No other material in the home takes more direct punishment than the roof. Depending on what part of the country the house is located, the roof can be tormented by torrential rains, hail, ice build-up, heavy snow and merciless sun. This is why no other part of the house is repaired or replaced more often than the roof and this is why there are so many roofing contractors.
Two distinctive types of roofing were introduced by both the Spanish and, as well, the native Americans. The invaders from Spain brought clay tile shingles that were perfect for preventing the heat of the sun from penetrating into the dwelling. It was also good for rain but the expansion and contraction of water in the wintry areas made it a luck-luster material.
Natives in the northwest used overlapping cedar shingles for their lodges and the aboriginal tribes of the northeast accomplished much the same purpose with tree bark from the birch and maple trees. The malleable wood expanded when wet blocking moisture from entering the dwelling.
Modern roofing contractors have an amazing array of roofing products that can block out the worst of nature s blitzes. Metal, slate, wood, asphalt and clay products make roofing a very specialized renovation. The most popular roofing, and the easiest on the pocketbook, is the asphalt roof because the asphalt roof installers do not have to be as specialized as those who put on clay or metal roofs.
Parts of a Roof
- Rafters/Trusses: This is the part that supports the roof. Most new homes have trusses as the supporting structure and these are pre-made in a factory. The series of triangles that make up a truss provide a strong base.
- Deck: This is the material to which the roof is attached. Decking used to be tongue-and-groove boards but this was later changed to plywood sheets and oriented strand board, or OSB, sheets.
- Slope/Pitch: The slope, or pitch, of a roof directly affects the type of roofing material used. A simple way to find this measurement is to measure 12 inches down the roof surface. Place the end of a level on the start point and lift the other end until the bubble is level. At the 12 mark on the roof measure up to the bottom of the level. If it is 6 then the pitch of the roof is 6-12. A 5 inch rise would be a 5-12.
- Drip Edging: A standard D-style edging folds over the fascia and runs 5 under the shingle to prevent moisture from getting under the shingles from the edges. These are available in different lengths and can be pre-colored to match the fascia.
- Fascia: This is a pre-colored piece of aluminum or vinyl that covers the gale edge of the roof and rafter tails. Gutters are usually attached to the fascia.
- Soffits: The soffits protect the eaves underneath the roof edge from the elements and insects. They are perforated to allow ventilation for the underside of the roof. Like fascia, soffits are made from aluminum or vinyl.
- Underlayment: Usually called tar paper or felt, underlayment is a water-resistant material that goes on the decking before the shingles. The rolls are usually bought by weight per 100 square feet and the most common type is 15lb pound felt.
- Ice Shield: Prevents moisture creep from the freeze-thaw cycle.
- Shingle: Shingles are made from asphalt reinforced by fiberglass.
Types of Asphalt Shingle
This type of shingle contains paper, called felt, soaked in asphalt. This is then pressed out into a shingle and then a coat of adhesive petroleum is applied to hold grains of a ceramic material. This coating strengthens the shingle and prevents it from deterioration by sun and the elements. The life of shingle is measured in years and the higher the rating the better the shingle. Organic shingles are heavier than their fiberglass counterparts making them more durable and less likely to fly off during strong winds.
Asbestos ranked as the best base for shingles but because of the health factor surrounding the substance asbestos was replaced by a matt of fiberglass soaked in urea-formaldehyde resin and coated with asphalt adhesive and the granules of ceramic. These shingles are lighter than the organic types, however they tend to tear off in heavy winds.
Also called architectural shingles this type is actually two fiberglass shingles bonded together with resin. This makes them heavier and less likely to be damaged by the elements.
Asphalt Roofing Hazards
Ice Damming: In the winter snow sometimes melts to ice on a roof. This ice then melts and refreezes in a cycle that creeps up under the shingle, and even the felt, material causing leaking in spots. Although this stops when the weather gets warm the process can weaken the roofing materials in that area and may cause the wood underneath to rot. This is why ice shield is used on the edges of the roof.
Sun: Heat and ultraviolet rays can break down the components of a shingle causing the tabs to crack and curl over time.
Rain: Blowing rain can sometimes get underneath the felt and sit. If this persists then mold and rot can occur.
Trees: Depending on the type of tree a mixture of leaf rot and pitch can cause acids which shorten the life of the shingle. The shade can also help mold take hold. The tendrils from the fungus grow slowly into the shingle causing it to break down. Mold and algae rarely form on roofs which get a moderate amount of sunlight.
Moisture: This can come from rain, wind-driven rain, condensation underneath the roof material and from inside the home. Poorly ventilated bathroom and kitchen exhaust can cause moisture to creep between the wood sheets and cause mildew and rot.
Wind: Besides being a destructive force which can pull the shingle tabs loose from the adhesive wind can also blow dirt and moisture up under the shingles and felt causing rot.Posted by: TrustedPros