The Eco Timber Project | Aotearoa / New Zealand

The selection of the right paints and finishes for your house when you want it to be as healthy as possible is difficult, and must be made with care. Conventional paint is manufactured with technical and economic performance in mind, often at the expense of health and ecology. Natural paints are generally less robust than conventional ones, so you have to decide what performance do you require and how much are you prepared to maintain the level of finish. Choose your finish to suit the surface and your lifestyle.

The Building Biology and Ecology Institute has some basic guidelines with which you can assess the use of coatings and the products available as to their suitability for healthier and more sustainable building. They are:

1. Is it necessary to have a coating?
   Paint and surface treatments are primarily for protection of surfaces, but there are many materials that you can build your house from that do not need a protective coat. Make use of these, particularly on the outside where weathering means regular re-application of coatings. Inside the house, use coatings more for colour emphasis.
2. A surface treatment should not impede air and water permeability and the hygro-scopicity of a building material.
   The diffusion and moisture regulation properties of a building material are a vital part of maintaining a healthy indoor climate, your house should be able to breathe just as your clothes and skin does. Natural paints “breathe” readily, synthetic paints are more limited in that capacity.
3. A surface treatment should not create electrostatic charges.
   “Plastic” surfaces create electrostatic charges, which lead to a higher proportion of positive ions, which in turn affect the well-being of a building’s occupants. Natural paints do not create electro-static charges.
4. Use your sense of smell
   A paint or surface treatment should have a low or no odour, and smell pleasant. Remember that something that seems relatively unobtrusive on first sniff can be intolerable by the end of a day’s painting.
5. A coated surface should have a matt or low sheen finish
   A highly polished surface creates several problems: sound absorption is decreased and sound reflection increased; glare is produced; the possibility of skidding is increased; air and water permeability is decreased; and the hygro-scopicity of the material is decreased.
6. A surface treatment should either be durable or easily re-applied.
   Most people prefer low maintenance, but a simple re-application of a product such as an oil/wax finish without sanding and scraping gives an instant lift to a surface.
7. A paint or finish should preferably use naturally occurring and renewable ingredients.
   Natural ingredients are less harmful to people or the environment, but some of the healthier synthetic solvents make for a better product than natural solvents and are sometimes used in “natural” paints. This may be acceptable to many people, but make sure it is acceptable for you.
8. A paint or finish should not use solvents or binding agents that emit hazardous or unpleasant fumes.
   Most petrochemical solvents are hazardous, but natural solvents should also be treated with caution. It is best to use water-based paints, which have a much smaller percentage of solvent in them.
9. The process of manufacturing and using paints should not pollute the environment.
   Natural paint products use natural ingredients rather than creating them out of petrochemicals. They break down faster when washed out from brushes. All solvents contribute to air pollution, so use water-based paints where you can to reduce this problem.

There are several different natural paint systems available in New Zealand, if you wish to know more about these, as well as about other building materials, the Building Biology and Ecology Institute has an Eco Products and Services List, available for $20 email, $25 hardcopy.

Building Biology and Ecology Institute
PO Box 1364, Wellington,
(04) 801 8180, (0800) 223 272,
Website www.ecoprojects.co.nz
Email bbe@ecoprojects.co.nz