that can’t come in and do their job until you’ve finished. Instead there might be jobs that you can do which won’t involve holding anyone else up, like prepping and putting up cladding for example.

    When it comes to managing the project, you have the choice of paying someone else to do it, or doing it yourself. Obviously doing it yourself in theory should save you money, if done well, but consider whether you have the expertise to: keep things on track and on budget, get prices and employ subcontractors, nudge people when needed, make sure the work is being done to a high standard, check health and safety standards are being adhered to, keep neighbours on side etc.

    Do it on the terms of what you can afford, what skills you have and what you want your level of involvement to be.

    Being too fixated can be a common pitfall

    Geoff sees people that might become completely fixated on building a straw house for example, when actually the site they have might not actually be ideally suited.

    “It’s just understanding the issues around those sorts of things and not necessarily getting very fixated on one thing where you end up making your build really complicated because you’ve got this one fixed idea that you saw somewhere on television that you want.”

    He also says that no matter what you do there will be people saying that you shouldn’t have done it that way. And maybe even you yourself will look back and think you might have done it differently, but just try to get as much right as you can based on the knowledge and research at the time.

    People always say they want to be in by Christmas!

    Geoff suggests when it comes to how long a project will take, that if you’re planning to do a lot of the work yourself then try and avoid it going over two winters, as the second is always particularly tough (especially so if you’re living in a caravan!) Realistically you could be looking at 12 to 18 months on site, but less than that if you have builders.

    He also recommends trying to get as much finished as possible before moving in, even if that means throwing money at some good contractors to speed things up. Finishing off works once you’re living there is much harder to do and becomes less likely to ever get done.

    To help keep on track with the budget and schedule, try not to make changes as you go along. You can make minor changes but you don’t want to be deciding to change window placement or move walls once work is on site.

    Work with an architect who is on your wavelength

    Keep a scrapbook of ideas and images that you like and can show to a designer or architect, and make sure you work with someone who is going to design the sort of thing you want.

    Although it’s not necessary to employ an architect, having a good one on board that is sympathetic to your ideas can elevate your plans and give you a wow factor, rather than simply being a series of rooms joined by a corridor.

    Having an architect involved could just be paying someone for a simple check over your plans and offering advice, to a full package of designing the house, getting it through planning and building control, and seeing the whole project through to completion and sign-off at the end.

    A key consideration in choosing who to work with is finding someone who is on your wavelength that you feel you can work with. Ask for proof that they really understand the issues that matter to you, as some might claim to be providing a sustainable and energy efficient building just because it complies with current building regulations.

    Participants on a timber frame course

    Find out more

    Visit the website of the Centre for Alternative Technology

    Join House Planning Help’s Facebook group

    Transcript

    Download a transcript of the interview with Geoff Stow.

    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

  • HPH267 : Self build tips, eco design and the climate emergency – with Kevin McCloud from Grand Designs

    HPH267 : Self build tips, eco design and the climate emergency – with Kevin McCloud from Grand Designs

    Kevin McCloud from Grand Designs shares practical advice on how to approach an ecological build, and comments on how architecture needs to change to address the climate emergency.

    Interview with Kevin McCloud

    Kevin McCloud has been synonymous with self build for the last 20 years. No doubt anyone planning their own project has had conversations with friends, family and colleagues about Grand Designs, as the programme has inspired a generation of people to dream about building their own home and, for some of those, to make it a reality. As well as being integral to the success of the TV show, Kevin is also the founder of HAB custom build houses.

    Grand Designs has diversified

    The busiest period of filming for Grand Designs is between May and October when Kevin can be filming up to fifteen hours a day, for three days a week. Because it’s impossible to know whether a project is going to take several months or several years they’re never quite sure what is going to end up in each series.

    Kevin attributes the show’s longevity to being able to find interesting stories that they haven’t covered before, whether that might be about a Passivhaus construction, a new technology or building for a disability.

