Low-impact building

“The individual’s desire to build something should not be deterred! Everyone should be able to build and thus be truly responsible for the four walls in which he lives. And one must take the risk into the bargain that such a fantastic structure might collapse later, and one should not and must not shrink from human sacrifice which this new mode of building demands. We must at last put a stop to having people move into their quarters like chickens and rabbits into their coops.” – Friedensreich Hundertwasser

What is low-impact building?

Apart from caves and very basic shelters, all human habitation damages nature to some extent. Low-impact building is about keeping this damage to a minimum. This introduction is about new builds (or extensions) – but remember that retrofitting an existing house is more environmentally-friendly than demolishing it to build an eco-home. Building your own home, either yourself or with a contractor, is a big project, and this is necessarily only a brief overview. There are lots more contacts and sources of information on this site that will help you with the details of low-impact building.

Materials

Building materials can be manufactured and delivered, or natural and local. Materials that don’t require factories to manufacture them, and don’t need to be transported large distances will have the lowest environmental impact. In a best-case scenario, materials will be natural and biodegradable, and found on-site or nearby. Natural low-impact building materials include timber, clay, lime, rammed earth, cob, straw, hemp and stone. Learn more about using these materials in their individual topic sections. Bricks, cement, metal, plastic and concrete all have a high environmental impact, but because they are familiar, easy and quick to use (and therefore profitable), they’re the most common building materials. It’s a different matter if those materials are reclaimed of course, as the energy and waste associated with manufacture is avoided. See Salvo for reclamation yards near you.

Size

Our homes have a footprint, i.e. they replace natural habitat, and are made from materials that have to be manufactured or harvested, and delivered. So from an ecological perspective, the smaller the better. An unnecessarily large home can’t really claim to be a low-impact building (although that claim is made all the time). See this letter from Oasis design.

Energy & water efficiency

A low-impact building won’t require much energy in its use. This can be achieved via passive solar gain, super-insulation, passive ventilation, no air conditioning and low-impact appliances. These things should be considered before energy generation via renewables. Passivhaus is an example of a European building standard based on airtightness, super-insulation and mechanical ventilation. Passivhaus buildings are designed to be heated passively by the sun, by electrical appliances and by body heat. Water use can also be minimised via water-saving devices, rainwater harvesting, greywater recycling, compost toilets and lifestyle change. The concept of eco-minimalism involves a restrained use of ‘bolt-on’ technologies and devices. With an appropriately-sized, well-designed, super-insulated house, plus energy- and water-saving measures and appliances, you won’t need so many extras. See here for more on eco-minimialism.

Location

If the occupants are not farmers, smallholders or forestry workers, a house doesn’t need more land than a conventional garden, and doesn’t really need to be in the open countryside. Productive land is limited, and if it’s turned into large areas of lawn or pony paddock, it’s a waste. A home for anyone other than land workers will have a much lower impact if it’s in a town, close to jobs, shops and mains utilities.

Lifestyle

In almost all cases, less environmental damage will be caused in the construction and use of a building than by the lifestyle of its occupants. You may have a ‘trophy’ eco-home, but its benefits will be wiped out if you’re a long-distance commuter, frequent flier or high consumer. And second homes are definitely not low-impact, no matter how you look at it. Homes have become better insulated and appliances more energy-efficient in recent years, but consumption has risen too. Of course low-impact homes are important, but we’d like to draw attention to lifestyle as well, as it’s often overlooked.

What are the benefits of low-impact building?

Environmental

This ultimately refers to the reduction of damage being done to ecology, on which we depend for survival. In the case of buildings, that comes down to emissions of CO2 and pollutants from the energy used in their construction and use, and toxification and habitat destruction via resource extraction, factories and transport infrastructure. The construction of buildings is responsible for around 10% of energy use and carbon emissions in the UK, but the use of those buildings is responsible for around 50% – the vast majority of which is heating. A low-impact building (using the criteria above) will reduce this damage, through choice of materials, and through design and construction methods that will minimise the heating required over its lifetime. A low-impact house can’t mitigate the damage caused by the lifestyle of its inhabitants however – that’s down to the individuals themselves.

Some building materials are carbon negative – the carbon locked up in a log cabin, for example, is about twice as much as the carbon saved by the electricity generated from a roof covered in photovoltaics for 25 years! (source: Green Building Bible) Let’s lock up carbon in our homes – by using locally-sourced timber or straw bales – or at least let’s use earth and stone where possible, rather than bricks and cement, which involve large-scale emissions of carbon and pollutants in their manufacture and delivery. Natural materials tend to be hygroscopic – i.e. they absorb and release water. This prevents moisture from becoming trapped in the building and causing rot and decay. They can also be repaired easily, meaning that natural homes can last for a very long time – often several centuries. But if it really is the end of the road for a natural home, it can (mostly) return to nature, causing no pollution in the process. But it’s also about the provenance of those materials. Local materials don’t require much fuel for transport, and it’s immediately clear whether their extraction is being carried out sustainably, neither of which is true of materials coming from further afield.

