Ballast stone traps a lot of dirt making patching difficult.
Roof ballast material.
Drawbacks of a ballasted roof system.
Adds a lot of weight to the roof system typically 10 15 pounds per square feet.
Simply put a ballasted roof is easy to install and basically guaranteed maintenance work for a roofer.
Somebody walking on the roof will undoubtedly step on the ballast and put a hole in the membrane.
A ballasted roof means that the roof membrane is not anchored or adhered in any way to the decking material.
Additional benefits of ballast on a flat roof.
Roofs with pavers as ballast can be used as outdoor patios.
Ballast options and flexibility.
Note that roof systems typically include more than one type of material a built up roof for example will typically include the built up membrane itself with or without gravel as well as some kind of insulation and cover board which will vary in thickness from roof to roof.
The gravel in a ballasted roof helps absorb heat preventing the sun from heating the roof materials below and making the roof more energy efficient.
When the concept first came to the u s plenty of roofers scratched their heads and wondered how the roof stayed on without being anchored especially during high winds or storms.
Holes mean roof leaks and roof leaks mean call the roofer.
One of the advantages of using mm6125 in a protected membrane roof assembly pmr is that once the membrane is installed owners and designers can take advantage of various ballast options gravel pavers and garden roof to suit a specific project s needs.
Extremely difficult to find a leak in this system since the membrane is well hidden.
Ballasted flat roofs are a popular choice especially for commercial buildings.