- WPC-Decking vs. Natural Decking
- Best Decking Timber Species
- Timber Decking Treatment
What are the types of timber decking finishes?
And the advantage of decking oils?
The reasons for applying a timber finish at all are:
Firstly, wood finishes are water-repellent and that enables the control of the moisture content.
By absorbing and releasing of moisture, wood expands and shrinks.
This process can cause deformation if the drying happens too quick (the boards can warp or even crack).
Secondly, pigment enriched timber coatings protect timber from uv-light (ultraviolet light) to a certain degree.
Is wood exposed to ultraviolet radiation (sun light) over a long period, a tenth of a millimetre of the surface will get damaged
(in particular the lignin will become denatured).
The cellulose gets pulverised and the colour of the surface turns into a silvery-white to dark gray.
Not a big deal for the timber itself but a film building finish will lose its adhesion and peel off.
And thirdly, timber finishes are used to simply enhance the look and colour of timber.
It is important to consider the different advantages of the finish types before application as it may be very difficult to change from one type of wood finish to another one. For example you would have to remove the paint completely if you used a film building sealant the first time and now want to apply decking oil.
Let’s concentrate on the different types of timber finishes and their advantages.
- Decking oils (recommended) penetrate a few millimetres into the wood fibre and support the natural weather resistance of timber. Decking oils preserve the natural texture of wood most and change the natural appearance least. Basically all commercially sold decking oils contain colour pigments to protect from uv-light. Light colours are often called ‘clear’ or ‘natural’ but they are not 100% translucent. Decking oils do not seal off the timber pores, act water-repellent but still allow minimal absorbing and releasing of moisture. The surface film of decking oils is insignificant, so it cannot peel or become slippery when wet. Oils are the easiest to apply but they wear out the quickest and should be reapplied at least once a year.
- Stains contain coloured pigments and are intended to change the colour or darken the decking. After a long time of exposure to sunlight, the colour of timber can fade and turn into grey. Decking stains are good for renewing the colour in these cases. Stains come in different variations; sometimes they can be combined with decking oil or a glossy sealant. Often stains are both, intensify the timber colour and protect against moisture and rain. Generally decking stains require more care in preparation of the timber and may take longer to apply.
- Acrylic coatings that build a film, cover the surface, seal the wood pores and do not penetrate into the timber like oils and stains. The biggest advantage is that they isolate the timber from any moisture and develop a shiny film. However, clear gloss finishes are sensitive to abrasion. Areas with frequent traffic can get damaged and the colour of the wood can turn grey, especially if there is sometimes sand or dirt on the timber deck and also the boards can get slippery when wet. Same as decking oils acrylic coatings for outdoor use contain colour pigments to block off ultraviolet radiation. Each time film building finishes are applied, they require comparatively high preparation of the timber surface but the service-life is much longer – they can last about three years.
- Paints are similar to acrylic coatings. They however cover completely the natural texture of timber because of their high content of colour pigments. On the other hand is it the colour pigments that basically isolates the timber surface from UV-light and thus paints protect wood against sun and rain pretty good. The service-life is hard to tell but in average paints should outlast about three years - if not longer.