Roof Space Ventilation Requirements

For example in the average house with a cold loft there should be a minimum of a 7mm continuous ventilation gap at eaves when using a vapour permeable underlay with a normal unsealed ceiling.

Roof space ventilation requirements.

In order to facilitate this exchange of warm and cool air the general rule of thumb suggests installing at least 1 sq. You can also contact your local municipality to check on building code in your area. Ventilation at the eaves. If your roof is 1200 sq ft soffit floor space you will need 4 sq feet of roof ventilation.

According to their requirements you should have 1 square foot of attic ventilation per 300 sq ft of attic floor space. Of vent for every 300 sq. Most building codes require a ratio of 1 150 ventilation space to attic floor space. 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.

This pk topic provides commonly accepted ventilation practices compatible with a decra roof system installation. Ventilation of attic spaces is required by most building codes as well as by roofing material manufacturers and the national roofing contractors association nrca. Roof vents choose one of the following products to meet the recommended exhaust nfva of 528 square inches. Duo pitch roofs greater than 200 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.

With the many well documented benefits of dry fix systems it also makes perfect. Bs 5250 sets out the minimum requirements for roof space ventilation. Ventsure 4 foot strip heat moisture ridge vent 27 lineal feet required. Roof voids must be ventilated in order to stop warm air condensing on cold surfaces.

Typically building codes include minimum attic space ventilation requirements as well as the roofing industry weighing in on practical guidelines. Proper attic area ventilation is an important performance consideration for a home or building with a steep slope roof. The air gap dimensions shown on the drawings are the minimum widths required for clear continuous ventilation air paths at the eaves. There should also be a 50 50 balance of attic venting and roof venting.

The key to proper ventilation of your roof and attic is balance.