Roof Space Ventilation Building Regulations

Ventilation 2010 edition incorporating 2010 and 2013 amendments ref.

Roof space ventilation building regulations.

In many pitched roofs a ventilation slot is built in along two opposite eaves so that air can flow across the roof space. A roof void above an insulated ceiling. 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. Building codes vary.

Therefore it s important that the ventilation slots aren t blocked. As amended fitness of materials and workmanship c4. The requirements will be met by the ventilation of those roofs where the moisture from the building can pass through the insulation. The open area of a vent is sometimes listed on the roof air vent as nfva net free vent area.

Then aim for about 1 sq. The building regulations northern ireland 2000 regulation b2. Otherwise ventilation is required and this is known as a cold roof system. When ventilating a roof the air should be able to enter at one end and travel through to the other end where it can exit.

Of vent for every 300 sq. Isbn 978 1 85946 679 7 pdf 683kb this file may not be suitable for users of assistive technology. In cold climates the primary purpose of attic or roof ventilation is to maintain a cold roof temperature to control ice dams created by melting snow and to vent moisture that moves from the conditioned space to the attic ventilation acts to bypass the vapour barrier created by most roof. Both building regulations and nhbc require ventilation to be provided in roof spaces.

The building code lets you reduce that by half under some conditions but more roof ventilation is usually better. If not measure the size yourself. The roof space isn t intended to be a storage area so if you. Where the void is open eaves to eaves air flow is effective along the longer sides of the building.

2002 which deals comprehensively with the subject of condensation in dwellings. B resistance to ground moisture and weather and c5. Pitched roof spaces should have ventilation openings at eaves level to promote cross ventilation. 25mm air gap 25 000mm m ventilation applications of building regulations pitched roof ceiling and insulation horizontal open roof void building regulations state.

Roof space ventilation introduction building regulation approved document c2 refers to bs 5250. Throughout the balance of this digest the terms attic and roof will and can be used interchangeably. Swish ventilators also meet the recommendations bs 5250.