Materials to Use for Vent Flashing

Vent flashing needs to be used in a variety of applications. You can find flashing around roof vents, duct vents, and gas vents. Depending on the type of vent you are working with, the materials needed can be different. Here’s what you need to know about vent flashing materials.

Thermoplastic Vent Flashing

Thermoplastic vent flashing is not as popular today as it once was. It is inexpensive to use, but you get what you pay for. Vents that are placed on the roof are exposed to extreme temperatures, and UV light from the sun. This will deteriorate plastic of any kind fairly quickly. There are some advantages to this type of material though. You don’t have to worry about using caulk with a thermoplastic base. They also won’t rust or corrode.  Since most people don’t enjoy climbing up on their roofs to make repairs, thermoplastic flashing isn’t the best option for roofs. If you do choose to use this material make sure you are finding a high quality product that has a UV protective coating on it to minimize the suns damage.

Galvanized Vent Flashing

Galvanized steel is most commonly seen in flashing that is used with gas and plumbing applications. It’s used occasionally on roof vents as well. Galvanized flashing often won’t require any kind of caulking depending on the flashing you purchase. The cost can vary greatly as well. You can find the flashing anywhere from $5 to $150, depending on the size, the application, and the type you end up with.

Aluminum Vent Flashing

Aluminum is a popular choice, but not always a good one. Flashing may need to be soldered and you can’t do this with aluminum. Aluminum is also prone to rust and corrosion, which could end up causing leaks later down the line. Aluminum doesn’t generally hold up as long as the roof will, which means you will be forced to repair or replace the flashing before it’s time for a new roof.

One Part Flashing Systems

One part flashing systems are exactly what they sound like. The flashing is one piece that will set over the vent or pipe and is usually caulked to the roof. While it’s easier to install a one part system, it’s not always smart. One part systems can’t expand and contract as the roof and pipe does which can end up causing gaps and leaks later on.

Two Part Flash Systems

Two part flash systems use a base covered by the roof material, then covered with counter flashing. These are more difficult to install, but well worth the effort. Humidity and temperature changes can cause the wood to swell, expand, and contract. A two part flashing system will allow natural expansion and contraction without causing gaps that can lead to leaks later on.

The type of vent you have will play an important role in what kind of flashing is required. If you are unsure of what you need, ask a professional for guidance. Having the right flashing materials can make the difference between a leaky roof and one that will last a lifetime.