How to Install a Dormer Vent

What You'll Need
Crow bar
Dormer Vent

If you want to install a dormer vent in your roof, you will need to remove a lot of the shingles from the area and later  fit them back on. Dormer vents were designed to be fitted into the eaves of buildings, but many people now add them to the roof itself, and they look perfectly alright in this position. The downside is that dormer vents require a lot of flashing, which can be very tiresome to insert, particularly when you have to refit a large number of shingles. Installing a dormer vent is not difficult, however, and you should be able to complete this task within a day.

Step 1 - Mark the Vent

When you are ready to start installing your dormer vent, begin by marking out the position on your roof. Take the vent onto the roof, and draw a line in chalk around it. You should then remove all of the shingles covered by that outline, plus all of the ones in the middle, and an area beyond the chalk of about 4 inches. When this has been done, you should then go in, and mark the position of the vent on the inside, focusing on the gap to show you the best position.

Step 2 - Cut out the Shape

Once you have marked out the shape of your dormer vent, you can then begin to cut out the wood of your attic. Using a saw, cut down the wood in the area marked on the inside, and then  remove the insulation so that you have a full hole from the attic to the outside of the roof. You should cut the hole slightly smaller than the actual vent, and then trim it as needed.

Step 3 - Fit the Vent

Screw the inside of the dormer vent into position. Use four screws for each of the corners, and then add any other than you feel is necessary to support the weight. Once you have done this, you can then proceed to the outside. Push the outside part of the vent onto the inside, and secure with nails.

Step 4 - Add Flashing

You should then cut your flashing to fit around the edge of the dormer vent. Add nails around the sides of the flashing, so that it is tightly buttressed against the vent, and then caulk all of the edges. Make the vent and the flashing as waterproof as possible.

Step 5 - Add the Shingles

Add enough shingles to secure the flashing into position. Secureby adding a single roofing nail through the middle of each, and then add some caulk or roofing tar around the edges of the shingles. Caulk again around the vent, and then leave to dry.