Local roofing materials dealers are a mainstay of the building industry in any local community. They work with roofing contractors, residential builders, and home or business owners to supply them with the products they need to complete their roofing projects. These products include both the finishing materials like shingles or wood shakes, but also the materials which go on first, to help make the roof structurally sound and weather-proof. Local roofing materials dealers carry more than shingles. The project begins by preparing the roof for whatever material is going to cover it. When a roofer pulls off old roofing, they can find anything from a perfect roof, to one that needs to be repaired before it is recovered. Local roofing materials dealers sell oriented strand board or plywood which can be used to replace rotted or damaged materials. If the trusses are bad, the local roofing materials dealers can supply these trusses or direct the roofer or homeowner to where these are available. Once the roof is determined to be structurally sound, the roofer will apply roofing paper, often called tar paper, over the sheathing material. It is applied from the edge of the roof toward the peak, with each successive row overlapping the previous row by at least six inches. Local roofing materials dealers will have several options available. Before the roofing material is applied, the roofer will also want to install drip edge at the bottom edge of the roof, to protect the roof from water running off the roof and finding its way up under the shingles. Flashing is also installed anywhere the roof meets an exterior wall of the home, again, to protect the roof from water.