    The Grand Designs brand has expanded to include ‘Grand Designs: House of the Year‘ in association with RIBA, and in 2019 also brought us ‘Grand Designs: The Street‘. This followed a number of self build projects taking place on a single street on the Graven Hill development in Bicester, with plans to return and film another series.

    Kevin says one of the most significant films he made was in series one, which was a community housing project in Brighton called The Hedgehog Housing Co-op, that used a Walter Segal construction method. In the future he would be keen to follow another community self build co-housing scheme, but says that they’re sadly very hard to find.

    There have been some stand-out eco projects

    Some of Kevin’s favourite projects have been ones with a focus on sustainability. One he particularly enjoyed was Ben Law, who in 2003 built his house out of his own coppiced wood. He describes it as being a beautiful story where nothing went wrong to create a fabulously beautiful house.

    “It was a film in which the word sustainability was mentioned once by Ben and I thought that was great. It elegantly told the story without hammering it on people’s heads.”

    Copyright ben-law.co.uk

    Another memorable one was the Lammas Project, which followed a couple building in Wales. He says it was a beautiful film about super low-impact living that was as much about the lifestyle as it was about the architecture.

    “It’s rather like ecological cars. They don’t exist. There’s no such thing as an ecological car. It doesn’t matter whether it’s full of batteries or it runs on dog poo. The point is, it’s all about our consumption and use of vehicles that determines whether their use has an impact on the planet. That’s where fundamentally the largest amount of environmental impact happens, in use.

    “And it’s the same with dwellings. So, you can build yourself an eco-house but if you continue to drive fifty miles to work every day and continue to live an exorbitant lifestyle, it doesn’t really achieve very much.”

    Being asthmatic himself, Kevin had a keen interest in Elinor Olisa’s healthy home that featured in the last series. With two children that suffered from life-threatening allergies, Elinor researched every product coming into the home to check for VOC levels and potential triggers. She has worked with the University of York to monitor the environmental performance and the results have been staggering.

    “A fabric first approach is glorious”

    A theme of the recent series and also in his own work, is a leaning towards a fabric first method of building, rather than bolting things on to make them seem more sustainable. Invariably the latter is an expensive and unnecessary way of working, but choosing the right materials and using them in an intelligent way is a far better approach.

    “It’s like the argument about the Americans and the Russians in their Space Race. The Americans spent tens of thousands of pounds developing a ballpoint pen that would write upside down in space, and the Russians used pencils. I don’t think that’s true but I just love the story.”

    A sense of responsibility

    Kevin believes the responsibility as architects and builders should be to build buildings which are super-efficient in terms of how they use energy and their resources, but they should also ‘deliver a quality of life that makes their arguments utterly compelling.’

    Achieving this takes a combination of good design where homes cost very little to run, where the experience of being in the buildings is uplifting and where people want to stay and build a community.

    “It’s the idea of how you use the spaces in between buildings to create social sustainability which has in itself a collective reduction in demand on the planet’s resources. In other words, if you share an allotment and you grow your own food; if you join a car club because you know your neighbours and you want to do it; if between you, you buy a bicycle for the street; or buy one trampoline for five households for the kids; or one shed; or one lawnmower between five homes; what you’re doing is actually, you’re sharing cost, you’re saving yourselves loads of money, and you’re also saving resources and making your collective imprint on the planet lighter.”

    People often think of self build as a collection of ideas at the start

    These ideas might be around what sort of bathrooms, kitchens, taps, sofas, lights etc that people like, and they assemble the home based on aspects which are more associated with the interior design than the architecture.

    Kevin sees architecture as being:

    “a process of design which is very good at resolving all kinds of issues to do with how buildings, places respond to where they are, to site, to the environment, to their location, to the passage of the sun, to how they function in engineering terms, but also how they provide uplifting and exciting spaces for their occupants that lift the spirits.”

    For him architecture is about creating a connection with the outdoors, while also problem solving things like storage space, and a lot less about the taps!

