19 Essential Roofing Terms and What They Mean

One "square" is a 10 foot by 10 foot section of your roof equal to 100 square feet. A 20-square roof, for example, has 2000 square feet of surface area.

A facet is a single surface of your roof. Roofs are made out of many facets that sit at a slope. The more complex your roof is, the more facets it has. Sometimes a facet is referred to as a slope.

Pitch refers to how steep a roof is. An 8:12 pitch means the roof rises 8 feet for every 12 feet of length.

Two facets of a roof meeting at an inward angle, creating a V shape.

Flashing is a thin metal material that directs water away from certain areas of your roof like chimneys and valleys. Most leaks form near these areas so flashing is an extra protective measure.

Where two slopes join from outside vs. from the inside, creating an upside-down V.

Where two facets of a roof join at the very top.

A horizontal edge of your roof.

The exposed board on the eave of your roof. Fascia is what gutters are attached to, and it can be made of aluminum, wood, or vinyl.

An angled edge of your roof.

Where two rakes meet and form a triangle.

The exposed underside of where your roof overhangs the side of your house. Soffit can be made from wood, aluminum or vinyl. Sometimes vents are installed to provide better attic ventilation.

Dormers are small rooms that jut out from a facet of your roof. They almost always have a window, and have their own roof as well. Dormers can give your home curb appeal as well as provide extra space on the inside.

A metal component that's nailed to the decking at the end of a roof facet. Drip edge allows shingles to extend slightly over the edge of the roof, causing water to run off without damaging underlying materials.

Starter Strip is a strip of asphalt roofing applied at the eave. This provides an additional layer of material under the cutouts and joints of the first course of shingles.

Roof underlayment is a synthetic or felt material that's installed directly over your roof decking or sheathing. It adds an extra layer of protection from moisture and heat.

Some parts of your roof are more vulnerable because of the tendency for water to gather there. Ice and Water Shield is a waterproof membrane that is installed on or around these areas to protect your roof decking from wood rot and other issues.

Roof decking is the first layer in the roof system. Roof decking is either made of OSB (Oriented Strand Board), CDX plywood, or individual wooden planks. Decking is the foundation that all other roofing components are nailed onto.

The framing that supports the roof decking.