Wood: Cladding, Tongue and Groove Boarding and Fencing

Shiplap cladding

The most common type of exterior wall cladding is shiplap, which is designed so that the boards interlock (right).

Shiplap is in standard sizes, all nominal, of 19 x 100 mm (3/4 x 4 in), 19 x 150 mm (3/4 x 6 in) and 25 x 150 mm (1 x 6 in).

Shiplap made from timber other than cedar needs to be painted, or treated with regular applications of wood preservative.

If the work is to be painted, prime all faces of shiplap before fixing, paying particular attention to the ends.

Shiplap has fair insulation properties. For the best protection against weather, first nail a layer of building paper to the brick or block wall, then nail treated timber battens vertically against the paper, 400-450 mm (16-18 in) apart.

Fix the cladding to the battens with galvanised lost head nails. Punch all nails below the surface before painting.

Tongued and grooved boarding

The commonest sizes, in deal, are 19 and 25 mm x 100, 125 and 150 mm (¾ in and 1 in x 4, 5 and 6 in). Points to note are as follows:

1. The tongue is shorter than the depth of the groove, to ensure a tight-fitting joint.

2. The tongue and groove are not cut centrally in the thickness of the section. Fix it with the greater distance from face to tongue uppermost, so that the boards can be re-sanded frequently before exposing the joint.

3. The narrower the boards, the more joints there are to take up shrinkage: wider boards leave wider gaps.

4. Wherever possible, buy all the tongued and grooved you need for each job at the same time, from one batch of machined timber. This will ensure that the sections fit exactly. The chances of sections from different batches being exactly the same are extremely remote.

5. Tongued and grooved boards can be nailed through the face or secret-nailed. Use lost head or oval nails

6. When laying tongued and grooved timber, fix the first piece with its tongue ready to receive the next board.

7. When driving the boards into one another, use an offcut over the tongue to prevent the hammer damaging the tongue.

8. Block, strip and plywood floorings are available tongued and grooved.

Tongue, V-joint and groove

This boarding is used mainly for joinery, wall and ceiling cladding, cupboards, gates and soffits.

There are two types, close and open: the latter has an elongated tongue that gives a grooved or ribbed effect. Both types can also be obtained with a moulded face that gives an added contour.

The open and its moulded variation can be obtained from a small number of merchants as stock. Otherwise they must be machined to order. Note that the nominal size includes the tongue, so that the actual covering width is some 15 mm (5/8 in) less than the size quoted.


Dry the boards out before lining walls and ceilings, as shrinkage can cause the tongue to disengage from the groove.

Fix in the same way as tongued and grooved boarding.

Fencing (hardwood and softwood)

Boards, featherboard or weatherboard, overlap by 20-25 mm (¾-1 in). They are fixed with galvanised wire nails. Sawn sizes of 19 x 115 mm (¾ x 6 in) and 19 x 150 mm (¾ x 6 in) are common. They are usually of home-grown softwoods or oak and are available in lengths from 900-1800 mm (3-6 ft).

Gravel board is usually 19 or 25 mm x 150 mm (¾ or 1 in x 6 in). The boards can be obtained already impregnated with creosote.

27. June 2011 by admin
Categories: Timber, Woodworking | Tags: , | Comments Off on Wood: Cladding, Tongue and Groove Boarding and Fencing


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