In his 2008 book In Defence of Food, Michael Pollan set out his “Eater’s Manifesto”. It included: “Don’t eat anything your great grandmother wouldn't recognise as food” and “Avoid food products containing ingredients that are a) unfamiliar, b) unpronounceable, c) more than five in number”. We could apply the same rules to the materials we use in our homes.
While interest in healthy food has grown, we still live in homes built from materials that our great-grandparents would be hard-pressed to recognise and containing ingredients most of us could barely pronounce. Now, a handful of architects, designers and companies are questioning the impact of these materials on our health.
Three years ago, David Gale, director of Gale & Snowden Architects in Devon, co-founded the non-profit Building Biology Association — the UK affiliate of the Institute of Building Biology and Sustainability, founded in Germany in 1983. “At the heart of Building Biology,” he says, “lies the notion that nature is the golden principle that we should be designing our buildings to so that, for instance, air and water quality and electromagnetic radiation levels should match nature as closely as possible.”
Gale argues that as homes become more energy efficient, they can also become less healthy. “If you make a building more airtight, badly ventilated and have lots of toxic chemicals in it, you’re going to have problems.”
The research backs him up. A 2014 study by the University of Exeter Medical School found that the greener a home, the less healthy it could be. It concluded that “a unit increase in household Standard Assessment Procedure rating” — the measure of a home’s energy efficiency on a scale of zero to 100 — “was associated with a 2 per cent increased risk of current asthma, with the greatest risk in homes with SAP greater than 71”. New homes in the UK have an average rating of almost 80.
“We’re designing homes and schools where there are no windows that open,” says Amena Warner, head of clinical services for the charity Allergy UK. In a well-sealed environment, temperatures and humidity can rise to create the ideal environment for allergens such as the house dust mite and mould. As a result, Warner says occupants “might get allergic rhinitis — a blocked or runny nose — and they can also get asthma. We know that for the majority of children with asthma it’s driven by allergy.”
According to the housing charity Shelter, England needs to build at least 250,000 new homes each year. Yet could the rush to build be storing up health problems for the future? On the rental side of the market, more than 20 per cent of UK households now rent privately and landlords are incentivised to redecorate cheaply and fill their flats quickly. Many tenants experience what could be called “Queen syndrome”: everywhere smells of fresh paint.
Today, the average can of paint has an ingredient list as long as your arm — much of it toxic or carcinogenic
Paint is one of the biggest culprits in an unhealthy home. Walls, ceilings and woodwork are covered with the stuff and home-makeover television shows have normalised the idea of redecorating a room or two over a DIY weekend. Yet, colour aside, how many of us give much thought to what we’re splashing on to our walls (and our skin)?
Paint requires just three ingredients: a pigment (the colour), a solvent (the bit that makes it a liquid), and a binder (which sticks the pigment to the wall). How paint is made has changed little in the past century; what has changed is the source of its components. “We have switched from naturally occurring ingredients to derivatives of the petrochemical industry,” says Edward Bulmer, an architectural historian and interior designer who sells his own brand of environmentally friendly paint.
Bulmer’s Damascene moment came in the early 2000s when he was commissioned to decorate a new part of Goodwood House, an estate in southern England. “I was asked to be very careful about what I used in my work and judge them by two criteria: their environmental impact and their toxicity,” he says. “I was proposing stone and plaster and furniture made from wood, horsehair and leather and curtains of wool. And then I met the paint and thought ‘what is it?’ If you turn a tin of paint round, you can’t tell anything about what’s in it, and if you don’t know the ingredients of something, you can’t judge it.”
Calls to major paint companies drew a blank; their technical departments were unable — or unwilling — to offer a list of ingredients. Instead, they sent data safety sheets. “They are a matter of compliance,” says Bulmer, “but they only tell you about a small minority of the worst ingredients. They don’t tell you about the main bulk of the paint.” So he decided to make his own.
Today, the average can of paint has an ingredient list as long as your arm — much of it toxic or carcinogenic. And given that up to 60 per cent of what goes on the wall then evaporates, if you don’t ventilate your home or allow the paint to off-gas — that is, to allow toxic gases to be dispelled — for long enough you are inhaling a large proportion of that.
Of course paint is not the only building material that can have a health impact. MDF — medium density fibreboard — is a favoured material among builders and carpenters looking to produce cupboards and shelving, and to box in pipes or baths. It can give a very smooth finish and is cheap and easy to work with. The downside is that it is made from extremely fine wood dust held together by copious amounts of glue, which contains formaldehyde.
“It’s the asbestos of tomorrow,” says Gale. “We knew back in the early 1900s that asbestos was dangerous but it wasn’t banned until 1999.” Formaldehyde can also be found in the backing of linoleum flooring, the glue in plywood and other composite materials.
Ventilation is key. The average family of four produces 16 litres of moisture per week
Heating systems, too, can cause health issues. Small, hot radiators not only trap dust in and behind them, but create convection currents that disperse that dust around the room. Underfloor heating is an improvement as the lower temperature warms a room more evenly. Yet some heat is wasted (under sofas etc) and it still creates convection currents. Gale suggests a similar radiant system of pipes that can be fitted into a wall and plastered over, more evenly warming a room without the strong convection currents that disperse dust.
So what can be done? Ventilation is key. The average family of four produces 16 litres of moisture per week. The optimum relative humidity level is 50 to 55 per cent and to combat damp problems in poorly ventilated homes, dehumidifiers such as Meaco’s Low Energy 20L can help regulate levels.
As the UK government is committed to an 80 per cent reduction in carbon emissions by 2050, and new homes must have increased air-tightness to help meet this target, a longer term solution would be to ensure that all new-builds are fitted with more comprehensive ventilation systems.
The gold standard for Passivhaus and energy efficient buildings is Mechanical Ventilation with Heat Recovery. An MVHR system brings in fresh air from outside, using the heat from the stale outgoing air to warm it.
The pursuit of healthier building materials is starting to catch the attention of larger organisations too. Google linked up with the Healthy Building Network in the US last year to work on Portico, an online database of materials that lists all ingredients and rates how healthy they are. The aim is to enable designers, architects and developers to make informed decisions about the buildings that many of us will end up living and working in.
Yet for homeowners looking to redecorate, Gale has his own basic manifesto. “As a general rule,” he says, “the more natural the better.”
Photograph: Bridgeman Images