Tanalised timber and pressure treated timber are actually exactly the same thing. They both refer to wood that has been specially treated with a mixture of chemicals to make the timber more durable and long lasting. This treatment is done under pressure which forces chemicals into the wood (thus “pressure treated” wood), and generally involves a chemical called Tanalith E (thus “tanalised” wood). Tanalith is a brand name of the chemical, the actual chemical used in the process may be a relation of Tanalith E, but one that gives the same result.

Wood that has been tanalised or pressure treated will be more resistant to rot, fungus, mould, and insects, as well as hardier in extreme weather conditions.

How Long Does Tanalised Timber Last?

That’s difficult to say since a lot will depend on how timber is treated. A shed that’s on top of a windy hill in a very cold climate might not last as long as one in the sheltered corner of a garden. But circumstances aside, tanalising timber should mean that the wood is rot proof for a good number of years.

How Do I Treat Tanalised Wood?

You do not have to treat tanalised wood, though it is recommended for a couple of reasons. Firstly, your timber will last longer if you choose to do some maintenance. Secondly, tanalised or pressure treated wood tends to change colour over time. If you wish to avoid wood turning grey as it ages, then treating it will help.

It’s recommended that you treat your timber with a tanalised timber treatment that you can buy at most DIY stores. This treatment simply paints on over the wood and is simple to use. For the first year of ownership, you shouldn’t need to do anything. After that, an annual coat of treatment will keep your timber looking good and mean that you get much more wear out of it.



Can I Paint Tanalised Wood?

Absolutely! Painting tanalised wood not only makes your garden look great but also gives the timber an added layer of protection, which can only be a good thing. However, you do need to be careful when painting pressure treated timber.

You cannot paint freshly tanalised wood, since moisture in the timber will mean that the paint won’t stick properly. You’ll need to buy some pressure treated wood preservative and paint that on to seal the wood first. These preservatives do vary, so make sure to read the instructions. These instructions should tell you when it’s appropriate to paint on the preservative, how many coats you need, and how long you need to wait before applying paint.

Is Tanalised Timber Waterproof

Tanalised timber is not waterproof, so it is still subject to the natural expansion and contraction as the moisture content in the surrounding atmosphere changes. It advised that a water repellent (clear or colour) treatment is applied to not only maintain the appearance of the building but also to help to exclude moisture being absorbed by the timber surfaces and causing it to leak.