Health

Pollutants, both chemical and biological (e.g. moulds, bacteria, viruses, fungi and dust mites) have increased in UK homes since the 1970s, when lots of synthetic, non-breathable, non-hygroscopic materials began to be used for insulation, draughtproofing and damp-proofing. Now the UK has one of the highest levels of asthma in the world – almost 10% of the population – and rates in children have trebled since the 1950s. Humidity levels of 40-60% are optimal for human health, and can be maintained by natural, hygroscopic materials that absorb and release moisture naturally, without the need for mechanical air conditioning.

Lots of materials used in high-volume, high-impact construction are highly toxic to humans – formaldehyde in boards, arsenic in wood preservatives and VOCs (volatile organic compounds) in paints and finishes. Added to this is the huge range of toxins in furniture, cleaning products, bodycare products and clothes. All this has become more problematic with greater airtightness. Natural alternatives are available.

Cost

If you’re building a more-or-less conventional home but with, say, rammed earth or straw bale walls, there won’t be much difference in cost. The real savings come with self-build, and with local, natural materials that can be obtained for free or at very low cost (and as mentioned above, natural materials are hygroscopic, removing the need for and cost of mechanical ventilation). Simon Dale built a beautiful, unique home for £3k; Steve James built one for £4k, and there are many other examples – but pointing this out can result in your being labelled out of touch, or unrealistic. But it really can be done – it has been done – if you can get past the planning system and building regulations. Building regs and codes are written by the construction industry and the construction materials industry, who naturally enough, want to make money, supported by a government whose main aim is perpetual economic growth. No wonder they tell us that the really affordable, really low-impact building options are unrealistic.

Personal

Low-impact, natural homes are unique, fun to build and to live in, and there’s something very satisfying and just ‘right’ about living in a house you’ve built yourself. See the Hundertwasser quote at the top of the page.

What can I do?

This introduction is about self-build (including working with a contractor) rather than high-volume construction by large companies. However, conventional builders may not know much about low-impact building. See our directory, the AECB or the Green Register for listings of builders who will. If you have building experience, and you’d like to self-build, we also have listings of course providers in a range of natural building techniques. If you hire a builder, make sure that you obtain references, and see previous work that they’ve done – but also, learn as much as you can first, so that you retain control of your project. With an interesting natural build, you might be able to get volunteers to help.

Funding

You can build a super-eco home for very little money (see above), as long as it’s small, and you build it yourself, from local, natural materials that might be free. With a more conventional home, you’ll probably be looking for funding. As a rule of thumb, the land will probably be half the cost of building the house. When looking for funding, we suggest that you ‘go mutual’ – i.e. with a building society rather than a bank. Here’s why we think that’s important. Do a bit of research first, as not all building societies are mutual – many have been de-mutualised. The Ecology Building Society is a mutual with a good track record of funding low-impact builds. Talk to them about self-build mortgages, which are payable in stages, so that the builder has the finances covered, but with much less risk to the lender than if the money was all made available up front.

Location

In a remote rural location, a building can only be considered low-impact if you don’t bring utilities to it (at enormous environmental and monetary cost), but remain ‘off-grid’ in terms of electricity, heating, water and sewage. If you don’t want to be off-grid, and you don’t need to use the land, it’s more sustainable to choose an infill / urban plot where mains utilities are already available. There are various websites for finding building plots. Here’s one.

Materials

Decide whether you want to build conventionally but as ‘eco’ as possible, or whether you want to go completely natural. There’s a huge range of ‘green’ building materials to choose from, with different labelling systems, but generally, the closer to nature, the lower the embodied energy and toxicity. See Salvo for reclaimed materials. And for the natural approach, what’s available locally is good.

Avoid cement / concrete (even for foundations – there are alternatives, including car tyres with rammed earth, stone, flint & lime or brick/timber pillars); timber treated with toxic preservatives; uPVC; aluminium; and boards that contain formaldehyde. For finishes, you can choose natural paints and clay or lime plasters. Remember though, that natural materials will need a ‘good hat and boots’ – i.e. foundations that lift biodegradable materials well above the ground and a roof with a good overhang.

Remember that for new-builds, builders will be zero-rated for VAT, and you can reclaim VAT on most building materials – so keep your receipts. See here.

