Floor Void Ventilation Requirements

Elevated buildings in a zones in an elevated building located in an a zone any flood zone beginning with the letter a the lowest floor used for rating is the lowest elevated floor with the.

Floor void ventilation requirements.

On shrinkable soil where heave could take place a larger void is required to allow for movement according to the volume change potential. The building regulations approved document c states suspended timber floors and suspended concrete floors including block and beam have a provision for ventilation on two opposing external walls of not less than 1500mm per metre run of external wall or 500mm per metre of floor area whichever works out to give the greater amount of ventilation. A suspended floor is a ground floor with a void underneath the structure. High volume change potential 150mm 300mm total void.

However the floor structure is supported by external and internal walls. Another common way these vents can be blocked is by an extension with a solid floor being built onto a property without providing proper access to the original vents. Duo pitch roofs greater than 200 pitch or greater than 10m span should have additional ventilation at the ridge to assist airflow through the roof void equivalent to at least a 3 mm wide continuous gap. Ventilation openings should be provided on at least two opposite sides.

Voids should be ventilated by openings providing not less than 1500mm 2 per metre run of external wall or 500mm 2 per m 2 of floor area whichever gives the greater opening area. The recommended minimum area of ventilation required for under a suspended timber floor is 1500mm 2 for every metre of perimeter of the structure. Telescopic gas vent outlets 1201 1201ab 1206 gvl900 the combined units will allow ventilation outlets to either a sub floor void or via a range of adaptors to a venting layer and allow the provision of a minimum of one complete volume change per 24 hours as required by the nhbc. Additionally if the span is greater than 10m the overall ventilation area should be increased to at least 0 6 of the total roof area.

The timloc vent units will achieve. Where the exterior ground level is too high to carry air to the sub floor void in a straight line a telescopic underfloor vent should be attached to the back of the air brick to conduct and protect the airflow across up to 5 brick courses. And the floor level of the garage is below the level of the building use the garage floor as the lowest floor for rating. Supports underneath the floor are permanent and.

This requires a minimum of 3 500 mm2of net open area for every 1 m2of the house plan floor area.