Replacing a roof gable vent with a larger vent is an easy way to add ventilation in an attic. Ventilation is necessary to lower summer temperatures and prevent moisture damage from condensation in the winter.
Tip # 1
Take measurements from the inside on each gable end for the largest rectangle that will fit between the sloping areas of the roof. Purchase a vent that is already screened on the inside. Remove the old vent.
Tip # 2
Frame out a rough opening on the inside that is ¼ of an inch larger than the dimensions of the vent with dimensional lumber to match what is already there. Use a level to make the opening plumb and square. Drive a nail through to the outside on each top corner.
Tip # 3
Mark the dimensions on the outside of the house with a pencil, using the nails as a guide for the top. Set the circle saw blade depth to the thickness of the siding and sheathing, if any, and cut the opening. Make sure you wear safety glasses.
Tip # 4
Caulk underneath the edge of the vent all around to keep rain and snow out and then nail the vent following the manufacturer’s instructions. Repeat on the other side of the house.