    Grand Designs ‘The Street’ (copyright gravenhill.co.uk)
    Grand Designs ‘The Street’ (copyright gravenhill.co.uk)

    Enable more people to self build, as it can be truly empowering

    Kevin says that it’s pretty much established that the middle classes can go out and build for themselves, and he would like those opportunities open to more people. He believes that through community you get a far greater sense of attachment to a place and an accompanying sense of empowerment from building your own home. It’s a combination that could be life-changing for many people.

    To do this, self build needs to be:

    • More widespread
    • Facilitated by local authorities
    • Have dedicated sites, with communities of self-builders working together
    • Truly affordable
    • Have more co-housing community schemes
    • Have housing associations working with groups of their residents as clients to build accommodation

    Kevin would like to see people being empowered in as many ways as possible, and yet the system in the UK is set up to favour the large developers controlling the market. While he wouldn’t suggest a future entirely dominated by self build or community self build, he would like to see a diversity of offerings which would create a healthier market.

    Large numbers of people wanting to build together within a community can put pressure on the authorities to deal with their land assets in a different way. There is even a question of whether land in public ownership should have a financial value attached to it, because of the net social capital that can be created by building together, and which is very evident in schemes across Europe. And if that community can be further enhanced with car share, improved cycle routes and better public transport and sharing generally, then that social capital has been increased even more.

    Development is a dysfunctional industry

    In considering what it would take to solve the housing crisis in the UK, Kevin says he would need to be the Prime Minister as the industry is so dysfunctional!

    “I would empower small and medium enterprises; I would mitigate against the large housebuilders; I would mandate every single local authority to allocate land. I’d use the Right to Build Act in fact.

    “The trouble is, everything I’m describing has already been tried. And that’s the difficulty. It’s not one problem. We have a crisis in numbers; we have a crisis of quality; we have a crisis in affordability; we have a crisis in planning. We have only half of the number of planners that we need. And we don’t have within central government a statement of faith. And what I would personally like to see, if I could do one thing, I would announce a national statement of faith in social housing.

    “We need to move back to a world where we integrate, where tenure is blind, where you can’t tell who owns and who rents, where housing is considered a basic human right, and we need to create the mechanisms to make that affordable not just to own but to rent, to share, and to occupy by whatever means. There are plenty of tenure models around the world which work.

    “So, what we have is a binary system in the UK which is hilariously out-of-date and a market delivery mechanism which is dysfunctional and broken. So, we’ve got lots to mend, lots to do, but by just saying, ‘we believe in council housing’ or ‘we believe in providing high quality housing for all and we will do everything we can to achieve that’ would be a wonderful thing.”

    Grand Designs Live

    The Grand Designs Live exhibitions take place in the UK twice a year. Kevin is proud that they offer tangible opportunities for people to touch and feel products and experience their quality. As part of the exhibition there is also an exchange of ideas where you can get help and advice from experts.

    Milk bottle house at Grand Designs Live

    With his passion for innovation, Kevin is excited by the new technology being showcased, with exhibitors now selling products on their stands that only a couple of years ago were in the ‘Green Heroes’ section.

    Find out more

    Catch up with previous episodes of Grand Designs

    Visit the websites of:

    Transcript

    Download a transcript of the interview with Kevin McCloud

    Please connect with me

    Subscribe, rate and review us on Apple Podcasts

    Like our Facebook page

    Follow Ben Adam-Smith on Bluesky

  • HPH191 : Key decisions that impact on the sustainability of a house build – with Lloyd Alter from TreeHugger

    HPH191 : Key decisions that impact on the sustainability of a house build – with Lloyd Alter from TreeHugger

    Lloyd Alter from TreeHugger shares his advice on what we should be prioritising as 21st century self-builders.

    Interview with Lloyd Alter

    We catch up again with Lloyd Alter, whose work as an architect and a real estate developer led to his interest in modern building methods. He blogs for the website TreeHugger and also teaches sustainable design at Ryerson University in Toronto, Canada. Previously, Lloyd’s talked to us about worldwide trends in green designs.

    Don’t measure value in pounds per square foot

    Lloyd says that size will be the most important decision about a house build because so much relates to it. While building small may be preferable for sustainability, he acknowledges there are various problems to overcome.

