Roofing contractors may recommend adding or correcting intake and exhaust ventilation during replacement. The reason and required approach depend on the attic or roof assembly and local conditions.
Ventilation can be part of moisture control
In vented attic assemblies, airflow can help remove excess moisture and moderate attic conditions. The design should also consider air sealing and insulation.
Intake and exhaust need to work together
Adding exhaust vents without adequate intake can fail to create the intended airflow path. Ask the contractor how the whole ventilation system is being evaluated.
Codes and manufacturer requirements matter
Local code and roofing-product warranty requirements can affect the minimum ventilation or accepted assembly.
Ventilation can change replacement scope
Ridge vents, soffit intake, baffles, roof vents or changes to existing openings can add materials and labor to a roofing proposal.
Ask for the calculation and reason
Before accepting an added ventilation line item, ask what problem it solves, what standard is being followed and how it relates to the roof replacement scope.
Sources and further reading
- National Roofing Contractors Association — Roofing Resources / Attic Ventilation
- U.S. Department of Energy — Consumer Guide to Durable Attics