# What are the signs of blocked soffit vents?

*Published 2026-05-31T09:00:00-07:00 · Updated 2026-07-18T09:00:00-07:00 · Best Roofing Answers*

## Answer

Blocked soffit vents commonly show up as summer attic temperatures above 130°F, winter ice damming at the eaves, mold or frost on the underside of the roof deck, and premature curling of shingles above the affected soffit — any one of these signals a ventilation deficit under IRC R806 code minimums.

## Why soffit vents get blocked

Per DOE and IECC guidance, the most common cause is blown-in attic insulation covering the vent openings without baffles. Retrofit polystyrene baffles between rafters preserve airflow at each vent — a low-cost fix that restores the 1:150 (or 1:300 with balanced ridge exhaust) net free vent area required by code.

Painted-over soffit panel perforations are another common failure — the paint film seals the tiny holes and the vent becomes decorative only. A visual check from below is enough to spot this.

## Also asked as

- attic soffit vent blocked
- signs of poor attic ventilation
- insulation blocking soffit vents
- how to tell if soffit vents are working

## Sources

- [IRC R806 / IECC — Attic Ventilation](https://codes.iccsafe.org/content/IRC2021P2/chapter-8-roof-ceiling-construction)
- [U.S. Department of Energy — Attic Ventilation](https://www.energy.gov/energysaver/weatherize/insulation)
- [International Residential Code (IRC), Chapter 9 — Roof Assemblies](https://codes.iccsafe.org/content/IRC2021P2/chapter-9-roof-assemblies)

## Related

- https://bestroofinganswers.com/ventilation/attic-heat-roof-issues
- https://bestroofinganswers.com/q/ridge-vent-vs-box-vent
- https://bestroofinganswers.com/q/how-to-prevent-ice-dams

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Published: 2026-05-31T09:00:00-07:00
Modified: 2026-07-18T09:00:00-07:00
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