    Some contractors may refuse work on smaller houses, or argue that a bigger house is better value. Lloyd warns against buying more space than you need. A bigger house may cost less per square foot but that is a dangerous criterion for measuring value. He explains, “It will cost you more per unit of area to build smaller but the aggregate, it will still cost you less.” Operating and maintenance costs will also be less with a smaller dwelling.

    House size may be dictated by the plot

    Re-sale value can force a self-builder into a larger project. Often it’s the land that really has the value, so there’s a judgement to be made about the right sized house for the size of the plot. And Lloyd points out that putting in services costs the same regardless of house size, potentially making it harder to recoup costs on a smaller house.

    By-laws can, in some instances, prevent small homes being built. For example, Lloyd explains that some North American municipalities fix minimum square footages to guarantee a minimum tax return.

    Balance location with lifestyle

    Lloyd recognises the dilemma for self-builders who want to minimise their carbon footprint but can’t afford the expensive land located close to facilities.

    Low energy buildings can reduce environmental impact, and changing habits can also mitigate high-energy consumption. Someone Lloyd knows – who lives 9km away from town – cycles, uses a hybrid car when he has to drive, minimises shopping trips and avoids ordering things delivered by truck. Lloyd himself tries to balance his many air miles by cycling and keeping his house at “incredibly low temperatures”.

    An independent expert will help you design for sustainability

    In a poorly planned house, you pay more for a poor living experience. Lloyd mentions one self-builder who incorrectly fitted insulation and this decision threatened to destroy his house.

    For Lloyd, an architect should “help you get to the essentials and put the essentials together in the most efficient, satisfying and beautiful way.” He sees this as directly linked to building sustainably: “The key to sustainability is living with less and the key to living with less is to have it designed properly.”

    To choose an architect or builder, Lloyd suggests going to see their work and spending enough time with them to know that you like them, they understand you and that you can understand what they’re saying; clients shouldn’t have to deal with what he calls “Architectese”!

    Simplicity should be designed into the house in the first place

    So-called “smart homes” are fashionable but Lloyd is wary of unnecessary complexity that adds cost and needs maintenance. “My attitude is I like a dumb home!”, he says, citing the Passivhaus as a good example of this. Using less power means no need for a smart thermostat or a complicated solar panel system connected to the grid. “The house takes care of itself,” he says.

    Another reason to keep house design simple is to accommodate changing technology. Low voltage LED bulbs have practically eliminated the problem of lighting load and our technology increasingly runs on low voltage DC wiring. Lloyd envisages future houses solely using DC, so any high voltage electric systems fitted now should be kept accessible.

    As different building elements last different lengths of time, Lloyd’s advice is to prepare and keep things simple. “Put as little of it as you need in. Because at some point, you’re going to have to redo it anyway.” Homeowners should be able to access, change or fix any systems in the house:

    Element of your propertyHow long it may last
    LandForever
    Frame of your house500 years
    Cladding200 years
    Windows100 years
    Plumbing50 years
    Electrical20 years
    Mechanical systems10 years

    Fabric first is fairer as well as simpler

    Lloyd believes it is unreasonable to simply aim for “net zero carbon”, stating, “We have to use less, period. Even if we’re trying to offset it with energy from sun or wind.” Thus, investment in domestic energy production is another trend that Lloyd mistrusts. Compared to the huge amount of energy used for transport, he describes solar panels on roofs as inconsequential. “We should be going after the big things. And that’s efficiency, not solar panels on the roofs,” he says.

    He remarks that policies of domestic generation of electricity disproportionately favour people who have south-facing roofs. Someone without a roof or who can’t afford solar panels will pay more for their electricity, meaning the poor end up paying for the grid. A fairer system in Lloyd’s view would be for everyone to live in houses that are built to a higher standard and use less energy.

    Preferred methods of building continue to change

    Lloyd teaches a sustainable design course and the content can change every year. Ten years ago, he taught about spray foam that seals and insulates efficiently, but we know now this foam contains unhealthy flame-retardants and some don’t even work below three degrees Celsius. The current insulation trend is for low carbon cellulose, although Lloyd prefers rockwool.

