Installing a Gable Vent Step by Step

A gable vent is an important part of the heating and cooling of your home. Without it, you could be wasting a lot of money. An attic without a gable vent can be up to 60 degrees hotter than the temperature outside because the hot air is trapped in your home. In the winter, the moisture from the heat in your home can evaporate and begin to rot your insulation and roof joists.

Installing a gable vent is not difficult, but it does require the use of power equipment and ladders. Safety precautions should be taken at all times.

Step 1 - Prepare

Using either the template that comes with the vents or the vent itself, mark the size of the vent on the inside of the attic wall.

Build a matching frame out of 2x4 boards between the studs. Be sure to leave at least a 1/8-inch clearing for the vent. After the frame is built, drill holes in each corner, clear through to the outside.

Step 2 - Cut Holes

Once the holes are drilled, use a chalk line to connect them, forming the outline of your gable vent. Attach a bi-metal blade to your reciprocating saw and cut out the outline of the vent.

Use a plumb bob in the opening of the vent to determine the flange location. Mark this with a pencil on the siding. Adjust the blade on the circular saw to the depth of the siding and cut along the outline. Remove the siding from around the opening. Apply building paper around the opening and under the siding as a protective barrier and staple it to the house.

Step 3 - Install

Apply a bead of caulking around the opening so that when you slide the vent in there will be a watertight bond. Slide the metal flashing around the vent. Move the vent around until the flange is under the paper and flashing. Mount the vent to the house with nails or 2-1/2 inch screws. Apply a bead of caulking around the entire vent and smooth it out with a scraper or your finger.