Did Your Insulation Contractor BLOCK Your Soffit Vents?, by Crawl Space Ninja on YouTube. 9 min 21 s.
- Video length
- 9 min 21 s
- Time to do it
- 1 to 2 hours
- Difficulty
- Easy
- Steps
- 8
What you need
Steps
Learn the airflow path first. Outside air should enter through the soffit vents under the eaves, travel up between the rafters and leave through the ridge vent at the top.
On a cool morning, stand outside under the eaves and hold a tissue or smoke pen near a soffit vent. A working vent pulls the tissue up or draws the smoke in.
Go into the attic with a light and look along the eaves where the roof slope meets the ceiling joists. Note any spot where insulation touches or covers the vent openings.
Check whether rafter baffles are fitted. A baffle is a rigid channel stapled between rafters that holds insulation back and keeps a clear airway from the soffit to the ridge.
Pull back or rake away the insulation that has spilled over the vents. Wear gloves and a mask, and step only on the ceiling joists, never on the drywall between them.
Staple a baffle to the underside of the roof deck between each pair of rafters, with the open end sitting over the soffit vent and the channel running up the slope.
Push the insulation back so it sits against the outside of the baffle and stays below the top edge. Do not compress it or stuff it into the gap.
Check the ridge vent and any gable vents at the same time, then redo the tissue or smoke test to confirm air is moving again.
Tips and common mistakes
Air seal the attic floor before you add insulation, because warm moist air leaking up causes more problems than the insulation itself.
Look for rusted nails, damp sheathing or musty smells near the eaves, which point to trapped moisture and poor venting.
Never lay a batt or blown-in insulation tight against the roof deck at the eaves, as that is exactly what blocks the airflow.
Take photos of the vent openings before and after the job so you have proof if a contractor does the work next time.
Questions
How do I know if my soffit vents are blocked?
Check from inside the attic for insulation touching the roof deck at the eaves, and test airflow outside with a tissue or smoke pen. Weak or no pull at the vent usually means a blockage.
Can I just remove the insulation from the vents?
You can clear it, but it will slide or blow back over the opening. Fit rafter baffles first so the insulation stays out of the airway.
Does a blocked soffit vent really matter in a hot climate?
Yes. Without air coming in at the eaves, the ridge vent cannot pull heat out, so the attic and the rooms below get hotter and your cooling bill goes up.
This guide was drafted from the video's details and general task knowledge. It has not been checked against the full video. Check the video and relevant product instructions before following a procedure. Report a correction.
