Joist Support Riser Pedestals

Your joist pedestals must be installed on a prepared raw surface or a concrete slab. We strongly advise against installing them directly on bare soil without stabilization, due to the risk of ground settling or shifting caused by weather conditions (rain, drought) or the weight of the structure. Whether you place your pedestals on a raw surface or a concrete slab, the base must be clean, stable, and well-leveled to ensure the long-term durability of your deck.

The spacing between pedestals depends on the type of wood and the size of the joists you are using. As a general rule, we recommend a distance of 70 cm between each adjustable pedestal. For the joists, we suggest a center-to-center spacing of 50 cm if your decking is made of natural wood boards. Please note that these guidelines differ for composite decking.

Jouplast® pedestals have a crush resistance of over 1 ton. However, the weight a wooden deck on pedestals can support doesn’t depend solely on the pedestals’ strength—it also depends on the type of wood used for the decking. We therefore recommend consulting your wood supplier for more precise information.

More generally, if you plan to place a heavy item on your pedestal deck, such as a hot tub, we suggest using our PROFILDECK® solution (aluminum joists), which allows for better weight distribution across the structure of your pedestal-mounted wooden deck.