Roof blisters typically occur when the roof loses its adhesion. They usually result in raised areas that look like bubbles on the roof’s surface. These bubbles can later on be filled with air or water and grow larger in size, especially when they are left untreated.
When it comes to pricing, there’s a marked difference between steep-sloped roofs and low-sloped roofs. Professional roofing contractors will often refer to the steepness of the roofing assembly as its pitch. The typical residential roofing pitch is a range between 3/12 to 20/12. The pitch could be steeper than this maximum limit, although this is very rare.