Bathroom Roof Vents
Bathroom ventilation has gotten complicated with all the vent types, duct routing options, and code requirements flying around. As someone who has installed bathroom exhaust systems in every situation, I learned everything there is to know about roof terminations. Today, I will share it all with you.
Why Roof Vents Matter
Probably should have led with this section, honestly—bathroom exhaust must terminate outside to remove moisture and odors effectively.
Vent Types
- Roof Cap: Dedicated penetration through roof
- Wall Vent: Alternative when roof access is difficult
- Soffit Vent: Generally not recommended (air can re-enter attic)
Installation Requirements
- Properly sealed flashing around penetration
- Backdraft damper to prevent air infiltration
- Insulated duct in unconditioned spaces
- Minimum slope toward termination
Common Mistakes
- Terminating in attic (causes moisture problems)
- Inadequate duct insulation (causes condensation)
- Poorly sealed roof penetration
- Excessive duct length reducing airflow
