NCC 2022 Volume Two 10.8.3 — Calculator

Calculates roof space ventilation requirements for buildings in Climate Zones 6, 7 & 8

Click to see applicable climate zones ▼
NCC applicable climate zones map
1

Roof Space Ventilation

Enter the roof dimensions below to calculate the required open areas for compliant installations in applicable zones.

Longest horizontal dimension of the roof.
See Calculation Table ▾

Table 10.8.3 Roof space ventilation requirements

Roof pitch Ventilation openings
< 10°25,000 mm²/m provided at each of two opposing ends
≥ 10° and < 15°25,000 mm²/m provided at the eaves and 5,000 mm²/m at high level
≥ 15° and < 75°7,000 mm²/m provided at the eaves and 5,000 mm²/m at high level, plus an additional 18,000 mm²/m at the eaves if the roof has a cathedral ceiling

Table Notes

1. Ventilation openings are specified as a minimum free open area per metre length of the longest horizontal dimension of the roof.

2. For the purposes of this Table, high level openings are openings provided at the ridge or not more than 900 mm below the ridge or highest point of the roof space, measured vertically.

Select From Products Recommended For This Job

Based on your answers above, these are the product types and indicative quantities suited to this job.
Complete the section above to see your recommendations.
This tool provides a guide only based on NCC 2022 Volume Two, Part 10.8.3. It does not replace advice from a licensed building practitioner, designer or certifier. Always confirm requirements against the version of the NCC and any state/territory variations applicable to your project.