The roof membrane and insulation layer are installed using mechanical fasteners that secure both layers onto the building. This is a low-cost, effective solution.
First, the insulation layer is attached to the building, then the roof membrane is bonded to the insulation layer using an industrial adhesive. This can be a good solution for low- and steep-sloped roofs.
The roof membrane is held in place using a layer of rock ballasts to hold the rubber sheets in place. It tends to be the most cost-effective solution, given the speed and simplicity of installation.