Decking ideas

Which layouts can you choose?

A straight run is simplest. The others cost more in material and framing, and makers give specific rules.

Cladco’s PVC guidance, from a search extract, says diagonal designs need joists no more than 250 mm apart, although its Nordeck page gives only 300 mm. EnviroBuild’s design guide says standard centres of about 300 to 400 mm tighten to roughly 250 to 300 mm for diagonal layouts. Allow extra for waste: the board calculator lets you set it.

How do you add levels?

By varying the joist height or using adjustable pedestals, according to EnviroBuild. Millboard’s DuoLift goes from 15 mm to 350 mm combined. For multi-level decks, plan the steps early; see decking steps.

What about lighting, planters and hot tubs?

Plan lighting before the boards go down, with cabling routed while the joists are going in. One DIYer who built over an uneven slab ran cables for lights before laying boards because fitting them afterwards is awkward. A hot tub weighs 1,500 to 2,500 kg with water and people, so it needs a separate support. EnviroBuild gives no weight for planters. Ecoscape says to reduce joist centres for hot tubs or heavy furniture.

What do raised and balcony decks need?

Raised decks bring rules. In England, decking above 30 cm normally needs planning permission, and guarding is expected above a 600 mm drop; see planning permission and balustrades.

Balconies and roof terraces are more demanding. EnviroBuild’s July 2026 article says that, for new work from 1 December 2022, balconies on residential buildings with a storey 11 m or more above ground must use Class A1 or A2-s1,d0 materials, and that most wood-plastic composite tests Euroclass B, C or D, below that. Below 11 m, timber and composite typically comply. AliDeck’s aluminium board is rated A2-s1,d0, and Eva-Last’s Apex has a Bfl-s1 class for its single-cap profile. Millboard shows its Plas-Pro recycled plastic subframe for low-height roof terraces, and DuoLift pedestals for concrete, paving or a roof membrane; it gives no load rating or fire class for them. Whoever is responsible for the building has to check the structure.

Which colours and boards suit a design?

See the colours guide and decking boards. For the frame behind any layout, start with the frame guide.