    On the subject of new building techniques, Lloyd says, “I’ve become very conservative as I’ve gotten older.” He sees people who want the “latest new thing” demolishing existing houses on highly sought-after plots. This discourages building really good quality houses because “they don’t seem to be building them forever anymore”.

    Construction methods can be more suited to specific locations

    Building with “brick and block” gives thermal mass, holding heat in the day and releasing it at night. Lloyd says that this principle works well in the high Arizona desert, with hot days and cold nights. In less extreme climates such as the UK it is less effective, and making bricks, concrete and mortar releases a lot of carbon dioxide before construction even begins.

    Homes should be comfortable, safe, secure and resilient

    A self-build should bring comfort and happiness. Just because it’s environmentally friendly doesn’t mean you have to suffer!

    Considering our changing world, Lloyd advises self-builders to prepare for power outages, provide some storage for water and food, and build high enough and not in the middle of a flood plain. He adds that if you have to cycle to get milk, then make sure you can actually do it! “That’s what a home is supposed to be,” he says. “A place of security and comfort. That’s what we should all be striving for.”

    Find out more

    Visit the website of TreeHugger

    Follow Lloyd Alter on Twitter

     

    Transcript

    Download a transcript of the interview with Lloyd Alter

    Please connect with me

  • HPH172 : The impact of setting your energy target – with John Palmer from Enhabit

    HPH172 : The impact of setting your energy target – with John Palmer from Enhabit

    John Palmer from Enhabit explains what happens if you choose not to go all the way to Passivhaus standard, including how this impacts on cost, energy efficiency and comfort. He also outlines a best practice approach if you are going to build with Passivhaus principles.

    Interview with John Palmer

    John is the Managing Director of Enhabit, a company that helps to improve building performance, efficiency and comfort levels. John is a qualified Passivhaus consultant, SAP and BRE Assessor, systems engineer and experienced project manager. Prior to joining Enhabit, he ran his own low energy design consultancy.

    First understand the implications of Passivhaus for your project

    If you are trying to set an energy target, John’s advice is to start by reviewing your plans in line with Passivhaus standards. This will allow you to fully appreciate what it might take to achieve Passivhaus. Once the implications are understood, you may take the necessary steps or make a conscious decision to compromise and aim slightly lower.

    Invest in professional advice at the design stage

    John says that Passivhaus is not so much more complicated than a normal build, it just requires more thought at the beginning. One of the key thermal bridges to eliminate or mitigate is where the ground floor meets external walls, which will require careful detailing and potentially some specialist materials. Paying for some extra time with your architect or Passivhaus consultant is a worthwhile investment.

    When clients commission a design review with Enhabit, they are shown a Passivhaus model of their design and given graduated options to see what’s possible with their house and how close they can get to Passivhaus, with indicative costs for extra requirements.

    Focus on a fabric first approach, not eco technology

    John says it’s easy to get bamboozled by all the technology available. Ground source heat pumps, solar panels, boilers, etc. all have a design life of around 20-25 years and will need to be replaced. However the walls of your building will be there for 80-100 years, so the extra investment you put into them at the start will repay itself time and time again.

    Architectural aspirations may make Passivhaus harder to achieve

    John explains that in Passivhaus terms, the shape of your house is the ratio of your liveable area to outside heat loss area. So you may need to compromise on an ambitious design if you want to target Passivhaus.

    If your plans have already incorporated professional advice, and you intend to follow a very high-performing fabric first approach, it may be you just need to add in a MVHR (mechanical ventilation with heat recovery) system.

    Alternatively you may find you haven’t gone far enough with the fabric of the building and need to change the specification of insulation, glazing, etc. This is typical of retrofits, where John says it’s quite hard to achieve the levels required for Passivhaus with the existing fabric.

