The RIC Good Wood Guide


- from the RIC Good Wood Project

Contents at a Glance...

Non Toxic Timber Treatments

Non-toxic Mud Brick Treatments

About Natural Timber Treatments

Why Timber Must Breathe

Non Toxic Timber Treatments

The ultimate non-toxic timber treatment is not to use any! Make sure circumstances require that the timber be treated to preserve it. If the timber needs treatment, use plant or earth-derived low-gloss, noise-absorbent materials, which harbour no unpleasant smells, which allow the timber to breathe (apart from waxes, say) and which do not allow the buildup of static electric charges in dry weather (such as with hard finishes like epoxy and polyurethane). Use non-skid surfaces on floors.

Note: For suppliers and/or manufacturers of all the products listed below, see Non Toxic Paints, Treatments, Finishes, in the Directory

Adhesives, Glues

Made by Bio Products and Livos Paints.

Borax for Borers and Timber Preserving

Timber which is liable to borer and fungal attack is most often found in internal components. Therefore, it is possible to treat it with an preservative, such as a solution of borax (sodium tetraborate) which would otherwise leach out if exposed to the weather. Borax is relatively inexpensive, and can be purchased at most hardware stores or chemists. It has cleaning, disinfecting, bleaching, deodorising insecticidal and fungicidal properties.

Boron compounds, which belong to the same group as borax, are commonly employed as fungicides and insecticides. Prouduced in the form of water-soluble rods and pellets, boron is inserted into drilled holes to stop wet rot. It is suitable for window frames and exterior woodwork. The London Hazards Centre in the UK considers it one of the few acceptable chemical timber treatments (although don't let children or animals swallow it).

(NB: It is not advisable to burn borax-treated timber in stoves or fireplaces, etc. Although not toxic, the boron compounds will damage fire grates.)

Cement Paint

Made by Porters Paints and Muro Paints.

Chalk Paint

Made by Porters Paints.


Porters Original Limewash is the trade name for a 'whitewash' made of rock lime combined with oxide-based pigments.

Milk Paint

Milk Paint is a generic and trade name for a non-toxic paint which contains a combination of milk and natural pigments. Made by Porters Paints.

Oil-based Treatments

Made by Bio and Livos paints, Organoil and OS Colour. (The distributors of Organoil in Australia claim that their product is a suitable secondary treatment for treated pine. Apparently it works as additional protection against weathering, and as well will assist in the retention of the very potent CCA treatment in the timber (where it should stay). This may also apply for other brands.

(NB: The more pressing problem with CCA is its end-of-life disposal, over and above its leaching from the timber during its working life. Manufacturers tend to play down this problem.)

Paint and Varnish Stripper

Woodfinishers' Pride is a non-toxic and biodegradable paint and varnish stripper, for use with recycled timber or wood products.


Made by Bio Products and Organoil.

Potash Paint

This is made by combining equal parts of 'potash water'1 (a mixture of sodium or potassium silicate and water) and borax and applying it in a 10 percent solution. This coating is fire, fungus and insect resistant.

Pyrethrum for Borers

The sapwoods of many species are susceptible to borer infestation. Pyrethrum is recommended for use on round poles, for example - a popular choice in low-cost home-building. Where they will be exposed, timbers will require painting to prevent leaching of the pyrethrum.

Sodium Carbonate

Bi-annual applications of a solution of sodium carbonate are effective in preventing certain kinds of fungal and insect attack, and stops the timber greying. (See also Wood Ash)

Timber Preservatives

Non-toxic, oil-based, paintable preservative treatments are made by Grimes Paints and Bio Products (wax-based treatments apparently can lead to delamination).

Timber temporarily exposed to the weather during construction can be coated with non-toxic preservative and protected until building is complete. Preservative can be applied and overcoated with paint or stain, etc, for timber that will remain exposed.

Tung Oil

Made by Intergrain Timber Finishes, Wattyl, Estapol, etc.

Tung, or Kekune oil has been used as the drying ingredient in varnishes for many years. In its own right, the oil when applied allows timber to breathe, and reveals the characteristics of the grain. Tung oil is derived from the seeds of the T'ung Tree (Aleurites spp), which is native to East Asia and the Pacific. (Japanese, Taiwanese and Chinese woodcrafters call it the Wood Oil tree.) It is also cultivated in the US and Europe.

