TERMINOLOGY
Chalk line: A line made on the roof by snapping a taut string or cord dusted with chalk. Used for alignment purposes.
Dormer: A framed window unit that projects through the sloping plane of a roof.
Eaves: The horizontal, lower edge of a sloped roof.
Fascia: Horizontal trim at the eaves that covers the rafter ends.
Felt: A flexible sheet that is saturated with asphalt and used as an underlayment, sometimes called "tar paper"
Flashing: Pieces of metal or roll roofing used to prevent seepage of water into a building around any intersection or projection in a roof such as vent pipes, chimneys, adjoining walls, dormers and valleys. Galvanized metal flashing should be minimum 26-gauge. There are 4 main types of flashing used in residential roofing systems:
Valley flashing: This flashing is used in open valleys of the roof. Most often leaks are found in the valley flashing's due to flashing that is nailed to tightly to the decking or shingles that are not trimmed far enough off the flashing.
Plumbing vent flashing: Plumbing vent flashing prevents rainwater from running into holes cut for pipes in the roof. This flashing is sold according to the size of the vent pipe and the roof angle. Roofing material is installed over the flashing.
Lead flashing: When working with tile roofs, lead flashing is used. In the case of a plumbing vent flashing, the lead flashing is actually molded to the shape of the tile's surface. Then the top of the lead flashing is covered by the next tile to prevent water from seeping under the flashing.
Step flashing: When a chimney or dormer wall intercepts the slope of the roof, step flashing is used. Step flashing is usually a metal piece that is bent in the middle, so that one end lays on the roof, and the other against the vertical wall of the dormer or chimney.
Flashing is one of the most important elements of the roof because it seals the seams and joints of the roof--the locations where leaks are most likely to occur. Often, flashing is not maintained well, or installed correctly in the first place. Check for the following signs that your flashing needs maintenance or repair:
- Rusting of metal flashing (in the UK we use lead)
- Excess leaves and debris in valleys or seams of the roof (can lead to rusting and corroding of the metal)
- Prolonged exposure to the elements such as moisture, UV rays, climate changes--especially when asphalt compounds or caulking material is used. Look for cracks, loss of elasticity and de-lamination.
In many cases the flashing can be cleaned and then repaired, re-laminated or repainted (even in the case of rust). In other cases, the flashing may need to be replaced.
Flashing cement: An asphalt-based cement used to bond roofing materials. Flashing cement is also known as mastic.
Gable: The upper portion of a sidewall that comes to a triangular point at the ridge of a sloping roof.
Gable roof: A type of roof containing sloping planes of the same pitch on each side of the ridge. A gable roof typically contains a gable at each end.
Gutter: The trough that channels water from the eaves to the downspouts.
Hip: The inclined external angle formed by the intersection of two sloping roof planes. The hip runs from the ridge to the eaves.
Hip roof: A type of roof containing sloping planes of the same pitch on each of four sides. A hip roof contains no gables.
Joists: Any of the small timbers or metal beams ranged parallel from wall to wall in a structure to support a floor or ceiling.
Mansard roof: A type of roof containing two sloping planes of different pitch on each of four sides. The lower plane has a much steeper pitch than the upper, often approaching vertical. Contains no gables.
Mastic: An asphalt-based cement used to bond roofing materials. Also known as flashing cement.
Open valley: Method of valley construction in which shingles on both sides of the valley are trimmed along a chalk line snapped on each side of the valley. Shingles do not extend across the valley. Valley flashing is exposed.
Overhang: That portion of the roof structure that extends beyond the exterior walls of a building.
Pitch: Also known as "slope", pitch is the measure of how "steep" a roof is. For example, if a roof is "4 in 12", the roof rises 4 inches for every horizontal run of 12 inches. The pitch of the roof is a big factor in determining the kinds of materials that can be used and the longevity of the roof. Usually, a steeper roof (higher pitch) will last longer due to its better drainage capabilities.
Plastic cement: A compound used to seal flashing's and in some cases to seal down shingles as well as for other small waterproofing jobs. Where plastic cement is required for sealing down shingles, use a dab about the size of a half dollar unless otherwise specified.
Rafter: The supporting framing member immediately beneath the deck, sloping from the ridge to the wall plate.
Re-roofing: Installing a new roof system on a building that is not new.
Rise: The vertical distance from the eaves line to the ridge.
Run: The horizontal distance from the eaves to a point directly under the ridge. One half the span.
Slope: The degree of roof incline expressed as the ratio of the rise, in inches, to the run, in feet.
Soffit: The finished underside of the eaves.
Soil stack: A vent pipe that penetrates the roof.
Tear off: Removing an existing roof system.
Valley: The internal angle formed by the intersection of two sloping roof planes to provide water runoff.
Vent: Any outlet for air that protrudes through the roof deck such as a pipe or stack. Any device installed on the roof, gable or soffit for the purpose of ventilating the underside of the roof deck.
Link to the complete alphabetical Roof Helper list. http://www.roofhelper.com
