Quality.
    Minimum
    England

    Minimum eaves ventilation for pitched roofs

    7,000 mm

    For specific pitched roof constructions, a minimum continuous eaves ventilation opening of 7000 mm²/m is a common requirement

    Every figure for this topic is on one page: Roof void ventilation, access and fire compartmentation

    Read the full answer

    For specific pitched roof constructions, a minimum continuous eaves ventilation opening of 7000 mm²/m is a common requirement. This ensures adequate airflow into the roof void to prevent condensation.

    Basis in regulation

    How to check it on site

    Measure the effective clear opening area of eaves ventilation to confirm it meets the minimum specification.

    Common failure

    Ventilation grilles or gaps being too small or obstructed by insulation, preventing proper airflow.

    Last updated 23 August 2026. This is our editorial summary of publicly available regulation, not building control approval or a warranty determination.

    Related dimensions at this stage

    Minimum

    Minimum strap dimensions for holding down

    30 mm

    A strap used for holding down purposes, particularly in roof structures, must have a minimum cross-section of 30mm x 2.5mm and be at least 1000mm long to effectively resist uplift forces.

    Minimum

    Equivalent ventilation areas for a cold roof

    10,000 mm²/m at pitched eaves; 25,000 mm²/m at low level on flat or shallow roofs; 5,000 mm²/m at the ridge

    Cold roof construction with the insulation at ceiling or deck level.

    Minimum

    Clear air gap above insulation in a cold flat or shallow roof

    50 mm

    Cold flat roofs and cold roofs pitched below 15 degrees.

    Minimum

    Ventilated batten space beneath a roof underlay

    25 mm

    Roofs designed with a ventilated space beneath the underlay, including counter-battened details.

    Minimum

    Minimum tile or slate width at a verge

    150 mm

    All verges on plain tiled, interlocking tiled and slated roofs.

    Minimum

    Holding-down strap fixing and dimensions

    30 mm

    Roof holding-down straps should be 30mm x 2.5mm in cross-section and at least 1 metre long

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