A Guide To Roof Flashings

Roof flashings are installed during the finishing of a new roof. Flashings are the first line of defense against roof leaks and they are installed everywhere there is a chance of heavy water run-off. This may be at the intersection of the outer wall and the roof, at roof valleys and other roof intersections, around chimneys and vent pipes, and skylight perimeters. Aluminum is the material of choice for DIY flashing projects as it is bends easily. Aluminum also doesn’t rust and corrode. Other materials that can be used are plastic, rubber, roofing felt, galvanized steel and copper. Each of these materials has advantages and disadvantages. Cap and base flashings, continuous flashings, drip edge flashings, step flashings and valley flashings are some flashing styles. Different ones may be used at different places and a combination of two or more may also be used together at some fixtures like the chimney. Cap and base flashings are used where different parts of the roof meet at an angle of 90-degrees or more. In right angled joins, the cap stands on the base, which is laid flat. Instead of using a bent metal sheet, two different sheets should be used to make the cap and the base to avoid damage by stretching and contracting cycles that occur with temperatures changes. Caps and bases overlap, and on slopes, sheets of metal are used to make cap flashings that look like steps. These also overlap. Drip edge flashings are used along rakes that are under and eaves that are over the roof. These are present at the edge of roofs and prevent water seepage from these areas. Continuous flashings are present at the junction of vertical walls and sloped roofs. Step flashings are made, as the name suggests, like steps. But these steps are 3-D instead of like cap flashings that form steps. The vertical and horizontal planes of the steps overlap and the bottommost vertical plane is tucked under roof shingles to be secure. It is then either mortared or caulked. These flashings are common around skylights and chimneys. Valley flashings are for V-shaped intersections in the roofs and the flashings themselves are W-shaped. They double as channels along which water flows off the roof besides being waterproofing fixtures. Vent flashings consist of a cone that goes around the vent pipe. The cone is attached to a flange which is secured under the shingles of the roof. Nails made of galvanized steel are the ideal choice for nailing flashings to the roof. The most common problem with flashings that are not tended to regularly is that they come off loose because of rusted nails. Flashings have to be repaired and replaced whenever you’ve noticed that they’ve gone bad. Scott Rodgers is a brilliant writer who has been writering on roofing for a long time now. His skill has given motivation to a host of workers, ranging from Columbia Roofers Need one? click here!) to Greensboro Roofers (Need one? click here!).

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