What is a paver pedestal?
A paver pedestal (also tile support or slab support) is a plastic or rubber support placed under the corners of paving slabs, for example on a roof terrace, balcony or car park deck. The slabs rest loosely on the pedestals, level and with open joints. Rainwater runs through the joints onto the waterproofing and follows the roof fall to the outlet. In Dutch the component is called a tegeldrager.
Adjustable pedestals can also carry joists or rails on which decking boards or tiles are fixed. A cheap fixed version made of rubber or bitumen is known as a pad or shim pad.
Advantages
- Slabs lie level even when the roof has a fall.
- The roof waterproofing stays accessible for inspection and repair.
- Water does not stand on the slabs and can drain away under the terrace.
Points to watch
- Roof load capacity: slabs, pedestals, people and furniture together form a considerable load. If in doubt, have a structural engineer check that the roof can carry it.
- Firm base: pedestals belong on a hard, stable base such as a concrete roof deck or compression-resistant insulation. On a soft base they sink and the slabs start to rock.
- Protecting the membrane: on bitumen and EPDM, use pedestals with a rubber base or a protection layer.
- Slab thickness and size: loose-laid slabs must be thick and stiff enough to span between supports. Manufacturers state a minimum thickness per format; large slabs often need an extra support in the middle.
- Height: fixed pedestals suffice on an almost flat roof (with shims if needed); adjustable pedestals are needed for larger height differences.
- Joint: pedestals with spacer tabs keep an even open joint, so separate tile spacers are not needed.
- Wind uplift: light slabs or decking can lift in strong wind; fix them to a substructure or add ballast as the manufacturer specifies.
Related terms
- Slope
- Compression-resistant insulation
- Tile spacer
- Terrace
- EPDM
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