Timber deck pedestal

Frequently asked questions

How many pedestals per m² do you need for a timber deck?

Allow between 3 and 6 pedestals per m². The number depends on three things: the type of deck board, the spacing between joists and the spacing between pedestals under each joist. The larger the deck, the lower the ratio, because edge pedestals count for less in the total.

Figures from the manufacturer Jouplast for a 20 m² deck: with timber boards and joists every 50 cm, 4.1 pedestals/m² with one pedestal every 70 cm and 5 pedestals/m² with one every 50 cm. With composite boards and joists every 40 cm, 4.6 pedestals/m² with one pedestal every 70 cm and 6.1 pedestals/m² with one every 50 cm. At 100 m², these figures drop to 3.4, 4.4, 4.1 and 5.5 pedestals/m² respectively.

Add a 5 to 10% margin for cuts and adjustments. The calculator on each product page does this calculation from your surface area and your installation type.

What spacing between pedestals for a timber deck?

Two distances matter. The first is the joist spacing, measured centre to centre between two joists: generally 50 cm for timber boards and 40 cm for composite boards. Your board manufacturer's recommendation always takes precedence.

The second is the spacing between pedestals under the same joist: 50 to 70 cm. Stick to 50 cm with small-section joists, composite boards or a deck that will carry heavy furniture. Also place a pedestal close to each end of a joist and at every joint between two joists.

Joists must be timber or aluminium, never composite: composite lacks the stiffness needed to span between two pedestals. See our adjustable pedestals for flat ground and our self-levelling pedestals for a sloping base.