Even a Class A roof can be vulnerable at its edges. You can argue that the roof edge is no longer the roof, but regardless, it is still important to understand, and address, these vulnerabilities. Debris often accumulates in locations where the roof changes slope (for example, where the roof intersects with a wall and in the valley). During wildfires, embers will also collect at these locations, igniting the accumulated vegetative fine fuels (pine needles, leaves, etc.). If the material that your Class A roof intersects with doesn’t provide the same or similar protection, then your
roof is vulnerable. For this reason, it is important to be vigilant about removing debris from your roof.
If ignited, the debris on this roof would expose the underside of the overhanging roof, or the exterior siding. Both of these components are potentially more vulnerable to flame and ember exposure than a Class A asphalt composition shingle roof covering.
Vertical walls adjacent to the roof can accumulate combustible debris, typically leaves and needles. The ignited debris can expose the exterior siding, in this case wood shingles, and potentially the underside of the roof.
Wind-borne debris can accumulate in the ends of this clay tile barrel roof covering. If accessible, birds can also build nests in the space between the roof sheathing and the bottom of the tiles, also providing combustible debris that is easily ignited if embers are driven into this area (under the tiles).
The ends of this clay tile barrel roof were covered by a cut-to-shape metal strip, but it has become disconnected, or was never properly installed. Embers can easliy enter these openings.
