We are often asked if new timber should be stained?
The answer is yes and no.
Yes, in that it is always a good idea to look after your timber, and timber loves penetrating oil based stain, but no it shouldn’t be stained immediately.
If you are planning on staining, and especially if you are going to paint your new timber, it is best if it has a pre-treatment to remove all the building dust and dirt and the residues from the treatment process. The “tanalising” process (to use an out-dated phrase, but one everybody is familiar with) will have left the timber wet or green, it needs some time to dry out. There will also be some tannins in the surface layers, some sap if it is pine, and what is known as “mill glaze” from machining (that is what makes the timber look shiny).
Pine The pre-staining process is relatively simple for pine, fences, decks and retaining walls. The timber is sprayed with a highly alkaline cleaning solution (this is hazardous at the concentration required, but the compound is used for making soap and treating drinking water amongst other things) and allowed 15 minutes of dwell time, then washed off. The timber is then sprayed with a neutraliser to bring the pH down to around 6.5 and then washed off. After 2 days of dry weather the timber is ready for staining. As with all new timber the fibres in the timber are still very tight so a mineral oil based penetrating stain applied thinly in two coats is recommended. If you want a paint finish on your new fence then I suggest you use dressed timber, although it is much more expensive, it will look much better. The treatment process is identical.
Kwila When your new and expensive Kwila decking first goes down it will look amazing. That is due to the colour and grain of the finished timber. That colour is due to the very high levels of tannin in Kwila, but it will “bleed” out a great deal of that colour as soon as it is rained on. The red colour is so strong that it will stain anything it bleeds onto, so don’t leave any offcuts on a concrete drive or path as it will stain it. We don’t usually recommend staining Kwila when it is new as a} it already looks great, and b) the stain won’t penetrate anyway. Our recommendation is to leave it for 6 months or until it has changed to a grey colour at which time all of the surface tannins will have washed out and the fibres in the timber will have loosened sufficiently for a stain to penetrate into the timber. The process at this time is a standard Deck Clean and Stain. If you prefer the grey/silver look, then a clean only is acceptable, but after a few years the Kwila, like all timber, will start to cup and crack.
Cedar Cedar should be sealed with specific sealer that contains a fungicide on all sides BEFORE it is put up. This is an easy and reasonably quick job, although every builder I know hates doing it. My opinion is that it should also have two coats of a mineral oil based penetrating stain applied to the exposed face prior to being nailed up. If this is not possible (the usual situation) two coats should still be applied as soon as possible. Cedar will weather to grey/silver quite quickly, especially if it hasn’t been stained with a penetrating stain that has pigmentation (colour) in it. If you want to maintain the cedar colour it will require cleaning and re-staining approximately every 5 years, possibly more often on the North side. The South side will retain its colour but will be susceptible to mould and algae, so should be washed at least once per year. Even with correct staining and maintenance the tannins in cedar will leach out with exposure to rain and sun. Under the eaves it will appear a lot darker than the rest of the cladding, this is due to not being exposed to the sun and rain, so even though the tannins have come out of the cedar, it hasn’t been washed away. If cedar isn’t maintained it will cup, crack and splinter within 5 to 7 years. If this occurs badly enough the cedar will no longer be water-proof (and the last thing you want is a leaky home) and will be beyond restoration. Re-placement at great expense is the only option.