Yes, you can tile a commercial or industrial flat roof, but you must use tiles that are compatible with your existing membrane.
There are two main types of tiles that can be used in conjunction with flat roof membranes:
- Tiles that sit directly on top of the membrane
- Tiles that are elevated on stands above the roof
Both tile types are used when the building owner desires a rooftop deck.
Tiles that sit directly on the roof are made of rubber (or another pliable material) or they are made of concrete.
Rubber tiles should be of a design that is meant for a flat roof. Do not use tile systems like those found in most gyms. Gym tiles are not meant to be used outdoors and they don’t allow water to drain under them. Tiles made for the roof have drainage channels built in to let water pass through. Make sure the tile material are compatible with your roofing membrane. The best way to determine that is to call your roofing manufacturer and confirm with them the compatibility with the tile material. They may even manufacture their own product and your roof warranty may obligate you to use their tiles.
Concrete tiles need a membrane loosely laid on the roof surface before the tiles are installed. This protects the roof from the tile and lets water pass through. Roofing manufacturers recommend the tiles be interlocking to make them more resistant to wind uplift.
There is a company called Bison Innovative Products that make stands to support roof tiles. They sell concrete tiles, wood tiles, and others. The appeal of their system is that it is modular and easy to disassemble in the event of a leak. This system also allows you to create a perfectly flat surface as the stands are adjustable to your roof slope. If you use the first method where the tile sits directly on the roof, the tiles will follow the contours of the roof.
So, yes you can tile over an existing commercial or industrial flat roof, as long as the tiles you choose are compatible with your existing roof membrane. If they are not, you risk premature roof failure. Modular tiles made specifically for flat roof surfaces are best because they contour to the shape of your roof, facilitate drainage, and make roof repairs easier when needed in the future.
Disclaimer: We recommend Bison Innovative Products as a rooftop deck product provider based on our personal experience and research. We have no affiliation with Bison Innovative Products and do not receive any compensation for making this recommendation. We encourage our readers to conduct their own research and exercise their own judgment before making any purchasing decisions.
Jared Van Vranken is Vice President and lead estimator at Flat Roof Solutions in Malvern, PA. Jared has directed the installation, repair, recovery, and replacement of commercial flat roofs for more than a decade at Flat Roof Solutions. He guides clients in selecting the best roofing material for their needs and budget.