Multi Layered Timber
May 14, 2014
You'll often hear this term bandied around websites specialising in windows, doors or outdoor timber structures with very little explanation as to what it is, and fundamentally what it does. Simply put, it is the combination of three or more layers of timber which are glued together in order to combat the constant threat of swelling.
Whilst we always take steps to prevent this happening within timber products, through drying the timber or treating it with a variety of finishes like paints and varnishes, the problem will always be there. This is because wood is what we call a 'hygroscopic material', meaning that it will constantly try and reach an equilibrium with the moisture content of the surrounding atmosphere.
If you look into the cellular structure of timber you see that there are cavities between the cells, in which water is pooled when it becomes more humid. This is so that trees, when they are growing, can absorb wood without saturating the cells which would otherwise kill them. The problem is that once they are dead, they still do it.
When timber takes on excess water we call it 'movement across the grain', meaning that the timber swells in a certain and predictable direction. By multi-layering sheets of timber, with each layer prone to moving in a certain direction when it swells, we effectively negate the effects of water absorption across the structure, removing the threat of the windows jamming or warping.
Advantages of using this technique are many, with its design features appearing at the top of the list. Utilising mutli-layered timber means that we still get to retain the product's organic beauty, whilst also gaining a material that is far stronger and more reliable than single layered timber frames.
It also means that we don't have to seek unsustainable alternatives which can also give us the same reliability. So we're winning on both fronts!
Multi-layered timber is as easy to work with as any solid wood, though the cost is slightly higher and the prep time slightly longer. However, it does mean that we basically don't have to worry about water absorption any more; meaning that we can create intricate and intuitive designs that we otherwise couldn't. With an increased guarantee, greater durability and further scope for design, it's quite simple the way to go!