The attic of your home needs proper ventilation to allow for the transfer of trapped heat and moisture to be removed to the outside. If not properly vented, your attic can cause inefficient heating or cooling as well as moisture build-up and mould. The simple solution to more airflow in your attic is through the use of gable vents. These are large vents at each end of the roof, near the gables, or peak, allowing for the air to travel through. You can install your own gable vents with some basic tools.
Measure the rough opening for the new vent. Inside the attic, using the gable vent as a template, locate a space close to the gable that will accommodate your new vent. The easiest shape of vent to install is a square or rectangle, but you may also want to purchase a hexagonal vent. Trace the opening between two studs in the attic.
Add additional bracing for the vent. Using your traced outline as a guide, add additional 2-by-4 boards horizontally and between the studs to support the vent at the top and bottom. This is called "framing in" the vent. Use 16 penny nails to secure the studs. There is now a frame all the way around the area where the opening will be.
Cut the hole for the vent. From the inside of the house, drill holes in the four corners of the framed opening, all the way through the wall. This will act as your guide from the outside. Using a reciprocating saw, cut out the opening for the vent by sawing an opening in the gable using the holes as a guide. Cut from the outside of the wall to the inside. When you are finished you will have a hole that allows the gable vent to slide in perfectly.
Install the cap flashing. Staple tar paper around the outside perimeter of the vent opening. Make sure that the paper is tucked underneath the siding at the top. Install the cap flashing into the vent opening, making sure that it also is tucked underneath the siding. Screw it down with drywall screws.
Install the gable vent. Place a liberal amount of exterior caulk around the flashing. Slide the vent into the opening and make sure that it is completely seated in the hole. Screw the flange down into the house to secure it. Attach the trim kit that comes with the gable vent. This will hide the flashing and the opening in the wall. Repeat the process for the other gable.