Understanding the Two Approaches
When converting an attic into conditioned living space, your roof assembly determines comfort, durability, and utility bills. A vented roof keeps a continuous airflow path from soffit to ridge, while an unvented (conditioned) roof brings insulation and air barrier to the roof deck so the attic volume stays within the thermal envelope.
Vented Roof: Pros & Cons
Pros: Often cost-effective with batt or blown insulation; works well where continuous soffit and ridge vents are feasible. Cons: Requires rigid baffles to maintain airflow in shallow rafter bays; complicated around dormers/hips; air leaks can short-circuit performance.
Unvented Roof: Pros & Cons
Pros: Superior air sealing; easier detailing around complex rooflines; supports tight envelopes and better HVAC performance. Cons: Higher material cost (e.g., spray foam or rigid panels) and careful dew-point control to avoid condensation at the sheathing.
How to Choose
Consider rafter depth, existing soffit/ridge conditions, dormer plans, and your desired performance targets. In many NYC homes, unvented assemblies with the right ratio of rigid/spray foam to interior insulation deliver reliable moisture control and comfort. Commissioning (blower-door test) verifies results.
Explore best-fit assemblies and dew-point guidance in our energy-efficient NYC Attic Remodeling Service overview.