Over 25 years ago wood shingle roof systems were very common in San Diego. But over time they have been found to be highly flammable and are being replaced at a rapid rate. With new local fire codes, we will no longer find these roofs in existence in the next few years. You’ll notice that when the wood shingles are torn off, there are wood slat boards known as “skip sheeting” underneath. Before the new roofing material is applied, plywood or OSB board is installed on top to lengthen the life of the roof.