How to Make Soffit Vent Channels

Count the number of soffit vents your attic needs. Builders recommend installing 1 square foot of soffit vent for every 10 square feet of area in your attic. Measure the floor space of your attic, and multiply the its length by width to determine square footage. Divide this total by 150, and round up to determine the square footage of vent space your attic needs. Calculate the square footage of each vent area, and divide the overall ventilation needs by this number, rounding up. This number is the amount of vents for you to install.

Locate areas in the attic to install soffit vents. Place vents roughly evenly around exposed areas in the soffit. Clear insulation from the vent area to allow air flow once you install the vent, and avoid storing items directly above soffit vents.

Measure the vent area on each soffit vent – not including the lip around the vent’s edge – to determine the size of a hole you must cut in for each vent. From the outside, so you can reach the soffit easily, use a saber saw to cut a proper sized hole, spacing it equally between rafters.

Add screw holes to the vents. If your vents came with predrilled screw holes, skip to the next step. Use an electric drill to drill a hole in each thin side of the vent’s lip area.

Slide vents into the holes you cut in Step 3. The vent’s lip should extend beyond the hole to prevent it from falling into the attic. Secure the vent to the soffit using wood screws through holes in the lip.