Thermowood SECRET-FIX Shiplap Cladding - 19mm x 117mm

  • £5.04

  • Ex Tax: £4.20
  • Product Code: FORTW19117SHSF
  • Availability: Pre-Order
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Special order, lead time 5 - 7 working days

Description: A/B grade Thermowood (Pine) Secret-Fix Shiplap cladding (covers 97mm). The thermal modification process (without chemicals) of the timber makes it durable for external use above damp proof course. Thermowood is a more knotty lower cost alternative to cedar cladding.Use horizontally not vertically.

Our Thermowood cladding is classified as Durable (Durability Class 2) and comes with a 30 year expected service life, as endorsed by the Building Research.

Super smooth machined finish

Chemical free and can be disposed of as you would any clean un-treated wood

The wood absorbs far less moisture. Meaning shrinkage and swelling is dramatically reduced making it one of the most stable claddings

The heat treatment process disperses all resins from the wood, and thus resin bleed through paint finishes is eliminated


The wood becomes slightly more acidic in nature, and thus is advisable to only use stainless steel fixings to fix it

A/B grade Thermowood which is traditionally sold in the UK is produced from the centre of the original tree/log, so expect a knotty visual appearance - wing shaped knots are the norm.

The high temperature the timber is subjected to can cause dead knots to loosen and some live knots to crack. Over a 3.0m length up to three B grade missing dead knots and or lightly cracked live knots are permissible on the top/decorative face of boards. Any amount of loose dead knot, badly cracked live knots and or surface shake (splits) are permissible on the reverse face.

The original brown colouration weathers to grey over a relatively short space of time. In the interim it is normal for the surface of the thermowood to become colonised by mould spores that appear as small dark spots. These will also fade overtime. If a coated finish is required we recommend the use of the non-film forming Aquadecks and Protext by Owatrol a translucent matt finish available in a variety of shades that will slow the greying effects of U.V. light.

The smokey smell of the wood dispels with time or as soon as a coating is applied

It is not suitable for use where it may be saturated with water or in ground contact

It cut and works well with traditional work working tools. However the heating process makes the wood more brittle meaning fixings should not be secured without first pre-drilling pilot holes especially near the end grain of boards.

Price is per linear metre.