Roofing Terminology: 22 Terms You Need To Know

February 19, 2021

Roofing Terminology:
22 Terms You Need To Know

Have you ever found yourself looking for contracting services and wishing that you had a glossary to break down the terms? Any time you delve into a new industry or niche, you’ll find yourself surrounded by terminology that might be all new to you. This is certainly true when you’re in the market for a new roof or when you need roof repairs. But ordering roofing work doesn’t have to be overwhelming. In today’s blog, we’ll break down 22 different roofing terms that you’ll need to know in order to choose the best roof for your home.

1. Absorption

This refers to the roof’s ability to absorb water and other moisture. Often, moisture barriers are installed within roofs in order to make them less absorbent, or less absorbent materials are used on the surface so as to prevent leaks from getting into the home.

2. Accelerated Weathering

This is a test that roofing manufacturers sometimes conduct to ensure that their roof can stand up to the elements. The roofs are placed in a controlled environment in which they are exposed to extreme heat, cold, moisture, etc., to see what the effects will be compared to the unexposed material.

3. Air Barrier

In the same way that windows have to keep their air leakage to a minimum, roofs should have a strong air barrier. The air barrier is used to block the flow of air from one side of the roof to the other. The layering of materials and types of materials used can impact the air barrier.

4. Algae Discoloration

Houston is a hot climate, but it is also quite humid. For this reason, your roof might be susceptible to algae growth and damage that comes from it. You might sometimes notice greenish discoloration that is easy to mistake for fungus. A roofing professional can help you determine that it’s algae and find a way to remove it.

5. Asphalt

Asphalt is a semi-solid form of petroleum. In texture, it is sticky and viscous, and often used to adhere different layers of roof together. GAF’s glossary of roofing definitions refers to asphalt as a pitch.

6. Asphalt Plastic Cement

Sometimes known as flashing cement or mastic, asphalt cement is often used to bind other roofing materials together. This is the material that’s used between each layer of low-sloped layered roofing, such as BUR roofs.


This is short for the American Society for Testing and Materials. They test the materials used in roofing projects for durability, weather resistance, and energy efficiency, before those materials are put out on the market.

8. Built-Up Roofing

Built-up roofing (BUR) is a low-slope or flat roof made up of several layers of insulation and asphalt. This is a common roofing material for commercial roofing because it is flat and complex enough to be durable.

9. Bundle

When you have a shingle roof installed, shingles will come in bundles. This is also the case when you need to buy new shingles to repair missing or broken shingles. There are typically 3, 4, or 5 bundles of shingles per square.

10. Decking

Your roof is more than just the surface materials. Roof decking, sometimes called sheathing, is the plywood underneath on which the roofing materials rests. This dictates the shape of the roof and holds up the roofing materials.

11. Dormer

On sloped roofs, you often see smaller slopes built into the surface of the roof. They include windows. These are called dormers, and usually offer lighting into the attic.

12. Downspout

The downspout is a large pipe that is connected to the bottom of your roof gutters. As your roof gutters funnel water through their system, the downspout directs them away from the house, protecting your roof, walls, and foundation from potential water damage.

13. Eaves

The eaves of the roof are the lowest edges, which hang over the house and walls. The eaves are typically where the gutters for the roof are attached.

14. Fasteners

The roof’s surface has to be fastened to the roof decking in order to withstand heavy winds and storms. The nails that hold this in place are called fasteners.

15. Fire Rating

It’s important for your roof to be able to stand up to the elements, not just wind and rain. A fire rating is given between A and C, with A being the most fire resistant.

16. Flashing

Flashing is loose sheet metal that’s nailed down around any vents in the roof. This helps to protect those openings from water damage. Flashing has to be checked occasionally to make sure it hasn’t come loose.

17. Ice Dam

An ice dam occurs when the heat from inside the house meets with the snow or ice on the surface of the roof, melting the snow on the bottom but not above. As the melted snow is not melted, it soon re-freezes the water beneath, causing an ice dam. Though this is not a frequent problem in Houston, on the occasion that it occurs, it could mean risk of water damage.

18. Laminated Shingles

Laminated shingles contain multiple layers of tabs in order to boost durability and lessen the chance of leaks. GAF Roofing offers high quality laminated fiberglass shingle roofs.

19. Rafters

The rafters are built on the inside of your home but are an integral part of the structure of the roof. These are the sturdy support beams that keep the roof from caving in over time. The decking and material rests on these.

20. RCAT 

RCAT is the Roofing Contractors Association of Texas. Although Texas has no legal requirements for roofers to be licensed, RCAT offers licensing to companies who have shown themselves to be financially stable, ensured, and legitimate. A roofer who wants to go above and beyond in Texas will apply for RCAT licensing.

21. Shed Roof

A shed roof is less common than hip or gable roofs when it comes to sloped roofs. This roof is sloped on only one side, much like an awning but for a full roof. This is often used with buildings where one side of the building is taller than the other.

22. Underlayment

Underlayment or felt is roofing paper sealed to the higher levels of the roof with asphalt. It is used as a moisture barrier to help protect the roof from leaks.

Need help to understand your roof repair or replacement? Talk to an expert. Contact Houston Roofing today for more information or to get started with a free estimate.

Request Your
Free Roof Estimate