IT’S not as fashionable as it once was, thanks to overkill on television home improvement shows. But having a deck is still amazingly popular. No wonder; decks cover a multitude of sins, including a bald lawn and cracked paving.
PLAN FIRST, DIG LATER
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Before you start sawing, sit down with graph paper and a pencil and plan your deck. Then mark it out with pegs and string, and clear the debris. Level and compact the ground, leaving a gentle slope towards the outside edge to help drainage. Lay a secure weed-proof membrane. If you are putting the deck directly on to compacted soil, you should insert concrete flags as “pads” to rest the joists of the deck frame. Dig a shallow square underneath each flag and fill with quick-mix concrete. Check with a spirit level that the flags are level.
GET INTO THE RIGHT FRAME
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Before you nail anything, do a dummy run. The principle of a deck construction is a frame with deck boards laid across it. You can buy pre-formed frames. But to construct your own, take a piece of treated timber, cut to length, and secure it to an outside wall with expansion bolts. This will form the first joist. Deck boards lie at right angles across the framework of joists, so think first about which way you want the boards to run . Continue building a frame with lengths of timber. Nail it together first, check it is square and level, then screw for extra strength, and treat with a wood preservative. It is sensible to space joists about 50-75cm apart. To avoid “bounce”, add extra joists at pressure points.
THE EASY BIT
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Laying the decking is simple. Each board should be fixed across the frame with galvanised or stainless steel screws. Pre-drill holes to prevent splitting and ensure that the screwheads do not protrude on the deck. Cut each board slightly longer than the frame to create an overhang for drainage, and leave a gap of 6-8mm between each board for the same reason. You might like to create a fascia with spare boards to hide the timber frame.
TO PAINT OR NOT TO PAINT?
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Do you want the deck to have a silvery, natural finish, or prefer to paint/stain/varnish? Whatever you decide, a protective sealant such as Seasonite (about £11 a litre) is a good idea; it will protect the wood from moisture and help to prevent splits, cracks and warping. For paint/stain/varnish, Sadolin is the professionals’ favourite: Sadolin Classic Exterior Woodstain costs £21.48 for 2.5 litres (one litre should cover 8-10 sq m), and comes in a wide range of colours.
ALL HANDS ON DECK
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Algae? Chipped and flaking paint? Your deck’s got that tired look. It’s time to scrub it with a stiff brush and a special deck-cleaning and wood-restoring product such as Net-trol, about £12 a litre. Use a pressure washer with care; its force can rip up fibres in low-quality wood.
WEB WATCH
www.tda.org.uk — the Timber Decking Association is dedicated to information on laying a deck.
www.thisoldhouse.com — American DIY website with pages dedicated to the art of building and maintaining a deck.
www.fsc-uk.org — guidance on buying decking from a sustainable timber source.