Articles: Ideal Time to fit External Cladding

As we move steadily through October the weather has definitely started to turn. It’s colder - and most definitely wetter - which would leave most looking for indoor work. On the most part this would be the best thing to do, however, it may be the best time to fit cladding.

The colder, more humid conditions are ideal for fixing timber to a wall. It not only gives the timber time to acclimatise before the warmer weather. Fresh sawn cladding, like feather edge or the machined British timbers will also be a lot more stable initially because they won’t dry out quickly because of the moisture in the air.

So when it comes to the summer, there will be less movement because the timber has already been in situ for so long. The wood will still shrink though as it dries, and then expand again during next year’s Autumn and winter.

What about Kiln Dried Products

We recommend treating all of our cladding products, however, this process is essential with kiln dried products like machined Oak, Canadian Douglas Fir and unpainted Thermowood. This is because if moisture gets in then they will expand which will cause issues with the integrity of the cladding due to the wood not being dries naturally.

There are many different ways to seal external cladding, you can either use a UV protector like Osmo 420 or you can a clear sealant that will still allow the timber to turn silver grey. The third option would be to apply a stain to the wood. For more information see our wood finishes page.

Whichever option you choose, it is important to treat all four sides and both ends before fixing so it is sealed correctly. If you just seal the face after it has been fitted you may get mould build up on the face as water gets into the wood and can’t escape from behind the seal.

How should I be fixing External Cladding

External cladding should be fitted using stainless steel nails or screws, and where possible, it is best practice to predrill the holes in the wood, although a nail gun can also be used. We recommend having fixing battens every 400 – 600mm behind the timber and it may be worth investing in a breathable membrane. This will sit behind the cladding and allow the timber to breath. This helps reduce mould build up on the back face and protects the wood from rotting.