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Ballasted System

Firestone TPO Ballasted System


The Firestone TPO Ballasted System is an economical TPO Roofing System, suitable for a wide variety of buildings. It can be applied on any building that can accommodate the extra load of the ballast and where the roof slope does not exceed 10%.


  • Low installation cost
  • Use of large TPO panels up to 3.05 m
  • Fewer seams
  • Fast installation
  • Large choice of compatible substrates
  • Excellent fire rating
  • Superb weathering resistance


TPO sheets are loose laid over an acceptable substrate. Adjoining sheets are overlapped a minimum of 75 mm and the seams are heat-welded to form a continuous watertight membrane. Once the seams are welded and roof perimeters and penetrations are flashed in accordance with Firestone specifications (PDF), the TPO membrane is held in place using the following materials as ballast (with a minimum weight of 50 kg/m²):

  • Gravel in form of round, smooth, river washed aggregate without broken pieces, of adequate size (nominal 16 to 32 mm).
  • Concrete pavers with smooth trowel finish (min. 50 mm thickness).
  • Crushed gravel that must be graduated.
  • Poured in-situ concrete.

Prior to selection of this system, the specifier should evaluate structural conditions of the building to verify its load bearing capacity. Roof slopes and wind requirements should also be investigated.