Tembok Carpenter & Building Services
Decking design and installation
Good decking starts below the boards. The frame, the ground beneath it and the way water leaves the surface decide how long a deck stays level and safe, so those are settled before choosing a board colour.
Decide what the deck is for
A deck outside the kitchen used for dining needs a different size and shape from a raised platform at the end of the garden. Start with the furniture you want to put on it, the route from the back door and where the sun falls at the times you use the garden. A small deck that is easy to reach often gets more use than a large one that feels separate from the house. Mark the outline on the ground and live with it for a few days before fixing the dimensions.
Height is the next decision. A deck close to ground level is simpler to build and usually needs no guarding, while a raised deck on a sloping plot needs posts, bracing and a balustrade, and may bring overlooking into question. Where a deck sits next to the house, keep the surface below the damp-proof course and leave air vents clear. If the plan involves a raised platform or a change close to a boundary, check the planning position before ordering materials.
What a decking installation involves
The work usually begins with clearing and levelling the area and laying a weed-suppressing membrane. Posts or pads are then set to carry the joists, and the sub-frame is built level with a slight fall so rainwater runs off the boards rather than sitting on them. Joist spacing is chosen to suit the board being used, because composite and timber boards span differently. Fixings matter too: screws designed for external use hold better and cause fewer problems than nails as the timber moves through the seasons.
Ventilation under the deck is often overlooked. Boards need gaps between them and air needs to move beneath the frame so it can dry after rain. A deck boxed in tightly at the edges stays damp, which shortens the life of timber and encourages algae on the surface. Steps, fascia boards and edging are fitted last, along with any balustrade, so that heights and finishes line up with the doorway and the lawn.
Timber or composite boards
Softwood decking is treated against rot and is the most common choice, while hardwoods offer density and a different appearance. Both weather over time and benefit from cleaning and occasional treatment. Composite boards combine wood fibre and plastic, need less routine finishing and come in a range of colours, but they are installed to the manufacturer’s instructions on the frame spacing and expansion gaps. Ask to see samples outside rather than under shop lighting.
Grip and maintenance are worth comparing as well as looks. Shaded decks under trees can become slippery, so a grooved or textured surface and regular cleaning help. Plan any lighting or power before the boards go down so cables can be routed safely, with electrical work carried out by a suitably qualified trade. Tembok offers a free site visit to look at the levels, the ground and access, followed by a written quote that sets out the frame, boards and finishing details.
Decking — frequently asked
Do I need planning permission for decking?
Many low garden decks fall within permitted development, but decking more than 30 centimetres above the ground needs planning permission, and a deck at a listed building or flat may need permission too. Check the position for your property before building.
Can decking be laid straight onto soil?
It is better to build a proper sub-frame on posts or pads with a membrane beneath. Boards or joists left in contact with wet ground stay damp and deteriorate sooner.
How do I stop decking becoming slippery?
Allow a slight fall for water to run off, leave ventilation gaps, choose a textured board where the deck is shaded and clean it regularly to remove algae and leaf debris.
Can an old deck be re-boarded instead of replaced?
Sometimes. If the sub-frame is sound, level and well fixed, new boards may be laid over it. Rotten joists or posts need replacing first, which is checked at the site visit.
Useful reading
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