Tongue and Groove Cladding

Which tongue and groove should I choose?

For outside walls, Air Dried Oak is air dried European oak, supplied untreated, and weathers to a silver-grey, and Douglas Fir is a lower-cost British-grown softwood alternative to oak. The two Thermowood boards are thermally modified with heat and water only, with no chemicals, and can go inside or out. For tongue and groove panelling on inside walls and ceilings, choose kiln dried oak or our thinner kiln dried matchboard (interiors only), or either Thermowood. For farm buildings, see Heavy Duty Tongue and Groove / Dungboards in agricultural cladding.

Grades and end matching

Oak and Douglas Fir T&G come in Character grade, with sound knots and natural variation, or First grade, which is cleaner. The Thermowoods are Character (Redwood) and Prime (Radiata pine). End matching puts a tongue and groove on the board ends as well, so joints can fall between battens rather than on one. It's a paid option on most boards that speeds up fitting and cuts waste.

Finishes

Our external boards are supplied untreated. Left alone they weather to a silver-grey; to hold the colour for longer or add a weather-resistant finish, see our cladding treatments.

Fixings, trims and samples

Use stainless steel fixings with oak, as its tannin reacts with ordinary steel and causes dark stains; use stainless or coated fixings with Douglas Fir. See our cladding fixings, finish corners and edges with trim boards, and order a cladding sample if you're not sure which timber to choose. If you want a V-shaped joint line instead, see V tongue and groove cladding, or for overlapping boards see shiplap cladding.

FAQ

What is tongue and groove cladding?

Boards with a tongue along one edge and a groove along the other. The tongue slots into the groove so the boards lock together for a flush finish.

Can I fit tongue and groove horizontally or vertically?

Either. If you fit it horizontally, put the tongue uppermost so moisture runs off.

Which tongue and groove can I use outside?

Air Dried Oak, Douglas Fir, Redwood Thermowood, Radiata Pine Thermowood and Douglas Fir Matchboard. Kiln Dried Oak and the kiln dried matchboard are for interiors only.

What sizes do you sell?

Air Dried Oak at 120 or 142 × 20 or 24 mm, Douglas Fir at 142 × 20 or 24 mm, both Thermowoods at 142 × 20 mm and Kiln Dried Oak at 120 or 142 × 20 mm. Matchboard comes in 120 × 12 or 16 mm.

What is end matching?

A tongue and groove on the board ends as well as the edges, so joints can fall between battens. It's a paid option on most of our T&G boards, chosen from the dropdown on the product page.

What is the difference between tongue and groove and V tongue and groove?

Both lock together with a tongue and groove. V tongue and groove adds a chamfer on each edge so each joint shows a V line; standard tongue and groove gives a flatter, closer joint.

How is it priced and delivered?

Most boards per m² ex VAT, and matchboard and dungboards per board ex VAT. UK delivery in up to 10 working days on our own crane offload vehicles, nationwide, or collect from Corby.