Pedestal Paving
Fixed height pedestals, with some capacity for very minor adjustments, are available for landscaping projects, although they are mainly suited to roof gardens or areas of ground requiring an air gap under the slabs. Made from plastic or nylon, they are mainly used with porcelain slabs (see Porcelain Paving) due to their relatively constant thickness, where even floor levelling is required.
The pedestals provide an elevated surface for both interior and exterior applications, and when used with 20mm thick porcelain (which has the strength to support pedestrian weights) offer good rigidity where solid bases are not possible.
An advantage of laying on pedestals, is that the paving is readily and easily removed. Although the joints between the slabs (5mm) is sufficient to allow water to percolate through the gaps, a slight inclination (1:70) may be required to displace water due to surface tension. Other styles of pedestal include fully adjustable units for those laying beds that are less than even, at various heights.
Grade the base (if applicable) to ensure an even surface to reduce the requirement for too many adjustments, using a straight edge and spirit level, loose lay a row of slabs and set out the pedestals at appropriate spacings. Using a string line, position the slabs and begin laying, ensuring that the pedestal is correctly orientated, and continue until the job is complete. Keep a constant eye on the minor adjustments as work progresses to avoid any ‘rocking’ slabs which could cause trip hazards.
As the pedestals are raised, allowing air and water under the paving slabs, they may be used where low or non-existent damp-proof courses are likely to be a problem, although their use may be subject to contention under the requirements of the Building Regulations.
Note: If required to work to British Standards, pedestal paving techniques are not approved.
These pedestal units are fully adjustable to suit levels and falls. Photograph courtesy of Hardy Landscape Supplies Ltd.
