Species

Cladding is easy to fix and provides a durable and effective covering for exterior building facades and can create decorative interiors.

A wide range of hardwoods and softwoods, is suitable including:

• Pine (or redwood)
• Spruce (or whitewood)
• Larch (can be used untreated)
• Western red cedar (can be used untreated).

Sizes

Thicknesses are available from 8mm (generally for interior use) up to 50mm (for exterior use), with widths from 100 - 175mm in lengths from 1200 - 5700mm.

Treatment

Softwoods, like pine and spruce, should be pressure treated with products such as Protim Clear Choice www.osmose.co.uk or Vacsol Azure www.archtp.com, although larch and western red cedar can be used untreated if the sapwood is excluded. To avoid the bleaching effect of ultra violet light, protect by using a pigment coating.

Finishes

Factory pre-finished cladding is now available. If finishing yourself, use woodstains (for exterior use) and water based lacquers (for interior use). For more information visit www.sikkens.com and www.sadolin.co.uk

Fixing tips

Ensure any cut ends of cladding are treated with preservative.

Fix onto pre-treated battens, which should be at least 38mm wide, 19mm thick and fixed at 600mm centres, ensuring joints meet centrally on a batten.

Allow for draining and ventilation in the cladding.

Use timber at least 150mm wide; tongued and grooved or rebated cladding for vertical installation, shiplap style cladding for horizontal installation.

Always base coat the back of the cladding before fixing. Consult BS EN 350 for durability of specific species.

Pre-finished interior cladding

Interior cladding, or panelling, provides sound and heat insulation and helps maintain a healthier living environment through regulating humidity levels - even in bathrooms.

It is available ready supplied with factory applied finishes and with pre-manufactured fixing clips for easy fitting.

Wainscot effect kits are also available.

For more information, contact Taylor Maxwell at www.tmtgroup.co.uk

Plywood for cladding

Plywood is strong, light and stable. Both spruce and birch plywood are ideal for use in wall construction (for structural use, ensure plywood complies with BS 5268-2:2002). For a decorative finish for interior walls, use top quality birch plywood.

Plywood has good acoustic properties, is highly durable, provides increased rigidity and load-bearing capacity for wall structures, and can be prefinished with stains, varnishes and paints. Remember to always seal bottom edges of sheets in contact with the floor before installation.

Sizes

Standard plywood panel sizes are 1220mm x 2440, 3050 or 3660mm. Standard panel thickness are 4, 6.5, 9, 12, 15, 18, 21, 24, 27 and 30mm. The recommended thickness for wall and ceiling panelling is 12mm.

Fixing methods

Decide if you want concealed joints or features.

Leave an expansion gap between panels to allow for changing moisture levels.

Space supports at 400-600mm centres.

Use wood screws, nails, adhesives or machined profiles, with screw lengths of 2.5 to 3 times the panel thickness.

Leave a fixing distance from the edge of the panel of at least the panel’s thickness.

Nails and screws to be at 150mm centres along the edges and 300mm elsewhere.

Publications

TRADA - External timber cladding guide

Best practice guidance on the choice of timber species and profiles for cladding configuration, detailing and designing for durability. Includes 33 colour photographs whilst drawings cover fixing options and detailing around windows and corners.

Click here to order publication

Learn more from the Timber for exterior cladding module in wood for good’s Online Learning. It’s free to architects, specifiers, members of the TTF and wood for good. To register free click here