Design / planning the build

We’d say that simple is best when it comes to low-impact building. Take walls for example – there are plenty of examples of high-tech, multi-layered, complex wall systems, and yet natural materials may be more insulating (especially straw-bales), and will almost certainly be cheaper and more eco-friendly. Plus expensive technology may not be as eco-friendly as having energy-efficient appliances and more insulation. See ‘eco-minimalism’ (above). If you’re using an architect, make sure they know about sustainability – see AECB or the Green Register for listings. Talk to them about passive solar gain, thermal bridging, passive ventilation, airtightness, thermal mass, but research those things first so that you understand them. Architects can often be more inclined to the artistic than the practical. You also need to talk with a surveyor about the site and a structural engineer about the structural safety of your low-impact building design. There are other specialist areas to think about, from scaffolding to health and safety, and unless you’re an extremely skilled person, you’ll probably need professional help.

Utilities

You need to think about heat, power, water and sewage at the design stage of your low-impact building – they’re not add-ons. Your design can incorporate solar gain, energy saving and renewables – but common sense should prevail. Talk with people who’ve used your favourite technology, to make sure it’s going to work properly for you in your situation and in the way that you intend to use it – and that it won’t break down or need to much maintenance. Start with the un-sexy energy-saving measures like insulation and low-energy/low-water appliances and leave energy generation until last. See here for lots of ideas on utilities.

Planning / building regs / legislation

Find your site, get yourself a solicitor, talk to the local planning department, ask them about the local strategy around planning, especially as regards the environment and carbon-saving and where you can find key documents. Read them, because if you’re planning something that just doesn’t fit with the local strategy, you’re probably setting yourself up to fail. Building plots usually have outline planning permission, and if not, you can apply for it. The land has to be in the development zone, but we’d like to see reform to allow people to build super-eco homes outside the development zone, for farmers and/or smallholders at least. See here for more on getting planning permission, and here for how to get planning permission outside the development zone.

There is a range of voluntary and mandatory, government and non-government standards, codes, regulations, certificates, ratings, programmes and targets regarding sustainable buildings – different for each country, and constantly changing – so it’s not possible to go into details here; but talk to your architect / builder, and browse the BRE and AECB websites. AECB have their own standard, based on Passivhaus principles. In the UK, your self-build will have to comply with building regulations. Talk to your local authority building control officer, who will issue a completion certificate if your low-impact building is safe, structurally sound and energy-efficient.

You need a building control certificate if you want to get a mortgage, sell or insure your home. Some people of course have no intention of doing any of those things, and so just go ahead and build a cheap eco-home and face the authorities when they’re discovered. Tony Wrench chose this approach, and he and his partner are still living in the roundhouse they built in 1997. If you want to go that way, good luck – maybe bureaucracy will catch up with you, maybe it won’t. Of course, we don’t want to see the countryside fill up with illegal bricks & mortar commuter or holiday homes, which is why we’d like to see a different planning approach for low-impact homes for people who intend to work the land. Of course the legislaton / codes etc. have nothing to say about the building’s size or the occupiers’ lifestyles, which are usually much more environmentally-damaging than the building itself. And even if you’re living in an extremely low-impact way, in an extremely low-impact building, we’re still all living in a consumer society with a constantly growing economy, which will undo the benefits of your home and lifestyle. But it’s a start, and an example to others.

Maintenance

A low-impact building tends not to be maintenance-free – it might need slates or shingles replacing every now and then, a fresh coat of limewash or a repair job on a patch of lime or clay plaster. This isn’t a bad thing. Maintenance-free usually means that components have to be thrown away entirely when there’s not much wrong with them – and well-maintained timber windows (for example) can last much longer than uPVC windows.

Lifestyle

Then of course you need to equip your low-impact building and decide how you’re going to live in it – which includes furniture, appliances, floor coverings, curtains, lighting, cleaning products, bodycare etc. We have lots of ideas for you.

See our links page for lots more information and hand-holding when it comes to self-build and low-impact building. Good luck!

Thanks to Kim Siu for information.

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Whilst you’re here, why not take a look at the other 30+ shelter topics available? And don’t forget to visit our main topics page to explore over 200 aspects of low-impact living and our homepage to learn more about why we do what we do.

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The specialist(s) below will respond to queries on this topic. Please comment in the box at the bottom of the page.

Adrian Leaman of Wholewoods helped Ben Law to build his Woodland House in 2002, and since then has been roundwood timber framing, particularly reciprocal roof roundhouse building, and sharing woodland and woodcraft skills with people from all walks of life. He is a Forest School Leader and works with adults and teenagers on educational projects.