    Heating a Passivhaus costs a very small amount

    The annual space heating demand in a Passivhaus should be no more than 15 kilowatt hours per metre squared per year. John comments that this is a very specific number and you may decide this is unachievable.

    The key is to understand what number you can get down to, and what that means. For example, a target of 30 kWh will cost you twice as much to heat your property in any given year than it would have done if it were a Passivhaus. But heating a Passivhaus costs very little, so doubling very little isn’t that much and is likely to be better than other new build properties in the UK.

    Every design decision will impact on comfort levels

    Doubling your space heating demand to 30 kWh will impact on comfort but the nature of this impact will depend on why you haven’t achieved the Passivhaus target of 15 kWh. John gives a few examples:

    IssueImplicationsImpact On Comfort
    Insufficient insulation in wallsHeat loss from wallsFeeling cold off the walls
    Poor detailing where walls meet ground floorThermal bridgingIf bad, noticeable cold spots and possible condensation/mould
    Window specification isn’t triple/ high-quality double glazingCold will radiate off the glazingFeeling cold in rooms at certain times of year

    Thermal comfort is all about constant temperatures

    Many homes, especially Victorian buildings, tend to have rooms that are hot near the ceilings but cold at lower levels due to drafts and a lack of insulation below the ground floor. John explains that although the average air temperature in the room might be ok, having cold feet and a hot head will feel uncomfortable! Paying attention to thermal bridges and insulation will help to achieve what John calls good temperature stratification.

    Building regulations rely on people opening windows for required ventilation

    Although our awareness of temperature is quite good, it’s harder to detect poor air quality. We may notice smells and detect when rooms are a bit stuffy, but that’s about it.

    Humidity, VOCs (volatile organic compounds), odours and nitrogen oxide levels are all examples of pollutants within buildings. John advises we need about 30 cubic metres of fresh air per person per hour moving through a property to deal with pollutants, but this isn’t achievable with trickle vents and extractor fans unless you start opening windows.

    An MVHR system will deliver the required level of ventilation, but there are other mechanisms out there superior to extractor fans that will give extra ventilation but perhaps not cost as much.

    Insulation, glazing and ventilation will cost more, but not much more

    These three aspects are typically more expensive than a normal new build, as a Passivhaus requires:

    • More insulation – but you’ll only be paying more for materials (approx. 0.5% increase on overall cost); the labour costs are the same
    • Triple glazing, for thermal performance and to avoid condensation and mould – the gap is closing between triple and double glazing prices
    • An MVHR system – for an average sized house this may cost £9-10k for supply and installation

    Of these, the greatest return on investment will be insulation.

    Some builders are willing to learn

    Hiring the right people to build a Passivhaus is another factor to consider. Although it’s still relatively new to the UK, John has found that builders relish the challenge of doing something that requires more detail and thought; they appreciate the ability to measure how well they’ve done, and revel in achieving the standard. He adds, “You have big, hairy builders hugging each other on site when they get their final air test and they’ve got down to the right levels.”

    Five helpful tips from John

    1) Visit a Passivhaus or speak to someone who lives in one, to see what it can deliver from a living experience

    2) Find out what would be involved in achieving Passivhaus for your project

    3) Understand how each decision affects the final design, floor space, efficiency and comfort

    4) Put an MVHR system in, regardless of your airtightness target; ventilation and air quality are worth doing as standalone

    5) Have some form of quality control in place, even if you’re not targeting Passivhaus, to get the results you’re expecting

    Find out more

    Passivhaus Trust

     

    Transcript

    Download a transcript of the interview with John Palmer

    Please connect with us

    Subscribe, rate and review us on Apple Podcasts

    Like our Facebook page

    Follow Ben Adam-Smith on Bluesky

  • HPH119 : Sourcing materials for your self build – with Harvey Fremlin from the National Self Build & Renovation Centre

    HPH119 : Sourcing materials for your self build – with Harvey Fremlin from the National Self Build & Renovation Centre

    Harvey Fremlin, Managing Director of the National Self Build and Renovation Centre, explains how to go about sourcing sustainable materials for your self build.

