Most commercial roofing systems, whether flat or low-sloping, consist of multiple layers of material, each layer playing a special role in the system. Any roof is composed of the topmost, covering surface, openings, such as roof windows and chimneys, draining and ventilation, but here are some details about the components of the different systems used on commercial buildings:
- Built-up roofs – also called tar and gravel roofs, these systems are composed of alternating layers of tar on special fabric for reinforcement and ballast or gravel. Many of these roofs are made up from four or more layers;
- Single-ply membranes – these systems are made from factory-manufactured membranes that are 30-60 millimeter thick and are fully adhered and held down to the underlayment with ballast;
- Spray foam roofs – these roofs use polyurethane foam that is sprayed on, then a surface coating is applied for protecting the foam from the harmful action of water and solar radiation.;
- Metal roofs – the most common type of commercial roofing uses metal panels, usually made from galvanized or stainless steel, installed over a layer of roof felt or other underlayment installed on the roof deck. Metal roofs can also be installed on top of an existing roof, without requiring the building owner to have the old roof removed. Have the professional commercial roofing contractors out to inspect and repair damages, or provide an estimate for a roof replacement.