The term generally refers to structural strength pavers which are laid over some kind of pedestal support (fixed height or adjustable height) which raises the tiles or pavers off the existing surface to create an elevated deck. Generally the reason for using a pedestal paver system is to create a perfectly horizontal deck surface over a substrate which may be uneven, sloping, or where you want to raise the deck level above ductwork, service pipes or electrical cabling, such as on a roof top.
A variety of paving materials can be used with a pedestal paver system although the overriding consideration is naturally that the pavers must have sufficient structural strength for the required application. This includes concrete paving blocks, porcelain pavers or planks, natural stone, wood, bamboo or composite wood, although with composite wood or natural stone, a support grid is normally required as well.
One of the most common applications for pedestal paver systems is for creating perfectly level decks on rooftops over waterproof membranes. In some situations, there may be limitations on the load capacity of the roof, in which case concrete roof deck pavers may be too heavy. Also because of their weight and bulkiness, transporting concrete pavers to an elevated location can often create some issues. For such applications, structural porcelain pavers, with a typical weight of 9lb/sq.ft. for ¾” thick pavers, can be a better alternative.
Where a natural wood deck is preferred, structural Ipe wood pavers supported by pedestals can be a god option. However these days, in many urban locations, there are increasingly stringent fire regulations that need to be taking into account which may restrict the area that can be laid with wood pavers, or in some circumstances, may entirely prohibit the use of such roof pavers. It’s worth noting that with porcelain pavers, not only are they totally fire resistant but they are also completely frostproof so can be used in regions where freeze thaw /cracking may be a problem. And from a maintenance viewpoint, porcelain pavers are almost totally impervious to water and are exceptionally stain resistant. With some of the latest designs and formats of porcelain pavers, the visual difference between natural wood planks and porcelain planks is remarkable small.
Most paver supports are constructed of polypropylene or a similar rigid polymer and typically consist of a wide base, a central screwed column for height adjustment and a flat head with inbuilt paver spacer tabs on which the pavers are laid. To provide quick installation and micro-adjustment of the height, the pedestal decking systems most commonly use a screwjack type of paver support which allow the height to be adjusted by turning the screwed column either up or down. Spacer tabs inserted in the pedestal head ensure accurate spacing of the pavers. These tabs are normally a fixed crosshatch design, but some pedestal systems have the ability to insert individual tabs in different positions on the head which can be useful if the pavers have been cut in triangles rather than the normal square or rectangular format.
Because the pavers are not fixed to the substate and must be installed with as little sideways movement as possible, one of the more important installation requirements is the presence of a perimeter retaining wall or solid parapet around all sides of the roofdeck installation. The gap between the pavers and the wall should normally be no more than about 1/8”, to prevent movement of the pavers. Stainless steel spring clips which are clipped to the pedestal head and generally the best solution to maintaining a small gap yet ensuring the pavers cannot move.
In any elevated paver system, the substrate will normally slope somewhat for drainage and there may also be a requirement for the pavers to be raised off the surface by the smallest amount possible. In such applications, a screwjack type pedestal cannot provide sufficient height adjustment to be of practical use, so the normal procedure is to use stackable, fixed height pedestal supports with minor height adjustments accomplished by the use of thin rubber shims. Fixed height pedestal supports may either be a rubber or plastic material, although rubber is generally preferable because of its superior sound transmission properties and slip resistance. Generally speaking, the height range covered by fixed height pedestals is between 3/8” and 1 ½”, above which adjustable decking supports become more viable.
At the other extreme of deck heights, a pedestal paver system can create a raised deck up to 2 feet or even higher off the existing substrate. In such cases it is common to use guy wires attached to the pedestals to provide extra rigidity of the entire system.
With roofdeck installations and installations over sloping or uneven substrates, it can be important for the head of the pedestal to be maintained in a horizontal plane. Pedestal paver systems have various means of coping with such sloping substrates. One solution is to install a slope compensating device under the base of the pedestal which ensures the pedestal column is maintained in a perfectly vertical orientation perpendicular to the deck surface. Another solution is to place a slope compensating device on the head of the pedestal, which still ensures that the head is perfectly parallel to the deck surface, but in this case the pedestal column will be sloping slightly. And yet a third option as used with the Eterno pedestal paver system, is to have a ‘floating’ head which automatically provides slope compensation without the need to make manual adjustments as with the former two options. Typically, the slope compensation provided is a maximum of 5% although some makers offer a slightly high maximum. In some cases, slope adjusters can be stacked to provide greater compensation.
Concrete pavers are not always precisely consistent in height, which can potentially create a tripping hazard. To overcome this, most pedestal support systems have the ability to add thin rubber or neoprene shims under each segment of the pedestal head to compensate for any slight height differences of the pavers.
Noise transmission from the deck surface to the roof when the pavers are walked on can be an issue in some installations. Consequently some pedestal paver systems have heads with either a fixed, soft neoprene head or else provide add in rubber shims, which not only to provide sound deadening, but provide some additional shock absorption.
Elevated pedestal paver systems provide a convenient, cost-effective and relatively simple method of building a perfectly horizontal deck surface over a sloping substrate, without interfering or damaging existing waterproof membranes, and without requiring the installation of permanent structures, which may not be permitted in such locations. Elevated paver systems permit the easy removal of pavers for maintenance or inspection of service pipes, wiring or waterproof membranes.