Roof Void Ventilation Building Regulations

Flat roof this usually consists of felting which has a slight fall to allow rain water to drain off.

Roof void ventilation building regulations.

This should ensure that effective through ventilation of the whole roof is achieved and assist in pulling moisture laden air out of the building and limiting condensation. A roof void above an insulated ceiling. Pitch roof this is where tiles or slates are used and a void is usually created underneath. Ventilation of the existing roof void s will have to be considered as air must still be allowed to flow from one to another.

Isbn 978 1 85946 679 7 pdf 683kb this file may not be suitable for users of assistive technology. Roof space ventilation introduction building regulation approved document c2 refers to bs 5250. Roofs with a pitch of 15 or more. Sufficient cold roof ventilation.

Both building regulations and nhbc require ventilation to be provided in roof spaces. Airtrak is a proprietary range of ventilators designed specifically for the ventilation of roof voids. 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. 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.

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. A room that the rooflight is to serve will need to be ventilated. Ventilation 2010 edition incorporating 2010 and 2013 amendments ref. Eaves to eaves roof ventilation.

Ventilation can be achieved by using the rooflight for both rapid and background venting. In many pitched roofs a ventilation slot is built in along two opposite eaves so that air can flow across the roof space. Ventilate the roof once water vapour has entered the roof space the usual and most practical way of removing it is by ventilation. The british standard code of practice for control of condensation in buildings as a means of compliance with a general requirement that adequate provision be made to prevent excessive condensation in a roof or roof void above an insulated ceiling.

To comply with approved document c and bs 5250 crossflow ventilation should be provided at both the eaves and or ridge level. Where the void is open eaves to eaves air flow is effective along the longer sides of the building. The requirements will be met by the ventilation of those roofs where the moisture from the building can pass through the insulation. Pitched roof spaces should have ventilation openings at eaves level to promote cross ventilation.