Thermowood – The Ultimate Guide to Thermowood in 2023

Thermowood is timber that has been treated with heat hence why it’s also called Heat treated Timber. It is a beautiful, sustainable timber material produced using chemical-free heat treatment. Making buildings more sustainable is becoming more and more necessary which increases the demand for materials like Thermowood.

It is an extremely versatile construction material that has both interior and exterior cladding installations. Some of the more interesting and probably more recognisable uses are for the inside of saunas and outdoor decking. They are also becoming a more increasing popular for both internal and external cladding.

How is Thermowood Produced?

Thermowood is created by heat treating Scandinavian softwood to temperatures ranging from 180 – 230°C in special chamber kilns for up to 96 hours.

Steam is used as a protective gas and helps to prevent the wood from splitting and becoming damaged during treatment.

What type of Softwood is used for Thermowood?

Scandinavian softwood is also known as European Redwood or Scots Pine. It’s a high-quality softwood that’s also both dense and durable. This makes it a reliable yet attractive timber for construction.

Our timber is sourced from sustainable, PEFC-certified forests, and as no chemicals or foreign substances are involved during its production. This ensures that you get the very best of timber cladding.

Does Thermowood Fade and can you Paint it?

This depends on the type of timber used but yes, if Thermowood is left untreated then it’s colour will slowly fade to a light grey or ‘washed grey’. This colour change is caused by the Sun’s UV rays.

As Thermowood is expected to have a prolonged life, it doesn’t necessarily need a surface treatment applied to it. Some people choose to add a finish, stain or paint to their timber to enrich its colour.

As is the case with all wood building materials, timber cladding maintenance is important for the lifespan of the wood. Treatment and other maintenance can help prevent the wood from decaying, this is especially the case with Thermowood because it is a softwood.

Thermowood Characteristics & Benefits

The treatment process causes chemical and structural changes to occur within the timber, which therefore alters some of its characteristics and qualities. Some of the characteristics and qualities that make Thermowood such a popular type of material include:

Dimensionally Stable – The intensive heat that the wood is exposed to during its production dries out deep into the core, causing all moisture and resin to be removed from the timber. This makes it a great material for outdoor timber decking. Thermowood therefore doesn’t react to changes in humidity as drastically as untreated wood (the risk of swelling, cracking and shrinkage is decreased), allowing it to retain its shape far better. The wood also doesn’t secrete sap or resin even in high temperatures.
Environmentally Friendly – The softwood used to produce Thermowood originates from well-managed, PEFC-certified forests, and as no chemicals or foreign substances are involved during its production, Thermowood is an environmentally friendly material produced by using only natural methods.
Resistance to Rot and Fungi – Due to the heating process breaking down hemicellulose, the wood doesn’t contain the appropriate nutrients to allow rot and fungi to grow and develop.
Increased Longevity – When wood is treated with heat, its average life span is prolonged. It will depend on the exact heat the wood is exposed to as to how long it is expected to live, but generally the higher the temperature, the longer the life span.
Improved Insulation – Wood that has been heat treated is much more porous than untreated wood, vastly improving its insulating properties.
Sustainable – Unlike pressure impregnated wood, Thermowood can be discarded or recycled as untreated wood when it is no longer required.

Thermowood Uses

The thermal modification of wood improves the wood’s properties, thereby expanding the range of applications in which the wood can be used.

As mentioned earlier, Thermowood is one of the more affordable options for exterior and interior construction materials and is very versatile.

External Uses

Its high resistance to moisture and decay makes it an excellent material for exterior projects. Some of its most popular external uses include:

External Cladding
Decking
Louvre Blades
Brise Soleil
Interior Uses

Its attractive appearance and removal of resin means that the timber is also ideal for interior projects, such as:

Interior Cladding
Saunas
Furniture
Flooring
Thermowood Cladding Appearance

The colour of Thermowood is affected by the temperature the wood is subject to and the length of time it is exposed to the heat. There will be a slight variance in colour due to different softwood densities, but generally, the higher the temperature the wood is exposed to, the darker the Thermowood.

Thermowood Cladding Installation

Thermowood Installation usually involves fixing back to timber battens, and in turn to attach the pieces of Thermowood to.

Stainless steel screws should be used as they are more weather and moisture resistant. These are used to fasten the Thermowood and can be instrumental in the design of the finished product if it is abstract (such as unique interior design cladding).

Does Thermowood need to be sealed?

Thermowood has been heat treated so it’s not as vulnerable to moisture as standard wood. Because the wood has been altered on a molecular level, it’s not necessary to seal it. As mentioned earlier, it can still be beneficial to add wood oil and other treatments to help maintain its colour or prevent decay.

Thermowood Prices

Thermowood is generally cheaper than most hardwoods, or other softwoods such as Canadian Western Red Cedar, making it a very affordable and popular material for most homeowners and developers. The production process doesn’t involve any chemicals, meaning that it is less expensive to produce.

However, for the best and most competitive Thermowood prices, we strongly recommend getting a quote from one of our timber specialists today. No matter how much timber you need, or what project you are undertaking, our friendly team will be more than happy to help.

If you are not entirely sure as to whether Thermowood is the most suitable timber material for your project, please don’t panic! We supply a wide range of timber species, so whatever your project entails, we are sure to have a suitable wood specie that ensures you get the results you are after.

Our team are also able to discuss the logistics of your build and help make sure that you have everything you need.

Thermowood Cladding Suppliers

Here at NORclad, we are one of the leading suppliers of Thermowood cladding in the UK. With over 40 years of experience in sourcing, developing, manufacturing and distributing sustainable products, we are experts in the field and first port of call for architects, designers, contractors and builders.

We specialise in supplying not only Thermowood cladding, but a range of specially developed timber cladding products, including European Redwood and British Larch.

Thermowood Cladding with NORclad – The Timber Cladding Experts

If you’re looking to purchase the highest-quality Thermowood, please don’t hesitate to get in touch or request a quotation today. We offer a wide range of grades and profiles, so whatever your project, we’ll be able to help!

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See more: Importance of PEFC and FSC Certification in Timber Cladding