Roof Space Ventilation Requirements

Most building codes require a ratio of 1 150 ventilation space to attic floor space.

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. Typically building codes include minimum attic space ventilation requirements as well as the roofing industry weighing in on practical guidelines. Bs 5250 sets out the minimum requirements for roof space ventilation. Ventilation at the eaves.

Ventsure 4 foot strip heat moisture ridge vent 27 lineal feet required. According to their requirements you should have 1 square foot of attic ventilation per 300 sq ft of attic floor space. This pk topic provides commonly accepted ventilation practices compatible with a decra roof system installation. 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.

There should also be a 50 50 balance of attic venting and roof venting. With the many well documented benefits of dry fix systems it also makes perfect. You can also contact your local municipality to check on building code in your area. According to the national roofing contractors association nrca a power vent with an airflow rate of 1 0 cubic foot per minute per square foot of attic space measured at the attic floor is generally considered to be equivalent to a 1 150 ventilation ratio.

Roof voids must be ventilated in order to stop warm air condensing on cold surfaces. Ventilation of attic spaces is required by most building codes as well as by roofing material manufacturers and the national roofing contractors association nrca. The air gap dimensions shown on the drawings are the minimum widths required for clear continuous ventilation air paths at the eaves. Building codes vary.

Proper attic area ventilation is an important performance consideration for a home or building with a steep slope roof. Of vent for every 300 sq. Roof vents choose one of the following products to meet the recommended exhaust nfva of 528 square inches. Condensation encourages rot and mould growth.

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.