Roof Fire Ratings
If you live in an area that is prone to wildfires, there are probably building ordinances in place dictating the required fire rating for your roof. For the rest of us, this choice is based on our own level of awareness surrounding the issue of fire safety. Not every home absolutely needs the highest rated materials for roofing, but knowing what’s what never hurts.
The Basics
The classifications for roofing range from A (the least likely to catch fire and burn) to C (the least fire retardant). The rating is not always based on just the shingle material. Instead, it may take into consideration the entire roof assembly including the underlayment, insulation, and construction method used. The ratings are determined by exposing a sample roof to fire from an exterior source. This means it doesn’t indicate what will happen to your roof if a fire originates inside your home.
Material Considerations
Cap sheets (roll roofing felt) or fiberglass reinforced gypsum board products may be used to enhance the fire rating of a less retardant shingle material such as cedar shakes. Materials such as metal and slate are non-combustible. 
However, they should still be installed on top of an appropriate underlayment. If a severe fire occurs, even a Class A roof may need to be replaced because of damage. However, it is still a good investment if it keeps your entire house from burning to the ground!
Related posts:
- Whats Under Your Roof?
- Fire Safety for Tile Roofs
- Cedar Shake Roof Considerations
- Faux Roofing Tile Overview
- Investment Grade Roof
Tags: Roofing
