Venting a Dryer Through the Roof vs. the Wall

A short horizontal run with a slight downward pitch lets lint and condensate exit naturally. Cleaning is straightforward from ground level.

Sidewall hoods are also easier to inspect, which means problems get caught before they become long dry cycles.

Second-floor laundry rooms in the middle of a floor plan sometimes have no reasonable path to an exterior wall.

In that case the vertical run should be rigid metal, insulated where it passes through unconditioned attic space to limit condensation.

Vertical runs let lint fall back toward the dryer, which accelerates buildup at the base of the run.

Service requires roof access, and roof caps with screens or restricted dampers clog quickly.

• Lint settles back down the vertical run
• Condensation forms in cold attic sections
• Cleaning requires roof access
• Flashing becomes a leak risk over time

Rigid galvanized or aluminum, foil-taped joints, no screws into the airstream, and a damper-equipped termination.

Vinyl and thin foil accordion hose should never appear anywhere in the run.