How to Replace a Dormer Vent How to Replace a Dormer Vent

What You'll Need
Crow bar
Replacement dormer vent

Adding a new dormer vent to your roof can be a difficult project, but if you already have the hole and the positioning for a vent, then you should be able to manage to do this within a few hours. You do not even need to have a vent which matches exactly the proportions of the old vent, as you can build up wooden supports around the hole to accommodate the new vent. Once you have begun this project, it is necessary to complete it rapidly, as holes in the roof can let in damp and condensation overnight. Make sure that you have all of your materials gathered together before you start removing the old dormer vent and replacing it with a new one.

Step 1 - Remove the Old Dormer Vent

Start by unscrewing the internal supports for your dormer vent. You should then proceed to the roof, and remove the shingles that have been placed around the vent. Take up the flashing, and keep this to one side, as it should be suitable for use with your new dormer vent. When you have done this, you can then use your knife to prise off the caulk around the dormer vent. Clean as much of this off as you can, and then unscrew the vent. Keep the screws if you can. Once all of this has been removed, you can prise off the dormer vent using a crow bar.

Step 2 - Add the New Vent

Place the new vent into the space in the roof. If your vent is a little smaller than the previous version, you may want to add some lumber supports to the inside and outside of the hole. Cut some lumber down to size, and then nail it between the beams of the roof. You can then place the dormer vent into position on top of the lumber, and screw it down. Add caulk around the edges of the vent. You can repeat the process inside, screwing the internal support for the vent into added lumber, and then sealing with caulk.

Step 3 - Finish Up

When you have sealed the vent, you can then proceed to re-lay the flashing around the vent. Add a little caulk to the back of each piece of flashing, and nail it down securely. You should then add the rest of the shingles, including adding some extra shingles if the dormer vent is slightly smaller. Make sure that you cover the vent area in caulk, and you can also use a roof tar to ensure that the area is completely sealed.

On the inside, make sure that the vent is caulked, and then caulk around any added pieces of wood. Leave the caulk and tar to dry overnight, and then check the next day to ensure that the area is completely watertight.


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