Myth #2 – All asphalt shingles are basically the same.
Today’s laminated and fiberglass-reinforced products are better than ever. Shingles are rated for durability; some are warranted to last 50 years and guarantee wind resistance (up to 110 mph). Manufacturers offer limited lifetime warranties. Some shingles are made to combat specific problems. For example, in humid areas, some roofs, over time, show a black mold. Algae-resistant shingles contain embedded granules of zinc and copper, which, when mixed with roof water, are natural algaecides. Other shingles are manufactured to look like wood shakes or slate tiles.
Myth #3: Flashing needs to be replaced only when a new roof is being installed.
Flashing, the metal material fabricated to divert water away from vents, pipes and other roof openings, including chimneys, is its own, separate animal. It can lay in place for years and can protect even longer than other components of the roof. Or it can fail in months and otherwise ruin a perfectly sound roofing installation. As a rule, flashing should be checked every six months. A visual inspection can be made with binoculars. Look for dried caulking or sealant, cracked or broken flashing pieces and damaged shingles in contact with the flashing. If a visual inspection turns up potential problems, have a roofing contractor climb the ladder for a better look or to make repairs.
Myth #4 – Attic insulation saves energy and helps roof performance.
Adding more than the required insulation can block ventilation openings at the soffits and eaves and might trap moisture. Trapped moisture can warp and rot sheathing from the attic interior and also can be a source for mold. Actually, there is a special relationship between insulation and ventilation. Insulation is rated by thermal resistance, called R-value, which indicates the resistance to heat flow. The higher the R-value, the greater the insulating effectiveness. Determining existing R-value is based on the type of insulation material and its thickness. Increasing the R-value with another layer of fiberglass would seem to be logical. However, adding insulation can vary the temperature at the wall, possibly creating condensation inside the attic. Proper ventilation eliminates moisture buildup and maintains steady attic temperatures, in both cold and warm seasons. Ventilation devices, including fans, vents, louvers and ridge venting, are rated in square inches for net free area (NFA). Signs of inadequate ventilation are ice-damming, mold on the underside of the sheathing and excessive frost accumulation on the roof deck or in the attic.