THERMOWOOD

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Heat treated wood, so called Thermowood, is an environ­

mentally friendly alternative to pressure impregnated

wood. The heat treatment has many benefits, such as

making the wood more resistant to rot and fungi,

increasing stability, causing less cracking and providing

better insulation.

The finished product is great for outdoor use as it with­

stands tough weather. Common uses are outdoor

panel ing, wooden decks, doors, windows, fences and

outdoor furniture. The golden brown colour also makes

it a popular choice for indoor use, such as for furniture,

floors and wood paneling.

Our Thermowood is licensed by The International Thermowood Association. The Thermowood Association owns the patent for Thermowood and controls the licensed manufacturers once or twice every year. Be sure to choose a licensed Thermowood retailer in order to ensure that you get a top quality product.

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What is heat treated wood?It has long been known that burned wood has increased

stability and is more resistant to rot and fungi. Even the

Vikings burned the wood they used as piles when building

jetties to make it last longer. Unfortunately, burning the wood

made it dry and brittle. A technique has now been developed

which has solved those problems. Today’s heat treated wood,

Thermowood, has many benefits such as resistance to rot and

fungi, stability and a lack of chemicals to name but a few.

The heat treatment can be used on many types of wood.

How the heat treatment is done:1. The wood is heated to 212 degrees Celsius. The treatment is ended

before the wood becomes charred.

2. The heat treatment changes the wood’s chemical structure and hence its properties. This treatment improves several of these properties, such as stability, resistance to rot and fungi as well as improved insulation.

3. he result is a wood that is golden brown all the way through. If exposed to direct sun light without any surface treatment it will gradually turn a beautiful silver grey.

Difference in shade between heat treated (left) and un­treated wood (right)

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Why choose heat treated wood?There are many reasons for choosing heat treated wood.

Below we have listed some of the benefits created by this

process.

Resistance to rot and fungiDuring the heating process the nutrients in the wood are destroyed, making it very difficult for rot and fungi to develop and grow.

More stabilityHeat treated wood contains very little fluid and absorbs less liquid than untreated wood, increasinging stability by up to 50 percent.

Improved insulationHeat treated wood is more porous than other wood which improves the insulating properties by 25-30 percent.

Environmentally friendlyNo harmful chemicals are used in this process, thereby avoiding any harmful environmental impact. The wood used is prime quality, knot free pine which comes from certified forests in northern Sweden.

Old wood can be discarded or recycled as untreated woodYou can burn or recycle Thermowood as you would any regular wood, as opposed to pressure impregnated wood or NTR-classified by the Nordic wood preservation council (Nordiska TräRådet), which must be deposited as toxic waste.

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. Tropiska träslag transporteras även de långa avstånd samt kan i vissa fall komma från miljömässigt tveksamma skogsbruk. Tropiska träslag kräver ofta ursprungs-certifikat och andra dokument för att få säljas.

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Longer life spanWhen wood is treated with heat the life span is prolonged. The higher the temperature the longer the life span. The strength, however, decreases which is why it is very important to buy heat treated wood from a licensed manufacturer.

Less crackingAs the heat treatment increases the woods stability, it decreases the risk of cracking.

Alternative to cedar and tropical woodThermowood is the perfect alternative to imported wood, such as cedar and larch or tropical wood. The reason for this is that cedar is transported over long distances, often from Canada. The tropical wood is also transported long distances and may be grown in questionable forests with regards to the environmental issues. The tropical wood often requires certificates of origin and authenticity as well as other documentation in order to be legally sold.

Coloured all the way throughAfter treatment, the wood has a golden brown colour all the way through which means that it can easily work by cleaving or sanding without any noticeable colour difference.

No sapThis product is free from sap as the heat treatment eliminates it. As there is no sap, there is no risk of the paint coming off as sap is released.

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Product range and areas of useThermowood is most suitable for products that need to

be weather resistant, such as outdoor paneling, wooden

decks, doors, windows, fences and outdoor furniture.

Naturally Thermowood can be used indoors as well.

It is often chosen due to its stunning colour, stability

and its lack of sap. By all means use Thermowood for

your sauna, wood paneling, floors and furniture.

Thermowood is excellent to use in saunas as it is free from sap and offers thermal insulation.

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Name Top layer Measurements Profile Length Lm/m2 L/L/B*

Decking Grooved 26x92 3,9–4,5 m 10,87 L

Decking Grooved 26x118 3,9–4,5 m 8,48 L

Stud Planed s4s 42x42 3,9–4,5 m L

Stud Planed s4s 42x92 3,9–4,5 m L

Stud Planed s4s 42x141 3,9–4,5 m L

Sauna bench Planed s4s 26x92 3,0 m B

Sauna paneling Planed s4s 15x92 3,0 m 12,2 B

Clapboard Sawn 21x118 3,9–4,5 m 9,81 B

Clapboard Sawn 21x141 3,9–4,5 m 8,0 L

Tongue and groove paneling 30° 10 mm Sawn 21x118 3,9–4,5 m 9,71 B

Tongue and groove paneling 30° 20 mm Sawn 21x141 3,9–4,5 m 7,94 B

Tongue and groove paneling 90° 8 mm Sawn 21x141 3,9–4,5 m B

Tongue and groove retaining wall 45° 0 mm Sawn 21x118 3,9–4,5 m 9,26 B

Tongue and groove retaining wall 45° 0 mm Sawn 21x141 3,9–4,5 m 7,64 L

Tongue and groove retaining wall 45° 0 mm Planed s4s 21x118 3,9–4,5 m 9,26 B

Tongue and groove retaining wall 45° 0 mm Planed s4s 21x141 3,9–4,5 m 7,64 B

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Thermowood can be specially made to any measurements and shapes.

