Slate2 results in a 40 reduction in the overall weight of a similar traditional slate roof easily meeting the standard structural roof specification of less than six pounds per square foot.
Light weight roof structure.
In some instances either 6 8 or 10 c purlins doubled back to back can be used to as rafters as a substitute to structural steel beams.
The typical roof structure now consists of steel i beam rafters placed approximately 10 feet this varies depending on purlin size and other variables apart with either 4 6 8 or 10 lightweight steel purlins installed horizontally across the rafters.
Lightweight sometimes a flat roof support structure requires a lightweight green roof.
This modern system designed for light weight bearing construction has been tested over several decades and provides the same durability to a traditional 100 year slate roof.