Roof Void Ventilation Building Regulations

Pitch roof this is where tiles or slates are used and a void is usually created underneath.

Roof void ventilation building regulations.

A room that the rooflight is to serve will need to be ventilated. The requirements will be met by the ventilation of those roofs where the moisture from the building can pass through the insulation. Open roof void building regulations state. A roof void above an insulated ceiling.

Roof space ventilation introduction building regulation approved document c2 refers to bs 5250. Both building regulations and nhbc require ventilation to be provided in roof spaces. Where the void is open eaves to eaves air flow is effective along the longer sides of the building. Ventilation can be achieved by using the rooflight for both rapid and background venting.

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. Airtrak assists specifiers builders and specialist contractors in helping them to meet the requirements of the building regulations in relation to the important issue of roof void ventilation and the control of condensation. To enable compliance with the requirements of the building regulations to be demonstrated full details of the new roof will be needed including. Brett martin recommend the use of high level ventilation in addition to eaves ventilation in all cases as it utilises the natural thermal uplift in a roof void.

Sufficient cold roof ventilation. Ventilation of the existing roof void s will have to be considered as air must still be allowed to flow from one to another. Ventilate the roof once water vapour has entered the roof space the usual and most practical way of removing it is by ventilation. Duo pitch roofs greater than 20 0 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.

Flat roof this usually consists of felting which has a slight fall to allow rain water to drain off. Pitched roof spaces should have ventilation openings at eaves level to promote cross ventilation. Eaves to eaves roof ventilation. Roofs with a pitch of 15 or more.

In many pitched roofs a ventilation slot is built in along two opposite eaves so that air can flow across the roof space. Isbn 978 1 85946 679 7 pdf 683kb this file may not be suitable for users of assistive technology. Ventilation 2010 edition incorporating 2010 and 2013 amendments ref. To comply with approved document c and bs 5250 crossflow ventilation should be provided at both the eaves and or ridge level.