How do you keep bugs out of soffit vents with a screen?
Why not use the finest screen you can find
Every screen cuts a vent's net free area. Window screen has openings smaller than 1/16 inch, below the code's minimum for vent openings, and in Georgia it collects spring pine pollen and dust until the intake is nearly choked. Gnats in the attic are not a real problem. Wasps, mud daubers, birds, bats and squirrels are, and mesh around 1/8 inch stops all of them.
Choosing the material
- Aluminum or coated fiberglass insect mesh: easy to cut and install, but squirrels chew right through it.
- Galvanized or stainless hardware cloth, about 1/8 inch: the durable choice for wood soffits with cut-out vents or anywhere animals are a concern.
- Perforated vinyl or aluminum soffit panels: the perforations already act as the screen, so no extra mesh is needed.
Wasps and the soffit
Paper wasps build on the outside of soffits, and some insects nest in the gap above a soffit panel. Check that panels are fully seated in their channels, that the trim along the fascia and the wall leaves no gaps, and that the corners where the soffit meets the house are closed. A screen does nothing if insects can walk around it.
If you add mesh behind an existing vent, account for the lost airflow: the intake may need more total vent area to stay balanced with the exhaust. See roof ventilation basics for the balance and roof anatomy explained for where the soffit fits.