tThermally modified wood as a decking material

Thermally modified wood is an environmentally friendly and durable decking material. In the heat treatment process, no chemicals are added to the wood, but the wood's properties are modified by high temperature and humidity.

In this article, we will tell you about the properties of Thermally modified wood and give you a few tips for choosing decking products.

Six reasons to choose thermally modified wood as a raw material for yard construction

Weatherproofing
During heat treatment, the cellular structure of the wood is compressed, so the wood does not absorb as much moisture as normal wood. Thermally modified The moisture properties of wood are therefore better than normal for construction.
Minimal formatting
Thermally modified wood is very dimensionally stable, and its width deformation is much less than that of ordinary wood.
Chemical-free and non-toxic
Thermally modified wood is ordinary wood that has undergone a drying and heat treatment process, without any chemicals or toxins added during the treatment. This makes it not only an environmentally friendly choice of raw material for yard construction, but also a safe raw material to handle and process.
Long service life
Thermally modified the wood has a long lifespan, as its resistance to decay is much better than that of ordinary wood. Rot resistance goes hand in hand with good weather resistance, as moisture is less easily absorbed by the wood.
The wood is stained
Thermally modified the wood's characteristic brown colour is the result of drying, heating and humidity equalisation, so that the colour permeates the whole wood. Any dents or other wear on the surface of the decking board is therefore not aesthetically disturbing, as the wood underneath is also brown thanks to the heat treatment.
Almost straw-free
During the heating and drying phase of the heat treatment process, most of the wood resin is removed, so thermally modified wood as a building material does not get messy, at least not because of resin. As a result, heat-treated decking boards remain mostly resin-free even when installed in sunlight.

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How is thermally modified wood made?

The heat treatment process uses only heat and water vapour - so no additional substances are added to the wood.

The first step in heat treatment is drying the wood. It involves slowly adding heat to the wood, which reduces its moisture content to zero. This is followed by the actual heat treatment, where the wood is heated to over 200 °C and its cellular structure is slightly compressed.

In the final stage of the heat treatment, 4-7% moisture is added to the wood through pressure and temperature. The wood is levelled, planed and post-treated as planned.

Thermally modified wood surface treatment

Thermally modified the original brown colour of the wood will last longer if you oil the surface. Oiling also reduces the risk of splintering and cracking, especially if the wood is exposed to weathering - for best results, keep your decking clean and oil your decking annually. You can also choose not to oil your decking made from heat-treated wood, but this will cause the wood to turn grey more quickly.

Concealed fixing or top fixing of decking boards? With Thermodeck terrace products you can choose according to your preferences

With Siparila Thermodeck products, you will receive installation instructions to ensure that the product you choose will perform to the best of its ability. Here are a few tips to help you decide whether top or concealed mounting of the decking boards is more suitable for your terrace.

Fixing from above

Fixing the decking boards from the top is a very traditional method in Finnish yard construction, and the fixing points on the decking boards are not usually distracting to the eye, as we are so used to them.

Siparila's Thermodeck terrace products also include top-fixing options(Classic and Elegant), and often top-fixing is a quicker way to build a terrace than other options. Thermally modified With wood, top-fixing also poses no challenges with moisture, as the wood is weather-resistant throughout - both on the surface and in depth.

If you choose a top-fixing decking board, Thermally modified , we recommend pre-drilled holes at the installation stage to prevent the wood from splitting.

Concealed fastening

If you enjoy aesthetically beautiful and finished surfaces, you should definitely opt for concealed fixing decking boards(Siparila Thermodeck Classic or Elegant).

Siparila's Thermodeck terrace products are based on a hidden fastening system based on a clip placed between the terrace boards, which in turn is screwed to the terrace support structure. The clip prevents lateral movement of the decking piece.

Thanks to the concealed fixing, the surface of the decking board is beautifully uniform as the screw or nail heads are hidden between the boards. The concealed fixing also means you can't scrape your foot on a raised screw or nail. Concealed fastening is a little slower than top fastening, but the end result is sure to be finished.

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What can wood be used for in the construction of yards?

Thermally modified In addition to wood, Siparila's range also includes a wide variety of products, for example, for exterior cladding, screens and fences.