Pitched Roof Eaves Ventilation

Eaves with over fascia ventilation.

Pitched roof eaves ventilation.

When using vapour permeable roof underlays in a pitched cold roof is it necessary to provide ventilation trays at the eaves. Where high water vapour resistant type hr underlay e g. Manthorpe g1275 eaves comb filler pack of 50. Eaves soffits and fascias.

The air gap dimensions shown on the drawings are the minimum widths required for clear continuous ventilation air paths at the eaves. The roof is covered with high water vapour resistant type hr underlay and the pitch exceeds 35 or the span exceeds 10m this is in addition to eaves ventilation. Roofs with a pitch of 15 or more. To provide ventilation opening points can usually be provided on the following areas of a pitched roof.

If the roof covering or roof membrane is a material of high moisture resistance or impermeable then the building regulations require a 50mm wide ventilation gap. Set top of fascia board at correct level and fit ventilator in accordance with manufacturers recommendations. The requirements will be met by the ventilation of those roofs where the moisture from the building can pass through the insulation. Types 1f 5u felts is used eaves ventilation should be provided on opposite sides of the roof to permit cross.

Eaves ventilation is a simple and effective way of providing the necessary air movement within a cold roof. If a sprocketted or bell cast detail is used then eaves courses should beno lower than the minimum recommended roof pitch. Pitched roof spaces should have ventilation openings at eaves level to promote cross ventilation. Eaves courses of tiles should be at same pitch as general tiling.

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. Vent the roof deck. We stock a wide range of pitched roof vents and roof ventilation products from leading brands such as ubbink marley eternit redland. Slating and tiling for pitched roofs and vertical cladding code of practice recommends that roof ventilation be provided in accordance with bs 5250.

It is most effective when used in conjunction with high level roof ventilation provided by corovent slate tile and ridge vents. Nhbc standards clause 7 2 14 requires that where a vapour permeable underlay vpu is used in a cold pitched roof the roof should be ventilated at ridge or high level. Timloc 3 in 1 eaves ventilation pack 10mm airflow 300mm rafter tray 13 86 ex vat 16 63 inc vat.