Round Static Vent Installation Guide

Quick answer

Installing a round static vent involves cutting a precise hole, securing the vent with flashing and sealant, and ensuring proper net free area for attic ventilation.

Installation steps

1. Choose the vent location: Position the vent on the roof slope between rafters, avoiding ridges or valleys. Ensure at least 1 sq. ft. of net free area per 300 sq. ft. of attic floor space. Common mistake: placing the vent too close to a ridge can cause water pooling.
2. Cut the roof opening: Trace the vent base on the roof, then cut the hole using a jigsaw or reciprocating saw. Cut slightly inside the line to ensure a snug fit. Checkpoint: the hole must be smaller than the base flange to allow proper flashing overlap.
3. Apply sealant and flashing: Apply a thick bead of roofing sealant around the cutout. Place the vent's base flashing over the opening and press firmly. Secure with roofing nails or screws into the decking. Common mistake: using too little sealant leads to leaks. Cover all nail heads with sealant too.
4. Attach the vent dome: Fit the round dome over the base and secure with the provided screws or clips. Ensure the bird screen is seated properly inside the dome before tightening. Checkpoint: a misaligned screen can reduce net free area or allow pest entry.
5. Seal and test: Apply a final sealant bead around the dome-to-base joint. After curing, test by spraying water from a garden hose at the base while checking the attic for leaks. Common mistake: skipping the water test. A small leak can cause hidden mold over time.

Product used in this guide

• VX25 Series Large Capacity Round Static Vents: High-capacity ventilation providing 144 sq. in. of net free area per vent, with a built-in bird and insect screen. This large net free area means fewer vents needed for your attic, and the screen prevents wildlife entry without reducing airflow.