    Harvey Fremlin

     

    Interview with Harvey Fremlin

    In 2008, after working on a construction site, Harvey joined the team at the National Self Build and Renovation Centre (NSBRC). The centre is a permanent venue for independent advice and support and has exhibits, workshops and courses for people with an interest in self-building or renovating.

    Centre Blue Sky

    Neil Helpdesk

     

    “Don’t be afraid to big-up your project!”

    It is likely that at some stage of your project you’ll be buying materials from a builders merchant. They can be intimidating places if you’re not in the trade.

    Harvey says that some merchants are more self-builder friendly, so it’s worth shopping around and not being afraid to talk about your budget and how much you’ll likely be spending with them. That way you may be offered bigger discounts.

     

    Manufacturers and suppliers are increasingly happy to deal with consumers directly

    Harvey has found that suppliers and manufacturers are increasingly sending people with technical backgrounds to their shows, rather than sales people. This is because visitors are keen to know more than just what a system is and how it works. Instead they are asking questions about technical specifications, the advantages of one system over another, how to get maximum performance from the system and whether it is absolutely right for their project.

    Trade Village

     

    Fabric first – products later

    The mantra at the centre is “fabric first” – invest in the envelope of the building to reduce the energy demand before considering “shiny technologies” and renewables.

    Harvey stresses there is still a place for renewables and that the centre is a big advocate of them, but without thinking about the fabric and the building materials from the early stages of the project, they will be pointless.

    TV3

    Self-builders have a much longer term view on building their home, in comparison to a volume house builder:

    “They’re not necessarily just looking at the immediate cost of using a particular system or a particular technology, they’re considering the payback periods and what the long term benefits are of investing the money up front in terms of choosing those potentially slightly more expensive materials. But in the long term lifespan of that home there should be huge savings there.”

     

    Keep on top of availability of supplies

    It is important to consider availability, because depending on the lead times of products you could end up impacting on your whole building programme if you’re waiting for something to arrive.

    As well as keeping on top of when things are going to be delivered, bear in mind the stage at which your build will be when the next batch of supplies are going to be delivered, and whether there will be sufficient access.

    Cash flow will partly determine how much you can buy up front, but do consider storage of items – some are going to be bulky and need to be kept dry.

    “So if you can actually arrange for the products to arrive almost in a just in time scenario, so a day or two before you actually need them, it takes away an awful lot of headaches.”

     

    Keep your site and supplies secure

    If you have a lot of products on site you will need to keep your site secure, with adequate fencing and probably an alarm system. Most people will purchase site insurance and this will stipulate the security arrangements that will need to be in place.

     

    Do plenty of research before selecting your products

    Ultimately your choice of product will come down to individual preference. Ensure however you do lots of research, talking to companies, reading brochures, and comparing one product with another.

    Once you know the style you like, check that it will be permitted within your planning consent.

    As well as choosing your product according to style, cost and performance, you will also need to consider availability and whether the products you want are actually going to be available when you need them.

     

    Use your own judgement when selecting products according to their green credentials

    Harvey suggests being honest and asking yourself what you really mean when you say that you want to be sustainable. Is it because you’re genuinely concerned about climate change, or is it being worried about energy consumption and rising energy bills? Being clear about this can help shape your decisions about how you proceed to build.

    Harvey says that any company will argue that the products it is supplying are “green” and “eco”. But while there are companies that only deal with sustainable products, it is really down to you to decide what you feel is right for you.

     

    You can claim the VAT back on a self build

    If you are doing a self build project in the UK you can claim the VAT back, but this can only be done once. For this reason most people would usually leave it until the very end and the owner has moved in. For some people it can be a way of freeing up cash earlier in the project if budgets are tight, however they will not be able to claim again for subsequent purchases. Harvey’s tip is to ensure you keep every receipt carefully filed away throughout the build.

    TV4

     

    NSBRC course tutors are experienced self-builders

    First time visitors to the centre generally arrive full of inspiration and at the early stages of a project. Often they will return a few months later with different mindsets, where they’re focusing on the building systems and the materials that they might use. The courses the centre provides are generally aimed at first time self-builders, to give them plenty of information, advice and confidence.

