Why Is Attic Ventilation Important? What Homeowners Should Know, by Above Roofing on YouTube. 5 min 2 s.
- Video length
- 5 min 2 s
- Time to do it
- 1 to 2 hours
- Difficulty
- Medium
- Steps
- 7
What you need
Steps
On a cool morning, climb into the attic with a torch. Look for rusted nail tips, dark or damp roof decking, mould spots, and insulation pushed tight against the eaves.
Trace the airflow path. Fresh air should enter low at the soffit vents under the eaves, run along the underside of the roof, and exit high through ridge or gable vents.
Push insulation back from the soffit openings so air can get in, then fit foam or plastic baffles between the rafters to keep a clear channel from the eave to the ridge.
Compare your vents. Gable vents sit at the ends, ridge vents run along the top. Ridge vents usually give more even exhaust along the whole roof.
Check that bathroom and kitchen fans run ductwork all the way outside through the roof or a wall, never dumping warm moist air into the attic space.
If you have ridge vents, ask your roofer whether the old gable vents should be closed off so the intake and exhaust stay balanced.
Test the result on a hot day. The attic should sit close to the outdoor temperature, and a tissue held near a soffit vent should be pulled gently inward.
Tips and common mistakes
Never let a bathroom fan end in the attic, or the moisture lands straight on the cold decking.
More vents is not automatically better; intake and exhaust need to match or airflow stalls.
Check for ice dams at the roof edge in winter, since they often mean warm air is escaping upward.
Attics get dangerously hot, so work early, wear a dust mask, and use a stable ladder rather than stepping between joists.
Questions
How do I know if my attic is properly ventilated?
On a hot day the attic should feel close to the outside temperature, with no damp smell or condensation on the decking. Rusted nails and curled shingles are warning signs of poor airflow.
Do I need both soffit and ridge vents?
Ideally yes. Soffit vents let fresh air in low and ridge vents let hot air out high, which keeps a steady current moving under the roof.
Can I add attic vents myself?
Soffit baffles and clearing insulation are easy DIY jobs. Cutting new holes in the roof or deck is best left to a roofer, since a leak there can rot the structure.
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.
