Common Roofing Terms & Parts You Need to Know
Whether you’re in the market for a new roof and you’re starting your due diligence or you just need simple repairs, here is a handy list of terms and components that you will find helpful (especially if you are trying to interpret insurance paperwork and estimates provided by your contractor.)
COMMON ROOFING TERMS:
Square – In roofing terms, a ‘square’ is equal to 100 square feet and is the measurement used to determine how many bundles of shingles will be used for the roof. Each bundle typically covers 33 1/3 square feet, plus an additional 10 percent is added to account for trimming and waste. As an example, a 40 square job would call for 132 bundles of shingles, including the 10 percent for the trimming allowance.
Pitch, Slope, Rise and Run – Pitch is used to describe the slope, or how steep a roof is. The measurement, in inches, that the roof rises (‘Rise’) vertically for every 12 inches it extends horizontally (‘Run’). You can see this indicated as, for example, 7/12 or 7:12. This ratio simply means that for every 12 inches of run the roof rises 7 inches in pitch. It should be noted that there are only two types of roofs, sloped or flat. A flat or low sloping roof would be in the range of 2/12 – 4/12, conventional roofs are typically in the 5/12 to 9/12 range and anything over a 9/12 is considered a steep roof. Keep in mind that the slope will impact the maintenance required, materials used and the cost of the project.
Algae – Rooftop fungus that can leave dark stains or streaking on roofing
TYPICAL PARTS OF A ROOF: Below you will find the major roof components illustrated and briefly defined.
Dormer – the structure (walls and roof) around a window that projects from a sloped roof.
Roof Truss – the skeleton of the roof. A framework of beams that support the roof.
Rafters – The beams that run from the top of the roof to the bottom. Part of the roof truss.
Decking or Sheathing – Panels that cover the rafters and to which the roofing material (shingles, metal panels, etc..) are attached. This can also be referred to as the ‘Deck’ or simply OSB, the industry name for the plywood used.
Underlayment – often called tar paper this heavy felt paper (synthetic materials are available as well) is placed on top of the decking before the roofing material is installed to offer an additional layer of protection from moisture.
Drip Edge – edging that is placed at the end of the roof (end of the eaves) used to allow water to run-off and drip clear of underlying construction. While this is not a code requirement in all areas, you should check with your local municipality for codes in your location. Also check your insurance policy, some policies will not pay for a code upgrade on a reroof even a claim is being paid.
Fascia – trim used to cover the rafter end of the eaves. Often where gutters are attached to the house.
Soffit – a finished underside of the eaves. Covers the area between the end of the eaves and the house.
Valley – internal angle formed when by the intersection of two sloping roof planes. The intersection of a cross hip or cross gable roof.
Hip – external angle formed by the intersection of two sloping roof planes.
Gable – triangle shaped part of the end of a building underneath the roof and above the main portion of the house.
Ridge – the highest point of the roof that runs the length of the roof.
Ridge Vent – a hard plastic strip installed to allow for optimum air flow and ventilation.
Flashing – Pieces of metal used to prevent the seepage of water around any intersection or projection in a roof, such as vent pipes, chimneys, valleys, and the joints at vertical walls.
Starter Strip – Asphalt roofing applied at the eaves that provides protection by filling in the spaces under the cutouts and joints of the first course of shingles.
