Steep Slope


The most common type of sloped roofing in our (San Francisco Bay) area is asphalt composition shingle. A minimum slope of 3:12 (3” rise for every 12” laterally) is usually required for shingle roofing; however there are exceptions.

Typically, composition shingles are an asphalt-based product, bonded to a reinforcing fiberglass mat, with a mineral granular surface. The asphalt provides the waterproofing and the mineral surface protects the shingle from breakdown due to sun exposure. These shingles are produced by various manufacturers with differing warranties and life expectancies. The main factors in the life of the shingle are the amount of asphalt-more is more; and the technology used in bonding the fiberglass mat and applying the mineral surface. Traditionally, manufacturers have supplied their products with limited warranties; 20 year, 30 year, 40, 50 and so on. More recently, limited ‘lifetime’ warranties have become the norm, with our understanding of ‘lifetime’ being as long as you own the house. Sometimes a homeowner is allowed to transfer the warranty to a new owner. Extended or ‘premium’ warranties are also often offered. If manufacturer’s warranties are important to you, we recommend getting full information directly from their website or printed information. Composition shingles have been around for many decades; they are a proven product with an excellent track record, are relatively easy to install, and offer a robust lower-cost roofing option. A correctly installed composition roof will have a
class-A fire rating and will be available in a wide range of shapes, styles and colors.  

LIFE: 25-50 years
COST: $250-$650