Airflow & drainage | Tile Roofing USA

Distinguish above-deck and attic air

Above-deck ventilation occurs between the tile and the roof deck. Eagle’s system describes an eave intake, a path beneath the tile and an upper exhaust. Attic ventilation concerns the space below the deck. Ask the designer to label both on a section drawing; an opening beneath the first tile course should not be assumed to ventilate the attic.

Preserve the intended openings

Closures, supports and ridge details must suit the selected airflow strategy while managing weather exposure. A vented ridge can require coordinated flashing, screening and a deck opening. Ask how the team will prevent mortar, insulation or later accessory work from obstructing a planned passage. Do not create new openings by removing protective components without a reviewed replacement detail.

Coordinate the attic side

For a vented attic, intake, exhaust and insulation baffles work together. PNNL explains that poorly coordinated vent types can disrupt the intended route. Select vents for the location’s rain, wind or ember exposure as well as their airflow characteristics. Our planning recommendation is to review the entire arrangement when replacing one vent rather than treating it as an isolated cosmetic change.

Review changes to drying potential

A new membrane or insulation strategy can change how the deck dries. Secure Guard 60’s instructions, for example, identify its resistance to vapor movement and call for moisture review. Ask the designer to consider the complete assembly before combining a new roof membrane with insulation below. Record the approved design so future contractors understand which openings and material relationships must be preserved.

Trace air and water through separate routes.

Distinguish above-deck and attic air

Preserve the intended openings

Coordinate the attic side

Review changes to drying potential

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