Insulation helps smooth out extremes in temperature between inside and outside and can help in both the winter and the summer months keeping the indoor climate within a healthy and comfortable temperature range with a minimum of added heating or cooling assistance. It needs to be applied to the whole building envelope to be properly effective, but if you are retrofitting the ceiling is the most important as heat rises. (42% of heat is lost through the ceiling, 24% through walls, 12% through closed windows, 12% through ventilation and 10% through the floor.)

Criteria for selecting insulation material include a good insulation value or R value (the range is R1.6 to R2.4 depending on what part of the country you are in and where you are putting the insulation); ease of installation; fire resistance; insect and fungal resistance; not damaged by moisture; and not causing corrosion to other materials, particularly metals. A healthy and environmentally friendly insulation material includes the additional criteria of having no irritating particles, and no or low toxicity additives, and preferably from natural source materials.

Commercially available healthier insulation products

There are now many commercially available insulation materials that, although not necessarily totally natural, are a much healthier alternative to glass and mineral fibre insulation.

Wool has always been regarded as a good insulator for clothing, and has been developed into wool batts or loose fill. Keeping the loft of wool is important for the insulation value, and as wool tends to felt down the product needs to be bonded with resin or thermally bonded with polyester to keep its loft. Wool can absorb and release moisture without affecting its insulation properties. The addition of borax makes it fire retardant. Wool is healthier for the installer and the occupant, and better for the environment in its production and eventual decay.

Cellulose Insulation is generally made from recycled macerated paper, blended with glue and blown into the spaces between timber framing. One needs to be careful about what paper is being used, coloured printing inks can contain toluene and benzene. The glue used should be a water-based, PVA type, and the fire retardant should be borax. Glue is not needed for ceiling insulation, but it may need to be covered with a layer of building paper or timber boarding to prevent the paper and dust from blowing around.

Polyester Insulation is available in batt form, and provides a good alternative to those allergic to wool. It has been known to cause some allergies as a pillow stuffing, but this has been put down to the fact that the pillow cover fabric is not fine enough to prevent the smallest fibres from escaping. Although a synthetic product (therefore it takes longer to biodegrade), it is non-toxic and in fact gives off less fumes when burning than wool.

Pumice is a naturally occurring lightweight volcanic rock that is found in many parts of the world, but resources are limited. It is a sponge-like material, porous glass froth formed by expansion of gases when molten lava cools rapidly after a volcanic eruption. Due to its toughness and durability it has been used as a lightweight aggregate in concrete for over two thousand years. It is an inert material and therefore has no reaction with any of the ingredients of concrete and steel. It can also be used as raw material for under slab insulation, but it is difficult to compact.

Wood Fibre Cement Boards are composed of wood-wool impregnated with cement in slab form. They are light-weight, durable and strong. The fibres are mineralised, a procedure which retains the mechanical properties of the wood but stops the process of biological deterioration, rendering the fibres completely inert and increasing their fire resistance. They are then coated in Portland cement, bound together under pressure in order to create a stable, resistant, compact and long-lasting material. The slabs are normally used for wall and ceiling acoustic linings but they can also be used as an under concrete slab insulation.

Alternative Insulation Ideas

Several natural materials are eminently suitable as insulation materials but are either in the strictly experimental category – that is there is no product acceptable to New Zealand building standards – or there are overseas products not available in New Zealand. So to use them requires research and persistence to get them accepted by your local council. They include clay coated straw, perlite or vermiculite, cellulose board, wood fibre boards, coconut fibre board, flax slabs and hemp. Also a layer of bottles set in sand can be used as an under slab insulation.

For more information check out the following websites: www.planetaryrenewal.org; Construction Resources; Natural Building Technologies; www.buildgreen.ndo.co.uk; Woodfibre Floor Boards; www.wohngesund.at/daemmen/kokos

If you are interested in more information on Ecological Building Materials, the Building Biology and Ecology Institute has an Eco Products and Services List available for $20, which lists building products and related services available around the country.

For more information please contact:
Wellington Office – P.O. Box 1364, Wellington, ph (04) 801 8180.
Auckland Office – 1-697 New North Road, Mt Albert, ph (09) 479 3161.
Website www.ecoprojects.co.nz
Email bbe@ecoprojects.co.nz

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

Bay Solar & Electrical Ltd. | PO Box 236, Takaka, Golden Bay

Global warming may be gathering pace, but forecasters predict a cold winter. So how do we warm ourselves without warming the planet?

It might not be enough in itself to halt climate change, but we can take some of the heat out of global warming through personal action. The clean, green solution is renewable technology. Here’s a bit of a guide.

Solar electric (PV)

Solar panels th