Air sealing + R60 attic floor plan with limited ventilation–sanity check? - GreenBuildingAdvisor

Air sealing + R60 attic floor plan with limited ventilation–sanity check? novawaly | Posted in General Questions on February 13, 2026 04:11pm Hi all, I’m looking for feedback on an attic air-sealing and insulation plan. I’ve been digging through GBA articles and want to make sure I’m not creating a moisture trap or unintended airflow issue. House is: Cold/mixed climate (Zone 4a U.S.), Roof is relatively new (5 years old), No ridge vent. Only current exhaust is a powered attic fan in the center of the roof (normally off). Soffit vents are present. Attic has knee wall sections and a front overhang area with columns. Rafters are ~7″ deep. Existing insulation is fiberglass batts on the attic floor. No visible mold, no frost on nails, no ice dam history. There are two attic zones 1. Main attic floor areas around HVAC. 2. Overhang/front patio section where soffits are set far back and geometry is tight. Ventilation There is no ridge vent. Soffits exist. No gable vents. In the more “normal” eave areas, I can see existing styrofoam baffles under the roof sheathing, but insulation is pushed right up to them. In the front overhang section: • Soffit vents are set way back beyond the exterior wall. • No visible baffles. • Very difficult access. • Air appears to move relatively freely into the main attic cavity. I do NOT currently run the powered attic fan (I’ve read that with poor air sealing it can worsen stack effect issues). Working Plan: Aggressively air seal the ceiling plane: To...