Facts about wood

Wood is a natural material made of cells and fibres. When first harvested, the timber is full of sap (moisture). Timber which is ready for use in the building industry, has had most of the internal moisture removed by various processes.

As timber ages, if it has no further protection, there will be movement of moisture into and out of the timber. This happens because of -

  • the obvious effects of the rain
  • the drying effects of wind
  • the heating and drying effects of the sun.

In addition, as the temperature changes at the surface, as it naturally does between day and night, the moisture moves into the cells (causing them to swell), and out of the cells, (causing them to shrink). 

This causes forces within the timber, which can result in:

  • warping
  • twisting
  • cupping
  • splitting

The ultra-violet effects of the sun cause changes at the surface of the timber, resulting in silvering. In addition, as timber is a natural material, it is attractive to: 

  • mould
  • bacteria
  • fungi

These cause unsightly stains, and eventually lead to rotting and decay.

How should I protect my timber

Obviously, timber must be protected from these effects if it is to last and look good. The approaches that are available are:

  • Paints (film forming)
  • Stains (film forming)
  • Natural Oils (barrier formers)
  • CD50 (non film forming - deep penetrating)

How do film formers work?

Most paints and stains work the same way. They provide a film or coating over the surface of the timber to stop the movement of moisture into and out of the wood. Some of these films claim to be resistant to UV light and will not break down in sunlight.

What can go wrong with film formers?

Placing a film or coating over the surface will work only until that film is broken. When moisture gets in behind the film, it may start to flake or peel off. When moisture gets into the timber it leads to warping and cupping etc., as detailed above.

Most film forming products rely entirely on the film to protect the timber. In addition, film forming products often hide the character of the timber. The visual effect of the timber grain and natural beauty is hidden under a coating.

Examples of broken down film formers

Broken down film former on garage door.JPG

What about oil - is it good for timber? 

Oils have been used for years to protect timber. Nearly all work by cross-linking close to the surface to provide a barrier which is similar in its effect to the film forming products. Some oils provide nutrients that support the growth of fungi, mould and bacteria. Fungi, mould and bacteria thriving within the oil can lead to unsightly stains, rot and decay.

What sets CD50 apart from other products?

CD50 is totally unique and different from other products. Most importantly, it is not a film forming product. CD50  is an oil based product that:

  • Contains Copper Quinolinolate (Copper 8) - an extremely safe preservative which is extremely, effective on bacteria, mould and fungi.
  • CD50's unique formulation allows it to penetrate deep into the timber where it works from within

How does CD50 protect my timber?

  • CD50 penetrates deep within the timber structure, coats the fibres and prevents the moisture movement into and out of the cells.
  • This controls warping, cupping, and splitting. In other words, the structure and shape of the timber is protected. CD50 gives stability to the timber.
  • In some cases CD50 can return cupped and warped timber back to near its original shape. With sufficient applications of CD50 cupped and warped weatherboards can be renailed straight again.
  • CD50 gives protection against termites and borer
  • CD50 controls mould, fungus and bacterial growth within the timber, giving protection against rot and decay.
  • CD50 does not break down in the UV rays of sunlight. This is particularly important in countries that have extremely high UV conditions, like New Zealand.
  • There is no "film" to break down, by sunlight, weather or mechanical effects.
  • Copper 8 is recognised worldwide for its effectiveness, yet when applied to timber, has little or no toxicity to humans and mammals. It is even suitable for timber that has incidental contact with food or potable rain water. As a liquid, CD50 is rated as a non-hazardous product. It is safe for humans, mammals, and for the environment.

Cracked, split and warped

The top board has been treated with CD50. The bottom board has had nothing. Both boards were left exposed to the elements together for the same amount of time.

CD50 will not crack, peel or flake and will assist the control of warping, cupping, and splitting, thus enhancing the service life of the timber.

Weather conditions affect timber

Weather conditions affect timber. The following illustrations show the difference that CD50 can make.


This is what happens to timber without protection.


This is how the timber is protected when CD50 is applied.