Roofing Material for Buildings

Plywood Sheathing

• The base of your roof is constructed by nailing boards to the roof trusses. Three common ways this is done are with plywood sheathing, oriented strand-board (OSB) and lath sheathing. Plywood sheathing is usually 7/16-inch thick. OSB consists of thousands of individual strands of wood between 3 and 4 inches long that are coated with resin glue and pressed together. Lath sheathing is narrow strips of wood nailed to the roof trusses. Plywood or OSB sheathing can be used with any type of roof, while lath sheathing is often used for slate or wooden shingles.

Roofing Paper

• The material laid directly over the plywood sheathing is called roofing paper. This is a heavy paper impregnated with tar to help make it more water-resistant. The paper is installed in horizontal strips on the roof, beginning along the bottom edges and working up towards the peak. The paper is attached to the sheathing with staples every 6 inches. When laying roofing paper, it is important to lay the paper flat against the sheathing and overlap the edges by about 4 inches to prevent leaks.

Flashing and Gaskets

• Flashing is metal, often times aluminum, that covers gaps that could potentially allow water to seep through. Flashing is used along the bottom edges of the roof, in valleys where two sides of the roof meet at an angle, and around skylights and chimneys. Gaskets are pieces of molded rubber designed to slide over pipes and roof vents that extend through the roof. A silicone adhesive is applied to the edges of the gasket to help form a watertight seal.

Shingles

• The most visible roofing materials on a completed roof are the shingles, of which there are several types of materials used. Asphalt shingles are a popular type, and consist of wastepaper soaked in asphalt and coated with ceramic granules. This is one of the cheapest materials used in roofing, but it also wears out sooner than other materials. Wooden shingles are favored by some for their rustic look, but are banned in some areas because they pose a fire hazard. The curves and reddish-brown color of ceramic tiles are one of the most recognizable aspects of a Spanish-style home. Slate is a heavy roofing material and a well-built slate roof can last over 100 years. Metal roofing can be created to resemble different types of roofing, such as ceramic tile or asphalt roofing. Metal roofing can last for several decades, and is fire-resistant, which is an advantage in areas that are prone to wildfires.