There is still some debate about the toxic effect of tung oil on people, so if you decide to use it, choose one with a szero or low concentration of synthetic driers and additives.

Varnishes, Lacquers, Sealers

Made by Livos Paints, Organoil, Bio Products Grimes Paints - who also make shellac, and Auro Paints (US) and Safecoat (US).

Vegetable-based Paints

Vegetable-based paint products are sold by Livos Paints Bio Products and Auro Paints (US) and Safecoat (US), etc. Plant-based paints are still a bit harder to find than conventional paints, and are 25% more expensive. However on the plus side, apart from their environmental friendliness, they will not lift or peel from new surfaces and have superior coverage ability, usually requiring only two coats. (This is because plant-based paints are made up of 70-80% solids, while synthetic paints are only 30-50 %). Plant-based paints take about 2 hours to dry; water-based paints (which contain solvents) take about 20 minutes, and oil-based paints take about 4 hours.


Made by Porters Paints.


Made by Bio Products, Organoil, Mother of Pearl, and Grimes Paints. Eco Wood Finish (US) is made from beeswax harvested from the rainforests in Zambia, Africa by indigenous forest dwellers. Auro Paints (US) and OS Colour (US) also make waxes.

Wood Ash

A solution made from twice-boiled then fermented wood ash creates a weather-resistant finish when applied to timber. The solution may be coloured by adding particular kinds of bark during the cooking process.

Wood Stains

Made by Grimes Paints, Organoil, Bio Products and Auro Paints (US) and Safecoat (US).

For suppliers and/or manufacturers of all the above products, see Non Toxic Paints, Treatments, Finishes, in the Directory

Non-toxic Mud Brick Treatments

Note: For suppliers and/or manufacturers of all the products listed below, see Non Toxic Paints, Treatments, Finishes, in the Directory

Chalk Paint

For interior walls. Add cellulose-based glue and pigments to chalk saturated with water and apply. Mould resistant, but not water-resistant.

Clay Paint

Clay which has been 'washed' to retain the larger particles and then dried, is combined with fat or fish oil to make a surface finish suitable for interior and exterior applications and humid climates.

Dust Proofing

Grimes make a range of clear dust-proofers for mudbrick.

Earth Bonding Emulsion

Earth Bonding Emulsion is a (breathing) surface binder and protectant manufactured by Tech Dry of Melbourne.

Mudbrick Paint

Grime's make Mudbrick Colourcoats which are non-toxic and provide all-weather protection. (See also Cement Paint, above.)

Water Repellent

WRC Mud Brick Water Repellent is a treatment which both waterproofs and protects finished surfaces. WRC is water-based and non-toxic. Grimes Paints make silicone and oil-based water repellents.


This is a safe but bactericidal treatment in which a fermented 'sludge' of whitewash1 is made by carefully combining water and quicklime (which is caustic!) and setting the creamy mixture aside for a year or so. Pigments can then be added to match a colour scheme. Binders such as linseed, skim milk, casein (white cheese), or a mix of tallow, wax and resin may improve durability for external applications.

White Cement Paint

White cement is the stuff used to grout tiles. Combine equal amounts of this and calcium hydroxide to make a weather-proof finish which breathes.

About Natural Timber Treatments

by Chris Rew - architect, permaculture designer

The natural beauty of timber, its organic individuality and wholesome quality, makes it a popular material for those wishing to create a healthy, pleasing home environment. However, its naturalness also makes it vulnerable to insect and fungal attack. As world timber resources dwindle (and demand rises alarmingly), it is becoming increasingly important to protect wooden products against such attack, as well as excessive weathering and physical wear, which would prematurely recycle them back to the earth.

The Toxic 'Norm'

Unfortunately, most of the timber and wood products on the market are neither natural nor healthy. Most timber is therefore coated with paints, stains, varnishes or other mixtures containing poisonous chemicals. There is increasing concern about the effects on health caused by long-term, low-level exposure to such 'house-bound' chemicals.

