The building structure had been designed and constructed with a rooftop patio. The builder had used stamped concrete directly over a torch-down membrane. Drainage was poor and membrane attachment around the perimeter of the roof was substandard. The rooftop terrace eventually started leaking into the house. Additionally, high thermal stresses on the roof, created extensive unsightly cracks in the thin concrete.

A roofing contractor removed the concrete and stucco on the parapet walls around the perimeter of the patio. They then installed a new three-layer torch down membrane, this time bringing it up into the walls around the entire perimeter to form a seamless "bathtub" waterproof rooftop surface. Finally the stucco was replaced and brought down to a drip-screed height of 2".

While the roofing demolition and re-construction work was in process, the owner researched better methods for installing stone or tile over a rooftop waterproof membrane . There were two important criteria for the new rooftop outdoor floor surface: (1) rapid drainage and (2) no direct attachment to the torch-down membrane. The rooftop pitch was shallow falling toward roof drains and would require only minor adjustments in places to bring the finished outdoor floor surface to a level finish.

The owners extensive research led him to the PierdeX® Outdoor Floor System®. One significant feature of this system is its large structural dimension; 32"x32". Unlike other rooftop terrace systems that support single tiles on individual pedestals, the PierdeX® system uses a large panel to support multiple tiles, either uniform sizes or random dimensions. Since the owner was not enthusiastic about square tiles for this application, this system opened many more creative choices for surfacing materials and layout patterns. In addition, the structural panel combined with the Ped-Tite® connector, interlocked all underlayment panels together into a continuous floating floor. The owner found this to be an easy method to achieve a uniform and sturdy outdoor floor surface which could still be dismantled in the future if necessary.

The PierdeX® Outdoor Floor System® could have been installed on pedestals, but the lower 2" clearance did not require this. Instead, the owner placed the Ped-Tite® connectors directly on the waterproof membrane and shimmed them as needed in a couple of places using additional scraps of torch-down waterproofing. Cutting and placement of the PierdeX® underlayment panel was simple, although it took some time to properly measure and optimize the panel layout before starting the installation.

Drip irrigation was to be used for potted feature plants. The 1/2"+ clearance between the bottom of the PierdeX® underlayment panel and the waterproofing provided a clear run for 1/4" drip lines directly from a central valve location to each of a dozen future pot placements. The drip lines simply pop up through the open structure of the PierdeX® panel to feed directly into the center of the pots, completely hidden. In addition to hiding all irrigation, it also provided a convenient raceway for low voltage wiring.

The Outdoor Floor was finished with a mixed pattern of 1" gauged travertine. With the paver thickness of the travertine, the owner was able to set the stone tile as a dry-laid placement over a recommended 4-6 oz. construction fabric. And with the uniform flatness of the PierdeX® underlayment panel, installation of the stone was completed efficiently. The results were pleasing; the stone attractive; the waterproofing and drainage are excellent; and the irrigation invisible. Best of all, the owner takes great pride in completing this PierdeX® Outdoor Floor and travertine stone surface as a DIY, hands-on owner installation!

DexSystems was the former entity name for ODF Inc. PierDex is an early production version of elePHOOT®.