How to Install Soffit Eave Vents on Your Home
How to Install Rectangular Soffit Vents: Layout Vent Width: Pop two parallel chalk lines on the soffit board with the distance between them 1" less than the outside width of the soffit vents. Layout Vent Length: Mark the location of the ends of each soffit vent 1" less than the outside length of the vent, making sure each vent falls between the soffit joists or rafters.