Roof of house

Glossary: 10 Roofing Terms You Should Know

While you may know the basic differences between an asphalt roof and a tile roof, do you know what roof blisters are? How about decking and counter flashing? When it comes to roofing, many terms may be unfamiliar to the average homeowner. This can make shopping for a new roof or coordinating roof repairs more difficult. It can also make understanding roofing repairs more challenging.

Below we review ten common roofing terms you should know. Keep reading to learn more.

Asphalt Coating

The asphalt coating on your roof is a viscous layer of asphalt applied to your asphalt shingles and to which granules or other surfacing materials are applied. This coating has protective qualities, and the granules that are embedded into it help prevent weathering.


Blisters are bubbles that sometimes appear on the surface of asphalt roofing. They are typically caused when a poorly ventilated roof suffers excessive heat. When asphalt shingles heat up, trapped moisture inside the shingles can expand, creating the bubbling or blistering effect. When your roof is poorly ventilated, blistering is more likely as heat becomes trapped in your attic or crawlspace, superheating your roof.

If your roof has blistering, the damaged shingles will need to be replaced. You should also schedule an inspection with our professional roofer to determine what was causing the blistering so that you can prevent it from happening again. Sometimes a simple installation of a solar attic fan is all you need to avoid future blistering.

Counter Flashing

This portion of your flashing attaches to a vertical surface to prevent water from getting behind the base flashing. You will likely find counter flashing in areas where your roof meets your chimney or where a lower level of the roof meets the side of your house. You will also find counter flashing installed around your skylight. Counter flashing is necessary to keep moisture out of your roof. It works together with your base flashing to ensure that your roofing is water tight.


An important part of your roofing system, decking is what your roofing materials are applied to and is sometimes referred to as sheathing or the "structural skin" or your roof. Decking is typically made of plywood and is laid over the trusses and joists of your roof. This creates a flat surface for your shingles or other roofing to be applied to.

Foam Roofing

This is a type of roofing system for flat roofs that uses sprayed polyurethane foam (SPF) and coatings to create your roofing system. Foam roofing is popular because it is energy-efficient and long-lasting. It is also lightweight and self-flashing. The foam is sprayed onto your roof in liquid form, after which it expands and dries within seconds. Foam roofing also adds insulation to your roofing, helping lower utility bills and reducing heating and cooling loss from your building.

Ice Dam

These occur on the lower roof edge when snow melts and re-freezes on the overhang. Ice dams force water up under the shingles, creating moisture problems and leaks. While these are mostly associated with snowy climates, they can happen in Arizona. Additionally, dams can also be formed by built-up debris on your roof. When water gets trapped, it looks for a way out and can be forced into pin-sized holes in your roof, leading to leaks and other problems.

If you are struggling with ice dams or other dam issues, reach out to our roofers to find out what can be done to repair the problem and prevent it from happening again in the future.

Modified Roofing

Modified roofing refers to the modified bitumen (MB) roofing system. This type of system is very similar to built-up-roof (BUR) systems and is used in areas that experience extreme weather and temperatures. There are several different application methods, including cold and torch applications. You can also get self-adhering MB roofing.


Shading is what is considered a visual inconsistency with asphalt shingles. It refers to slight differences in color that occur during manufacturing. Often color shading of your roof is only noticeable from certain angles or in certain lighting conditions. Darker-colored shingles are most likely to have issues with shading.


Tabs are a feature on shingles and are the exposed part of the shingle, defined by cutouts. Tabs come in a wide range of sizes, shapes, and configurations, depending on the type of shingles you have.

Common tab configurations for shingles include:

  • 3-tab shingles
  • Free-tab shingles
  • No-cutout shingles
  • Random-tab shingles
  • Square-tab shingles

3-tab shingles are some of the most common. Traditional asphalt shingles tend to be 3-tab shingles.


When a new roof is applied to an uneven surface, telegraphing can happen. Telegraphing is when a shingle becomes distorted due to issues with the roof's substrate. Typically telegraphing is caused by problems with the underlayment or the decking. For example, if an underlayment is installed with wrinkles in it, this can cause telegraphing. Alternatively, if the decking is installed with incorrect spacing, it can expand and shift, pushing up the shingles. It is not an issue with the shingles themselves.

For more roofing terms you should know, review our blog here.