How to Install Roof Flashing for a Vent

What You'll Need
Caulk gun
Roofing nails
Vent flashing
New pipe vent flashing
Rain and repair collar
Extension ladder
Replacement shingles
6 inch knife

Roof flashing is standard around any pipe vent. However, over time the flashing can wear out and allow water to penetrate the interior of your home. Installing a new pipe vent flashing is easy and can be done in a short time. The tools needed are readily available at your local home improvement store.

Step 1 - Climb to the Roof

You’ll need to get on the roof to install a new flashing. Most will need an extension ladder. It is important that the ladder be secure and away from any electrical lines. If the pipe you are trying to repair is going to require you to work near electrical lines, it is best to call a professional. You will need to wear rubber bottom shoes to prevent you from sliding off of the roof. If the pitch of the roof is very steep you will want to have a foam block to help you stabilize. Remember; don’t risk your life to fix this flashing. If you need to, call a professional. 

Step 2 - Loosen Shingles

Once you are one the roof, or at the top of the ladder, you will need to use your knife to loosen the shingles at the top and along the sides of the existing flashing. You should be able to do this simply by sliding the knife under the rows of shingles. Be careful not to damage any shingles. If you do, you will need to replace them.

There will be roofing nails underneath the rows of shingles. You should remove them before pulling the shingles all of the way up. If you don’t, you will probably tear the shingles and will have to repair or replace them.

Step 3 - Install New Flashing

Once the shingles are loose and the nails are removed, you should remove the existing flashing. If it was installed properly, you will only have to remove a few roofing nails and lift it off of the pipe. If for some reason, you cannot remove the existing flashing, you can leave it in place and install the new one on top. However, most professionals would advise that the original flashing be removed.  

Now that the old flashing is gone, you can slide the new flashing over the pipe vent and maneuver it under the shingles above the pipe. Use one roofing nail in each corner of the flashing to secure it to the roof. Add a large bead of caulk in a half-moon shape around the flashing, and put the shingles back in place. This is when you would add a small dab of caulk to any nail holes in the shingles or replace any that you damaged. 

Step 4 - Complete Finish Work

If the new flashing doesn’t line up the same as the old one, you will need to add shingles or trim the existing shingles. You may want to add a rain or repair collar to the pipe to add another level of protection from water and keep your new flashing in perfect condition.

Installing a new flashing on a pipe vent is not very difficult. However, be sure to practice all safety precautions and call a professional if you need to.