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What Is an Adjustable Pedestal? (Deck Pedestal Guide)
If you have ever stood on a perfectly level rooftop terrace and wondered how it stays flat over a sloped, waterproofed roof, the answer is usually an adjustable pedestal. This guide explains what it is, how it works and why specifiers choose it.
Definition
An adjustable pedestal — also called a deck pedestal, raised floor support or paver support — is a height-adjustable support, usually moulded from plastic, that lifts decking joists, tiles or paving slabs off a substrate. By turning a ring, the height changes in small increments (Vitaro uses 15 mm per ring) so the finished surface can be levelled precisely without cutting or shimming.
How it works
The pedestal stands vertically on the roof slab or ground. Its height is set by rotating the body or an adjustment ring; a locking ring then fixes the position. A head on top supports the decking joist, tile coupler or slab. Because the support is a column rather than a solid bed, the space underneath stays open — which is the whole point.
“The void under a pedestal is a service corridor: drains, cables and the waterproof membrane stay visible, ventilated and repairable.”
Main parts
- Base — sits on the substrate; often a wide, stable shape (Vitaro HE uses an octagonal base, 171.5 mm flat-to-flat).
- Stem / body — the height-adjustable column, with a rotary ring for fine adjustment.
- Head — supports joists or slabs; available fixed, or as a self-leveling head that tilts up to 5° to follow slopes.
- Extenders — optional spacer rings (Vitaro: 100 mm / 150 mm) for tall builds.
Materials
Vitaro pedestals are moulded from polypropylene, with the HE Series reinforced by 10% glass fibre. This combination is UV-resistant and stable from −40 °C to +120 °C, so it performs outdoors for years without cracking or creeping.
Why use one?
Compared with a fixed mortar bed or sleeper system, an adjustable pedestal is faster to install, fully re-levelable, and — crucially — non-penetrating, so the roof waterproofing is never pierced. It also improves drainage and ventilation, reducing rot and ponding.
For a product overview, see the Vitaro pedestal series (HE 25–392 mm, B 20–260 mm, F 20–185 mm). For project ideas, visit Applications.
Related reading
- How to choose the right pedestal (height & load)
- Rooftop terrace on pedestals: design & install guide
- Adjustable pedestal FAQ