Siberian Larch Tongue and Groove Cladding

Siberian Larch Tongue and Groove Cladding is available in a range of profiles including:

• IWC1 - 19mm x 145mm overall, with a 135mm face - For horizontal or vertical fitting
• IWC2 - 19mm x 95mm overall, with an 88mm face - For horizontal or vertical fitting
• IWC3 - 19mm x 142mm overall, with a 125mm face - For horizontal or vertical fitting
• IWC4 - 19mm x 145mm overall, with a 125mm face - For horizontal or vertical fitting
• IWC5 - 19mm x 145mm overall, with a 125mm face - For vertical fitting only

With the exception of IWC5, our tongue and groove profiles can be fitted either horizontally or vertically which is entirely your choice.

IWC5 is the only profile which must be fitted vertically. Also, if you want to use secret nailing to fix your cladding you can choose IWC3.

The Larch is supplied in Sawfalling and Unsorted grades and the colour can vary between pale reddish-brown to a brick red. Sawfalling Siberian larch is the lower grade and has a lot of character to it, making it a very attractive timber and its roots in Siberia mean that it is more than capable of standing up to English conditions.

Unsorted Siberian Larch is a lot cleaner in terms of knot content and is the highest we can supply in the UK.

Larch cladding is supplied in supplied in 3m lengths and longer. The lengths of your cladding will be random however where necessary we can try and get the exact lengths you need. If you do need exact lengths we ask that you check with us first (by calling 01889 279 018 or talking to us on the chat) so that we can make sure we can get what you want. If we can there is a “Special Instructions” box on the shopping basket page where you can enter your lengths.

Treatments

Be sure to read through our treatment information by clicking on "Treatment Guidance" above. It talks about sealing, preserving and protecting the timber from the sun's UV rays. Here are quick links to the products we recommend:

• Wood Preserver Basecoat - Barrettine Premier Universal Preserver
• UV Protection to Delay Weathering

Fitting Guidance

These fitting guidelines are only a rough idea on how to fix your tongue and groove cladding. We do recommend you employ a professional who has experience fitting tongue and groove cladding.

Be sure to read our treatment guidance as treatment needs to be applied prior to fixing your cladding

Breathable Membrane

Consult a fitter to determine if your scenario would require the fitting of a breathable membrane between your wall and the cladding. This membrane stops rain getting to the wall, but allows moisture to escape, helping to prevent internal condensation and mould that can come with it.

Treated Softwood Battens

Treated softwood battens (available from our cladding accessories pages) are most commonly used to fix to the wall (or on top of the breathable membrane) to then fix your cladding to. If you are fixing your cladding horizontally, your battens need to be placed vertically, at around every 600mm (60cm), and vice versa.

Fixing

** Whether you use nails or screws, it's important that they are stainless steel, or silicone bronze ARS, so that the natural tanins in the timber will not corrode them. Never use iron nails for fixing timber.

To help stop the wood from splitting we recommend pre-drilling the timber and then holding it with the screw or nail head when you fit the board to the batten. Look to leave a 3mm gap between the boards, rather than butting them up tight like flooring, to account for any moisture movement and make sure that the tongue is facing upwards otherwise moisture will start gathering in the groove of the profile.

You can also use nails, preferably ring-shanked for extra grip, and again stainless steel so they don't corrode. For lower-density species like cedar, consider using nails with larger heads so the cladding doesn't pull through.

You can fit IWC 1,2,3 and 4 vertically or horizontally depending on the look you want from your timber. Whilst technically you can fit IWC5 horizontally, water can sit in the square channel, which is not recommended.

With each new row of cladding you add, it's preferred that you stagger the joins between each board so you don't create a visible seam.

As already stated, these are just ideas to get you thinking about installation and you should consult a professional installer before fitting your cladding as every scenario is different.

Treating Timber Cladding

All of our timber cladding is provided untreated.

For best results, cladding should be treated before it is installed to ensure application of the treatment on all sides and ends of the boards.

We recommend Wood Finishes Direct for all of your treatments. We have found them to be well priced and their telephone support and advice is second to none. We highly recommend giving them a call.

The following information is from Wood Finishes Direct in relation to treating timber cladding.

When it comes to treating your timber cladding, there are three areas of protection to consider.

1. Sealing against moisture movement - Sealants are used to help prevent moisture entering the wood causing it to expand. Kiln dried timber like European Oak will definitely need to be sealed, and for other timbers it is highly recommended.
2. Wood Preserver - Helps to prevent rot and protects the wood from insect infestation and mould.
3. UV Protection - The ultraviolet rays of the sun slowly bleach external timbers. UV protection oil helps to keep the natural colour of your timber for longer and prevent it from turning silvery grey so quickly. Some people like their timber to weather and prefer the silvery grey look so it’s completely down to you.

The following links will take you straight to the products on Wood Finishes Direct's website:

Product to Seal and Preserve

To address Sealing and Preserving, they recommend applying one or two coats of "Wood Preserver Basecoat - Barrettine Premier Universal Preserver" before installation to seal against moisture movement and protect it from mould and insects.

Product to Protect from UV Rays

Then to optionally delay weathering, two coats of OSMO UV Protection Oil. There are different colours of OSMO UV Protection Oil available, with names like 'Cedar' and 'Oak', but these colours are to make other timber look like the stated species. We recommend the 420 clear version which interferes the least with the natural colour of your timber.