Roof Ventilation Regulations

Part h of the building regulations regarding drainage state that water should drain to one or two edges.

Roof ventilation regulations.

The key to proper ventilation of your roof and attic is balance. The net free vent area nfva shall not be less than 1 150 of the area of the space being vented. Warm roofs must have a vcl bonded to the deck. The amount of space you devote to intake must be equal to the amount you allow for exhaust and these must be calculated according to the size of your attic and slope of your roof.

These ventilation needs are calculated differently. The air gap dimensions shown on the drawings are the minimum widths required for clear continuous ventilation air paths at the eaves. Theinternational building code 2012 edition ibc 2012 requires enclosed attics and enclosed rafter spaces formed where ceilings are applied directly to the underside of roof framing to have cross ventilation for each separate space. Required ventilation openings shall open directly to the outside air and shall be protected to prevent the entry of birds rodents snakes and other similar creatures.

Roof voids must be ventilated in order to stop warm air condensing on cold surfaces. Condensation encourages rot and mould growth. Waterproofing should extend up the adjacent walls at least 150mm from the roof surface. R806 2 minimum vent area.

Roofs must be wind resistant and strong enough to walk on. Cold roofs must have ventilation.