How to Waterproof around a Roof Vent

A leaky roof vent can cause all sorts of problems in your home. From compromising the structural integrity to harboring mold growth, a roof vent that isn't properly waterproofed can ruin the most important structure in your home.

Step 1 - Inspect Your Roof

Before waterproofing your roof vent, make sure that the shingles surrounding your roof vent are in good repair. Your best bet is to inspect your roof from the direction in which the worst winds normally come. Make sure to make a note of any dips or rises in the surface of your roof. Any areas on the roof that will allow water to run uphill and under shingles are an area that need to be fixed before waterproofing your roof vent. Also make a note of any shingles that have been warped or buckled.

Step 2 - Repair or Replace the Needed Shingles

Using a silicone sealant and caulking gun, seal any shingles that are of concern around the 3 open sides. Make sure that you use enough sealant to make sufficient contact with the buckled and warped shingles so that there is no gap under the shingle.

Step 3 - Waterproofing Your Roof Vent

After making sure that any shingles that need to be replaced or repaired are fixed, you are now ready to waterproof your roof vent. You can do this in a few different methods. The most common method is to use Black Jack Roof Caulking.

Step 4 - Sealant

Identify the edge where your vent or in some cases, metal flashing, meets your roof. There is no need to remove an existing sealant unless it is already peeling off or there is an excessive amount of sealant already there.  You will want to make sure that you apply a generous amount of the Black Jack to the joint where the vent meets your roof. You can then use your finger to smooth it out, making sure to cover any cracks or crevices.

Step 5 - Alternate Method

Another method to waterproof around roof vents is to use sheet metal around the vent. Using a thin piece of sheet metal, you can wrap it around the vent and secure it with rivets. Once you have the metal installed, use a silicone sealant and apply a generous amount of the sealant around the edges of the metal paying special attention to any cracks or gaps where the metal meets the roof.

Once you have applied the sealant make sure that you spread it out using either your finger or a small tool. Be careful not to use too much as it won't dry properly and could create more problems then it solves.

Step 6 - Finishing Up

Keep in mind, that if you are applying a sealant, you are essentially creating a barrier between any water and your roof. Water will take the path of least resistance. So if there are any other areas of weakness on your roof, the water will travel there instead. Regularly inspecting your roof will prevent costly damage in the end.