    LT1

     

    Find out more

    NSBRC Logo

     

     

    Visit the NSBRC website

    Follow NSBRC on Twitter

     

    Transcript

    Download a transcript of the interview with Harvey Fremlin.

     

    The Hub update

    Our latest module covers insulation and airtightness, also touching on the Passivhaus standard. We’re looking at how you achieve high quality installation and the factors that are going to make a difference.

    There’s also another video in the Long Barrow Passivhaus story. They have finished the foundations and are building up the basement with insulated concrete formwork.

    By being a Hub member you can also join our closed Facebook group and network with fellow self-builders.

     

    Please connect with me

  • HPH062 : Does a Passivhaus Need a Heating System? – with Alan Clarke

    HPH062 : Does a Passivhaus Need a Heating System? – with Alan Clarke

    Building services engineer Alan Clarke explains what factors should be considered when choosing a heating system for a low energy home.

    Alan Clarke

     

    Interview with Alan Clarke

    Alan Clarke has been involved in energy and buildings his whole career. He’s worked on a variety of projects, from schools to housing developments and individual self-builds.

     

    N.B. In this episode we are talking about heating systems relevant to the central European climate. In hotter climates you will be focused on cooling rather than heating!

     

    A Passivhaus is Likely to Have Fewer Radiators than a Traditionally-Built House

    When it comes to looking at heating systems for a Passivhaus there are a couple of key differences to consider.

    Compared to a traditionally-built house it is not necessary to heat every little corner (as the heat loss from each room is a lot less).

    There are also no cold surfaces. So, in a Passivhaus (where thermal bridges have been eliminated, etc.) it will not be necessary to put radiators under the windows.

     

    The Amount of Heat a Building Needs Comes Down to the Heat Loss!

    In simple terms, the heating requirement of a house will be determined by the heat loss of all the elements of the fabric and the ventilation.

    The total heat load will clearly be affected by the size of the building, but then it comes down to the insulation value of the wall, the windows, the ventilation system and so on.

     

    Even in a Passivhaus You Can’t Dispense Completely with Heating

    Working with Passivhaus specifications and including heat recovery ventilation very low levels of heat might be needed but there’s no expectation that we can do without heat completely.

     

    The Snag with Solar Gains and Internal Gains is How Variable They Are

    Alan gives an example of why it’s a good idea not to do away with a heating system.

    He says: “You could have a sunny day when it’s -5ºC and with the right house no heating is needed. It’s great. Then a week later it could be raining, it could be 3ºC, completely overcast and actually it would get a bit cold.”

     

    Good Temperature Control is Essential

    In a Passivhaus it’s no longer simply a case of it’s winter we need heat: some days you need a lot and some days you might not need any.

    So good temperature control based on the temperature inside the house is important.

    Generally, if you’re using gas heating you’re trying to throttle down a boiler which is really too big for the job. So controls that are able to lower the temperature that it runs at are a good option. They effectively reduce the power of the radiators by reducing the temperature at which they run, as well as increasing the boiler efficiency.

     

    Reducing Energy Demand is Always the First Step

    Alan does not advocate moving away from gas as a fuel in situations where there is already a connection to the gas main.

    The reason for this is that the emphasis of a Passivhaus building is always to think about energy first and reducing the energy demand. So to some extent it is less important where that energy comes from afterwards because one source of energy is often convertible to another. The key point is to use less.

     

    Find Out More

    Follow Alan Clarke on Twitter

     

    Transcript

    Download a transcript of the interview with Alan Clarke.

     

    Join the AECB

    For building professionals in the UK, the AECB is a fantastic organisation that shares knowledge and aims to promote sustainable construction.

    Their yearly conference is also an opportunity to be invigorated by like-minded individuals.

    They have just hosted their 2014 conference in Bristol but this video from 2013 sums up what people get out of it.


      Video produced by Regen Media

     

    Please Connect With Me