Plan your deck in the UK

Where do you start with a deck?

With four decisions, in this order: the rules, the material, the size and the budget. The pages on this site follow that order.

1. Rules. In England, decking no more than 30 cm above the ground normally needs no planning permission, and Scotland, Wales and Northern Ireland differ. Guarding is expected where the drop is more than 600 mm. See planning permission and balustrades.
2. Material. Treated softwood is cheapest, hardwood costs more, and composite trades a higher price for far less upkeep. Compare timber decking with composite decking.
3. Size. Turn your measurements into boards, joists and fixings with the decking calculator, and pick board lengths that suit your run with the sizes guide.
4. Budget. Installed prices run from about £40 to £220 per m² depending on the material and frame. The cost guide and installation costs break that down.

What kind of decking suits your garden?

Garden decking and patio decking are often the same project: a platform near the house. A patio deck over existing paving still needs a frame or pedestals, because composite makers want airflow and drainage underneath. Ecoscape, for example, says its boards can’t be laid on a flat surface and need at least 25 mm of clearance. The ground guide covers soil, grass and concrete.

Raised decking adds rules. Above 30 cm in England you’re into planning territory, and above 600 mm of drop guarding is expected. Composite Prime recommends a professional installer for decks higher than 600 mm.

Balcony and roof terrace decking is a specialist job. Millboard’s DuoLift pedestal system is listed for roof terraces and ground-level terraces on a solid, stable base, never directly on soil. AliDeck’s aluminium boards carry an A2-s1,d0 fire class, which matters where a project specifies one. A structural check is the owner’s responsibility, not a calculator’s.

What about recycled or ecological decking?

Claims vary, so look for specifics. Ecoscape’s pedestals are 100 percent recycled polypropylene, and Cladco sells recycled plastic joists and a concrete post for supports. Some boards are wood-free, such as Millboard’s resin and mineral composite. We don’t rate products on sustainability, because makers publish different data and we haven’t verified any independent certification.

How much does a deck cost?

BestBuilders’ 2026 supply and build guide gives £80 to £140 per m² for softwood, £140 to £220 for hardwood and £120 to £220 for composite on level ground with a standard frame, with London higher. On those figures a 12 m² deck comes to £960 to £1,680 in softwood and £1,440 to £2,640 in composite. Boards are the smaller part of the bill, which is why the calculator adds frame and fixings.

Where can you buy and who installs it?

Our supplier directory lists UK sellers with what each says it stocks, checked on its own site. We don’t list installers yet.