From the outside, a roof may seem like a simple structure, a protective layer over the top of a house. Yet from the inside, there is actually a lot more to a roof than what is seen from the outside. Residential roofs are actually constructed in many layers, each of which plays an important part. It is because of this more complex structure that roofing maintenance is so important, since a roofing problem is not always as simple as a hole in a shingle. There are many different parts of the roof that can be affected. Proper maintenance is essential in avoiding problems that could end up requiring extensive repairs.
Trusses are the main structure of the roof itself; the framework of the top of the house. Trusses hold up all the other layers of the roof and in some homes, provide a place for insulation to be laid to help keep the home well-heated and cooled.
Decking or Sheathing
Decking or sheathing is the first layer of the roof. It is usually made of plywood or OSB (oriented strand board), although other materials such as reinforced concrete, metal, or polystyrene are sometimes used depending on the type of roof and the building architecture. Decking is affixed on top of the roof trusses and all other layers are laid on top of the decking.
Underlayment is applied to the top of the decking and provides a water barrier to protect decking from any moisture that might occasionally seep past the external layer of the roof. The underlayment is typically made of a heavy, felted paper material that keeps moisture out, yet remains breathable. The underlayment also acts as a sound and wind barrier as well.
The exterior roofing is the shingle or sheet metal layer that is exposed to the elements. Exterior roofing materials vary depending on the type of home, the local climate, and many other factors. The most common roofing material for a residential roof is asphalt shingles; however, wood shingles and shakes, sheet metal, ceramic, clay and cement tiles, and other materials are also used as exterior roofing material. Flat roofs may also use rubber coatings, rolled roofing material, and other materials that are either spread, sprayed, or rolled on and affixed through the underlayment to the decking.
The ridge cap is a layer of shingles or roofing material that covers the ridge on a roof to protect it and start the downward slope along the shingles or sheeting installed beneath it. When applying exterior roofing material, the ridge cap goes on last to make a waterproof cover that lays over the edges of the top shingles to keep the entire roof from getting wet underneath the shingles.
Flashing is a very important roofing element, one of the main areas where roof leaks are noticed. Flashing is made of aluminum or other metal and covers seams and joints in the roof where getting a good seal might be difficult without it. Flashing is used around the base of chimneys, roof vents, pipes, skylights, and anything else that extends through the roof to keep water from leaking through the space cut into the roof.
It should be easy to see that roofing problems, whether just small leaks or something more extensive, are not as simple as they might seem. The best way for homeowners to avoid having to deal with troubles with the roof on their residence is by with required roofing maintenance as well as timely repairs the moment a problem is discovered. Doing so will keep small issues from turning into much greater ones that can end up affecting multiple parts of the roof system!