Roof systems and materials generally are divided into generic classifications: low slope and steep slope.
The five most common low-slope or flat roofing systems are:
- Built-up roof (BUR) membranes
- Polymer-modified bitumen sheet membranes
- Thermoplastic membranes (e.g., PVC, TPO)
- Spray polyurethane foam-based (SPF) roof systems
Most low-slope roof membranes have three principle components: weatherproofing layer or layers, reinforcement and surfacing.
- Asphalt shingles – most common and the least expensive roofing material that is easy to install and comes in variety of styles and colors. Shingle roofing typically lasts 30 years to lifetime.
- Slate roofing – long lasting, fireproof and beautiful but can be very expensive and require specialized installation.
- Metal roofing – lightweight, durable, long lasting (at least 50 years), environmentally friendly and energy-efficient roofing material. Can be expensive but it requires low maintenance and can be installed over existing roof.
- Wood shakes and wood shingles – offers natural look and is environmentally friendly, but it can be an expensive roofing material requiring professional installation and regular maintenance.
- Clay tile and concrete tile – easy to maintain, are fire-proof and durable. Tile roofs can be expensive, however, tricky to install or repair and heavy.
Steep-slope roof systems typically are composed of individual pieces or components installed in shingle fashion. Steep-slope roof assemblies typically consist of three primary parts: roof deck, underlayment and roof covering.