*In stock/Ordering

Rollodeck

Perfect for the bathroom, basement or balcony.

The Rollodeck is held together by rubber bands

which keep the sections in place and make sure

they do not glide. There are two different lengths,

580x780 mm and 580x1560 mm and longer ones

can be made to order.

Fence

Thermowood fence Forsa.

Width 150 cm, height 80 cm.

Thermowood fence Hambo

Width 150, height 70 cm.

Thermowood pole

90 x 90 x 1000 mm

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About Teknos Woodex glazeAs heat treating wood is very

popular in Finland the Finnish

Thermowood Association has col­

laborated with the paint industry

collecting information on various

finishes of heat treated wood. One

result of this is Teknos Woodex

series which we use to profession­

ally treat the wood. This series also

protects the wood from mildew.

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Industrial treatment Do it yourself

For maintaining the colour (brown)

Tekno Aqua TM 1703 (teak) Woodex oil (teak) or other pig-mented oils

For a silver gray tone (natural)

Sioo waterproofing (Sioo wood preservative and weatherproofing*)

Sioo waterproofing (Sioo wood preservative and weatherproofing*)

*An additional layer of protective agent can be applied after approximately one year to improve the life span.

Maintenance and recommendationsThe sun’s ultra violet rays affect all wood, including heat

treated wood. In order to preserve the golden brown colour

the wood should be protected by waterproofing or by treating

it with pigmented oil. If one chooses not to treat the wood

against the sun’s rays the colour will slowly change to a

beauti ful silver grey tone.

One can treat the wood oneself or have a professional do it. Treating the wood in one of these ways will also make it more resistant to dirt and mildew. Mildew can grow on any surface that is damp and contains nutrients which is why it is recommended that the wood be treated against mildew if it used in damp environments.

Industrial treatmentIf one wants the Thermowood to be professionally treated before delivery we use Teknos Aqua 1703 in order to preserve the golden brown tone. If the silver grey tone is preferred the Thermowood can be treated with Sioo waterproofing.

Treating the wood at homeIf one prefers to treat the Thermowood oneself any pigmented oil can be used. One can also purchase the eco-labelled Sioo waterproofing (dual components) and apply it with a brush or a sprayer.

MaintenanceIf needed, Thermowood can be cleaned with a gentle cleaning product such as liquid soap. If the wood is very dirty one can use a pressure washer, but this should be done with caution. It is highly unusual that the wood turns blotchy, however should this happen it can be sanded in order for it to regain its original appearance.

About Sioo water proofingSioo waterproofing is a dual

component product free from toxic

chemicals or solvents which pro­

tects the wood for as long as ten

years. As Sioo does not bind any

moisture in the wood it continues

to breathe naturally after water­

proofing. Apart from protecting the

wood, the product also enhances

the surface of the wood creating

an even, light colour and shine.

This way the darkening of the

wood which one gets from treating

it with oil can be avoided. It also

protects the wood from mildew.

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Klass 1Mycket beständigt

Klass 2Beständigt

Klass 3Måttligt beständigt

Klass 4Ringa beständigt

Klass 5Icke beständigt

Teak Western Red Ceder Sibirisk Lärk Europeisk Lärk Ask

Merbau Europeisk Ek Douglas Fir Gran Bok

Jarrah Thermowood® Valnöt Furu Lönn

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Processing and assemblingUse sharp toolsAs the heat treatment makes the wood more brittle, we recommend the use of sharp tools when working with the wood. We also recommend that one always pre-drill when using screws or nails close to the edges to avoid cracking.

Rust free nails and screwsThermowood has a slightly lower pH value than untreated wood which can lead to discolouration. To avoid this we recommend the use of rust free nails and screws such as stainless steel.

GluingTests from using glue on Thermowood show that it can be used in the same way as on any other type of wood with the exception of PVA glue. As this glue is water based it requires a much longer pressing and curing process. When using PU glue it is necessary to use extra amounts of water as Thermowood has lower moisture levels than other wood.

StrengthThe strength and solidity are lower in heat treated wood which is why it is not suitable for constructions requiring a certain stress grade in the wood.

ResistanceThe biological resistance to degradation, also known as the natural resistance, varies enormously between different types of wood. Because of this there are three standards used in classifying wood. EN 350-1 is of particular interest as it shows the natural resistance of the heartwood in hundreds of commercially interesting types of wood.

Class 1Very resistant

Class 2Resistant

Class 3Moderately resistantt

Class 4Barely resistant

Class 5Non resistant

Teak Western Red Ceder Siberian larch European larch Ash

Merbau European Oak Douglas Fir Spruce Beech

Jarrah Thermowood® Walnut Pine Maple

Source: Luleå Technical University

The table above only includes wood free from chemicals. Pressure impregnated wood uses other classifications developed by the Nordic wood preservation council (NTR – Nordiska TräskyddsRådet). When comparing pressure impregnated wood and Thermowood it has been noted that Thermowood has the same or even better resitance.

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