Exterior tile installations are exploding, with consumers, architects, and landscape architects choosing interiors that flow to exterior patios and lanais, and roof decks outfitted with 2 cm gauged porcelain tile pavers. Pedestal installation systems have helped to expand the opportunities for gauged porcelain tile pavers to beautify outdoor settings. These unbonded tile systems offer level walking surfaces, superior water management properties, and less chance of freeze/thaw damage and efflorescence.
But only if they are installed correctly.
To provide essential education about these pedestal system installations, a white paper titled “Gauged Porcelain Pavers on Pedestals,” and a “Problem/Cause/Cure (PCC)” chart were added to the most recent 2024/2025 NTCA Reference Manual, on pages 248-251. Every NTCA member receives one of these publications as part of their membership, and PDF copies can be purchased at NTCA’s online story at https://www.tile-assn.com/store/.
Woody Sanders of D.W. Sanders Tile & Stone Contracting, in Marietta Ga., headed up an NTCA Technical Committee subcommittee to study and assess paver-on-pedestal installations. Schluter’s Shon Parker and Khali Pharand assisted, as did Lambert Tile & Stone’s Dan Lambert. Schluter’s Joseph Mattice added invaluable edits on the last round before publication.
The main goal was to develop a white paper, Sanders said, and the PCC chart “came along for the ride.” Though an A137.3 standard exists for the manufacture of the paver itself, there are no standards established yet for this installation system. The absence of an installation standard can cause confusion in the market, especially the more widely it is used.
For instance, Sanders said, though 2 cm pavers are porcelain tile and can be set in a thinset application just like any tile, they have very specific working characteristics, and some serious limitations.
“In many places hardscape contractors are taking on this work and having many problems,” Sanders said. “No one knows what category to place this into. The tile contractor… is best suited for these applications.
“While pedestals are not new, porcelain pavers on pedestals are,” he added. “And educating the Technical Committee and their continual input and questioning was a big part of all this.”
Sanders said it is such a complex topic that it took the Technical Committee six meetings before it would give approval.
As Sanders was developing the white paper, he simultaneously developed the PCC chart to outline the many failures where his assistance or consultation had been requested, or had been discussed with various people in the industry.
“I wanted to get ahead of this,” he said. “I have been deep in this now for seven years and it has been a task navigating a lot of dialog and information from the paver manufacturer and the pedestal manufacturer.”
Sanders pointed out two essential aspects of paver-on-pedestal installations:
- In almost every case, the paver needs to have a reinforcement.
- You must have containment. Sanders said that implosion is the greatest concern in paver-on-pedestal installations.
Concerning implosion, this is where the tile does not just crack but implodes – collapses violently inward – and “someone will get hurt,” Sanders said. It creates HUGE liabilities. This can happen at a bar on a hotel deck, from outdoor furniture that is designed to be heavy so it doesn’t blow away and even the weight of people themselves. “You do not want them going through the tile,” he said.
White paper overview
A short overview of what the white paper covers includes:
- What a pedestal system is
- The components of the system including the gauged tile paver
- The use of a backing layer to prevent implosion and to provide lockdown taps to handle wind equalization or uplift
- The pedestal itself
- Universal requirements for the installation such as:
- containment or abutting a wall curb or some type of restraint and being supported at the edge
- minimum compressive strength of the substrate
- the use of a slip sheet between the pedestal base and waterproofing membrane
- take-offs in multiple dimensions, depending on drain location, slope and in how many directions the roof slopes
- using wet saw blades specifically designed for cutting porcelain pavers
- instruction on routine maintenance and care including being on the lookout for rocking pavers and adjusting them to eliminate tripping hazard.
Problem/Cause/Cure document
The Pavers on Pedestals Problem/Cause/Cure chart presents five situations that can arise, with detailed information at their corresponding causes and what to do about them. The problems are:
- Tile imploded
- Paver shifting off pedestal
- Tile breaking at pedestal head
- Paver joint opening and closing
- Paver uneven from tile to adjacent tile
Sanders summed up: “We know the industry is slow to adopt language that makes any affirmative statements. I believe there is an opportunity here for our members. What NTCA Technical Committee does – and can do because of the way it is structured – is get vetted information into the industry’s hands quicker than anyone else.
“This white paper and PCC [chart] are the first written documents of their type in the industry,” he concluded. “I hope that one might be able to use both documents to start having informed conversations and take the right steps.”
Lesley Goddin has been writing and journaling since her first diary at age 11. Her journey has taken her through a career in publishing and publicity, landing her the editor position of TileLetter and its special publications in 2006. Her goal is to educate, inspire, recognize and encourage those in the tile industry -- especially the tile and stone contractor.
