The weight of roofing constructions above the truss rafter may be estimated with the calculator below.
Stone ballast roof weight.
Drawbacks of a ballasted roof system.
Despite the positive qualities associated with a ballasted roof system there are some challenges.
A ballasted roof generally refers to a single ply roof membrane that is held in place against wind uplift by loading the surface with either stone ballast or pavers.
Epdm roof membrane 60 mil fully adhered membrane only 0 47 lbs.
1075 2000 lbs.
This study showed that when the ballast weight is a minimum of 15 psf or greater the ballasted system stone or paver performs the same or better than the energy star listed tpo product.
Epdm roof membrane 90 mil fully adhered membrane only 0 56 lbs.
Adds a lot of weight to the roof system typically 10 15 pounds per square feet.
It can also be a bit challenging to find a leak with a ballasted roof system and because the stones tend to collect a lot of dirt patching it can be a bit difficult.
The weight on a ballasted roof can be from 10 to 25 pounds per square foot meaning the substructure must be designed specifically to carry more weight than other roofing systems.
The amount of ballast varies from 50 to 65 kg m 10 to 13 psf in conventionally loose laid gravel stone ballasted single ply assemblies.
Ballast stone traps a lot of dirt making patching difficult.
The membrane for such systems is usually not attached to the substrate although some systems do have supplementary perimeter attachment.
Epdm roof membrane 60 mil ballasted membrane and stone ballast only 10 75 20 lbs.
Since nothing secures the waterproofing membrane to the roofing materials underneath ballast is needed for weight to protect the roof from strong winds.
Ballast is assumed to be round 38 mm 1 5 in or 64 mm 2 4 in smooth stone consisting of ballast gradation sizes 2 and 4 as specified in american society for testing and materials astm d448.
This study showed that when the ballast weight is a minimum of 15 psf or greater the ballasted system stone or paver performs the same or better than the energy star listed tpo product.
It is very important to note that the amount of gravel being applied to a roof must be precise it depends on the specific roofing spec being used and the building type.
This study was presented to epa and a submittal was made to have this cool ballasted system listed as a qualified energy star roof product.
Too much gravel can result in a structural issue due to weight.
Ballast is different from bur protective gravel.
52 5 97 65 kg.
This study was presented to epa and a submittal was made to have this cool ballasted system listed as a qualified energy star roof product.
Ballast stones are usually one to two inches thick and applied more generously than on a built up roof.
Since the ballast is the primary.