Many chemically-based paints and varnishes use solvents or aromatic hydrocarbons such as toluene, xylene, benzene or ketones, esters and glycol-ethers. These substances are linked with brain, liver and kidney damage 2. Wood preservatives generally contain highly poisonous substances such as PCP and its derivatives, organic compounds such as TBTO and chlorinated carbon compounds such as Chlordane, Dieldrin, Dioxin, Lindane, PCB, as well as phenyl mercuric acetate and copper napthalenate. These can affect the nervous system and break down the immune system. Lead and cadmium, both highly toxic, may be used for pigments. Some monomers used to form synthetic resins such as acrylonitrile (Acrylic) and vinyl chloride (PVC) are also very toxic. Many of these substances are readily absorbed through the skin. Most are not bio-degradable, although some may break down into even more hazardous compounds.

The not-so Alternatives

There are organically-based products which offer an alternative to such chemicals, many of which are produced in West Germany. In Australia, there are no manufacturers of these products. However, companies such as Livos Paints, Organoil, Grimes Paints, Porters Paints and Bio Products market a range of paints, varnishes, lacquers, stains, polishes and wood preservatives made from natural raw materials. These ingredients include earth pigments, herbal fungicides, natural oils, waxes, resins and balsams. The products are made using recipes often dating back hundreds of years. By using appropriate, modern manufacturing methods, a high level of quality-control is possible although using typically variable natural ingredients.

Timber which Breathes

Unlike synthetic chemical paints and varnishes, these products do not always seal the surface of the timber. They prevent moisture penetration, yet allow it to breathe naturally. Heavy metals, dangerous pesticides and solvents are avoided.

The natural organic qualities of such products complement the natural beauty of timber. It is possible to effectively protect such a high value material without compromising our health or our environment.

Why Timber Must Breathe

- from 'Ecological Building and Living' 3

As an organic, cellulose-based material, timber needs 'vapour-exchange' with the atmosphere 4. Sealing timber by means of covering it with a plastic film, such as with synthetic paints or varnishes, means that the wood 'suffocates' and will lead to breakdown of its cellulose structure. Any other moisture-trapping material, such as plastic sheet and aluminium foil, etc, which are used in wall cavities, may have the same effect.

Trapped moisture in timber also creates the perfect breeding conditions for insects, as well as living conditions for fungi - the wood providing a cellulose food source for their sustenance. Mineral salt-treated timber with high moisture content that has been coated with synthetic, non-porous paint will tend to have salt blooms on the surface, leading to the paint peeling off its surface, and the eventual breakdown of the wood underneath.

Admittedly, ideal environment conditions for timber preservation are not present everywhere, so more often than not, the cell structure has to be protected. But this is best done by using the old, natural techniques. Plant oil, such as linseed oil, is ideal for the impregnation of wood. The molecules are ten times smaller than the smallest passage in the cell structure of wood, allowing it to fully penetrate and permeate. In earlier centuries, linseed oil was used to render masts of ships to make them sufficiently flexible and durable to remain seaworthy for long ocean voyages. There are timber houses older than 600 years in middle Europe which are still structurally sound, their timbers having been periodically impregnated with non-toxic mineral salts, wood tar or plant oils.

Today's plant chemistry paints still use naturally occurring ingredients, but with the advantage of more advanced techniques used in their manufacture. Thus, use of plant materials whose molecular structures allow vapour-exchange and therefore prevent mould growth or creation of habitat for breeding insects remains the best way for enhancing the appearance and protecting the function and durability of timber the ecologically sound way.

1.Red Gum or Angophora, which early European settlers found in abundance around the colony of Port Jackson, became known as the apple-tree and when burnt was high in potash, which improved the quality of whitewash and clay mortar when mixed with them.

2. See the Painters Hazard Handbook, in Books, Paint. See also some of the general titles in Books, Chemicals.

3. Pamphlet published by the proprietor a company of the same name, which supplied ethical building materials, supplies and information. The Guide has not been able to find current contact info for Ecological Building & Living (last known to be in Blackheath, NSW), and presumes they are no longer trading.

4. IE, to be able to regulate its moisture content in order to maintain its integrity. (The only exception would be if conditions existed to allow the timber to remain at a moisture level below 7 percent, such as could happen in one of the arid regions of the country).

For suppliers and/or manufacturers of all the products listed , see Non Toxic Paints, Treatments, Finishes, in the Directory

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