Decking that
does not bounce.
The boards are the part you see. The substructure, the ventilation and the joist centres are the part that decides how long you like it.
Decking is the right answer when the ground is not: a garden that falls away from the house, a level threshold that would need a metre of build-up in stone, or a space where a warm surface underfoot matters more than a hard one. It is also the element most often built badly, because almost everything that determines its life is hidden the moment the boards go down.
A deck is a timber frame carrying a load, and it is built like one. Joists run at centres set by the board being used and the direction it is laid — diagonal boards need tighter centres than square-laid ones, and composite generally needs tighter centres than timber because it is less stiff along its length. Get the spacing wrong and the deck flexes underfoot immediately; get it slightly wrong and it develops a bounce a year later as the boards relax.
The second thing that decides a deck's life is air. Timber and composite both need ventilation underneath and a drainage gap between boards, because a deck that cannot dry out from below stays wet, and wet timber substructure is where rot starts. That means the frame is held clear of the ground on a bearing that is itself protected, not resting in soil, and the perimeter is not sealed solid all the way round.
Materials
- Composite
- No annual oiling, no splinters, no greying. Capped boards resist staining and fading far better than early uncapped composite did.
- Hardwood
- Balau, ipe and similar dense timbers last decades and look better than anything synthetic. They will silver unless oiled, which some people want.
- Substructure
- The part nobody sees and the part that fails. Treated timber joists at proper centres, or an aluminium frame where ground contact and moisture are unavoidable.
- Built-in seating and lighting
- Benches framed into the deck structure free up floor area, and recessed lighting in risers makes steps safe after dark.
How it is built
- Clear and stabiliseGround cleared, weed membrane laid, levels checked against the door threshold.
- FootingsConcrete pads or posts set below ground movement, not timber resting on soil.
- FrameJoists set at the spacing the board actually requires — composite needs closer centres than timber, and boards bounce when it is ignored.
- Fall and fixingA slight fall away from the house, boards fixed with the correct expansion gap so they do not buckle in summer.
- TrimFascias, step nosings and edge detail — where a deck looks built rather than assembled.
What decides the specification
The things that change the answer on a London job — and that nobody can judge from a brochure.
Composite or hardwood
Composite does not need annual oiling, does not splinter and holds its colour; it moves more with temperature and needs correct expansion gaps, and it can get warm in full south-facing sun. Hardwood weathers to silver-grey unless it is oiled, is stiffer underfoot, and can be sanded back. The choice is genuinely about maintenance appetite rather than quality.
Substructure and ground contact
The frame carries everything. It sits on a bearing clear of the soil, is treated to a grade appropriate for its use, and is ventilated so it can dry. Timber laid straight onto earth, or a frame boxed in solid at the perimeter, is the standard route to a deck that is soft in five years.
Height, and when it needs permission
A deck is normally permitted development while its surface stays no more than 300mm above ground level and it does not, with other garden buildings, cover more than half the garden. Above that height it needs planning permission, and raised decking near a boundary raises overlooking objections — the most common reason a retrospective application is refused.
The threshold detail
Decking is often used to run flush with an interior floor. The finished surface must still stay clear of the damp-proof course, so the detail is a ventilated gap and a drainage channel at the door, not boards butted to the brickwork.
Slip resistance in shade
A north-facing or tree-shaded London deck grows a biofilm regardless of material. Grooved or textured boards help, but position matters more: the wettest, shadiest corner of a garden is where a deck will be most work, and sometimes the right answer is not to deck it.
What goes underneath
A deck is a lid. Anything below it — drainage runs, inspection chambers, a rodding eye — has to stay accessible, which means a removable panel designed in from the start rather than a section cut out later.
What it costs
Every garden is priced from its own survey, because the cost is decided by things that are invisible until the ground is opened: how far the spoil has to be carried, what the existing sub-base is made of, whether levels have to be built up or cut away, and how the site drains. We quote after measuring, not before.
Book a free site surveyDecking & Seating, answered.
Is composite decking better than wood?
Neither is better outright. Composite removes the annual oiling, does not splinter and keeps its colour, which is why most London gardens now choose it. Hardwood is stiffer underfoot, can be sanded and re-oiled back to new, and ages to a silver-grey many people prefer. The honest question is how much maintenance you will actually do.
Do I need planning permission for decking?
Usually not, provided the decking surface is no more than 300mm above ground level and the total of decking and outbuildings covers no more than half the garden. A raised deck above that height needs permission, and it is assessed partly on whether it overlooks neighbouring gardens. Conservation areas and listed buildings have tighter limits.
How long does decking last?
It depends almost entirely on the substructure and the ventilation rather than the boards. Composite boards themselves are long-lived, and quality hardwood is too. Decks fail from below, where an unventilated or ground-contact frame rots out while the surface still looks sound.
Can decking be laid on soil or grass?
Not directly. The frame has to be supported clear of the ground on a stable, drained bearing, with air able to move underneath. Timber sitting on soil holds moisture against itself permanently, and that is the fastest possible route to a soft, unsafe deck.
Why does my deck feel bouncy?
Almost always joist centres that are too wide for the board being used, or a frame that has lost bearing because a support has settled or rotted. Diagonal board layouts and composite boards both need closer centres than square-laid timber, and a deck built to generic spacing will flex.
Decking & Seating across all 32 boroughs.
The rest of what we build.
Tell us about your garden.
A free site survey, measured levels and a written quote. We bring material samples to your door.