Glossary of Roofing Terms

Roofing contractors talk about decking, flashing, valleys, and slope — and if you're not in the industry, it can feel like a foreign language. At Roofs Over Texas, we believe an informed customer makes the best decisions. This glossary is here to help.

  • A premium asphalt shingle with a dimensional, layered appearance. More durable and attractive than standard 3-tab shingles. Also called laminated or dimensional shingles.

  • The most common roofing material in the US. Made from fiberglass or organic felt saturated with asphalt and coated with mineral granules.

  • The system of vents that allows air to circulate through your attic — reducing heat buildup, preventing moisture damage, and extending shingle life.

  • A traditional flat roofing system made of alternating layers of bitumen and reinforcing fabric, topped with aggregate. Known for its durability on commercial buildings.

  • The wooden boards (usually OSB or plywood) that form the structural base of your roof, onto which all other roofing materials are attached.

  • A roofed structure projecting from the main roof — typically containing a window. Common in residential construction.

  • A metal strip installed at the roof's edge to direct water away from the fascia and into the gutters. Required by most building codes.

  • Ethylene Propylene Diene Monomer — a durable rubber membrane commonly used on flat commercial roofs. Known for its longevity and low maintenance.

  • The board running along the lower edge of the roof that the gutters attach to. Protects the rafter ends from weather exposure.

  • Thin pieces of metal (usually aluminum or steel) installed at transitions and penetrations — around chimneys, skylights, vents, and valleys — to prevent water intrusion.

  • The mineral particles embedded in the surface of asphalt shingles. They protect the asphalt from UV damage and add fire resistance. Granule loss is an indicator of aging or hail damage.

  • A roof where all sides slope downward to the walls. Hip roofs are common in Texas and are generally more wind-resistant than gable roofs.

  • A self-adhesive waterproof membrane installed under shingles at vulnerable areas — eaves, valleys, and penetrations — to prevent leaks from ice dams and wind-driven rain.

  • Class 4 shingles rated for superior resistance to hail damage. Often qualify homeowners for insurance discounts in Texas.

  • A roof with a pitch of less than 3:12. Most commercial buildings have low-slope roofs, which require different materials than steep-slope residential roofs.

  • A commercial roofing membrane made from asphalt modified with polymers for improved flexibility and durability. Ideal for flat or low-slope applications.

  • The angle or steepness of a roof, expressed as a ratio (e.g., 4:12 means the roof rises 4 inches for every 12 inches of horizontal distance).

  • The rubber or metal collar that seals around plumbing pipes where they penetrate the roof. One of the most common sources of roof leaks when it deteriorates.

  • Water that remains on a flat roof more than 48 hours after rainfall. A sign of improper drainage that accelerates roof deterioration.

  • The sloped edges of a gable roof — the sides that are not the eaves. Properly sealed rakes prevent wind-driven rain penetration.

  • The highest horizontal point of a roof where two slopes meet. The ridge cap covers this area and is a common point of failure if not properly installed.

  • A continuous vent running the length of the ridge that allows hot air to escape the attic. Works in conjunction with soffit vents for optimal airflow.

  • The underside of the roof overhang, between the fascia board and the exterior wall. Soffit vents allow cool air to enter the attic.

  • A metal roofing system where the panels connect at raised seams rather than exposed fasteners. One of the most durable and weather-tight roofing systems available.

  • Thermoplastic Polyolefin — a heat-reflective single-ply membrane widely used on commercial flat roofs. Known for energy efficiency and resistance to UV and chemical exposure.

  • A layer of felt or synthetic material installed directly on the roof deck before shingles. Acts as a secondary barrier against moisture.

  • The V-shaped channel formed where two roof slopes meet. Valleys channel large volumes of water and are a common location for leaks if not properly flashed.