‘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 it?
Apart from caves, 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.
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 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 are 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 low-impact (although that claim is made all the time).
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 air tightness, 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 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?
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, draught proofing 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, body-care products and clothes. All this has become more problematic with greater air tightness. 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 for the government, affordable housing starts at £65k. If we point out that you could build 20 super-eco homes for that amount, we are labelled hippies, out of touch, unrealistic. But people, it can be done – it really can. 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 economic growth. No wonder they tell us that the really affordable, really low-impact options are unrealistic. See here for more information on costs and how to reduce them.
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. You can start by posting something on our forum.
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. Again, the Ecology Building Society has a good record with self-build mortgages.