When considering turning an underutilized roof deck into an attractive rooftop patio living space, one of the key issues that homeowners consistently face is the current roof top surface. Not only do you need to ensure no damage will occur to the waterproof membrane and potentially cause leaks, but the rooftop deck will invariably slope to multiple drainage points and there may be raised seams on the waterproofing membrane.
If there are no raised seams, one of the simplest ways of creating an appealing roof deck is simply to lay down snap-together deck tiles. These can be laid directly over the top of the existing watertight membrane, although if you are worried about possible damage due to the plastic mesh underside of the tiles, then you could lay down an extra sheet of EPDM over the entire roof deck region, to give extra protection.
However if the roof surface is uneven and you also want the surface to be perfectly level, then interlocking deck tiles will usually not be the best choice. In these circumstances, your best solution is normally to use structural porcelain pavers supported by a pedestal system. Although porcelain pavers have been available in Europe for many years, they are only now becoming more well known in the USA as an excellent roof deck product. Basically they’re a thicker (3/4”) variation of a conventional porcelain tile that are really dense, tough, impervious to water, frost resistant and stain resistant. The most common size is 24″ x 24″ but many other sizes are now available including 8” and 12” wide porcelain planks up to 94” long. These pavers are strong enough to be supported only on each of the corners rather than needing to be laid level in the roof top surface.
At low elevations the pavers are supported with fixed height pedestal supports, which are simply a plastic or rubber material, typically about 6″-7″ in diameter, either a square or round shape and 3/8” to 1/2″ inch high The pads normally have inbuilt tile spacers to simplify installation and ensure accurate spacing and alignment. These pads typically cost between $1.00 and $3.00 each and can be stacked as required to give extra height or used in combination with neoprene rubber spacers for smaller height corrections. This kind of pedestal support is perfect where you don’t require the deck to be raised any more than absolutely crucial perhaps due to restrictions with door thresholds, but essentially just want to raise the pavers off the surface so that they will not rock on undulations, will cope with surface irregularities and can be precisely levelled over slightly sloping surfaces. If the area is large, the slopes are greater than the typical ¼” per ft., and the deck height at any point is higher than about 1 ½”, then adjustable height pedestals are normally used. These are placed directly over the membrane with the wide circular based ensuring no damage to the membrane can occur. These pedestals can easily be adjusted in height by screwing the central column up or down. Estimating the model and height range of pedestals require can be a bit tricky where the surface slopes in multiple directions. Fortunately Archatrak has developed a pedestal paver estimator to vastly simplify this task. You just need to input the required deck height at all perimeter transition points, mark out any drainage points with their depth from the substrate to the deck surface and select what pavers and pedestals you will be using. The software will then estimate the quantity of each type of pedestal you will require along with the quantity of pavers needed