Cathedral Roof Pitch Any Degree

Colourbond Cathedral Pitched Roof ≥10°

The National Construction Code 2022 Vol 1: F8D5 / ABCB Housing Provisions Standard 10.8.3 for a Cathedral Pitched Roof ≥ 10° requirement mandates “7,000mm²/lm at the eaves and 5,000mm² at high level, plus an additional 18,000mm²/m at the eaves if the roof has a cathedral ceiling.

Achieving this standard is flexible, with various solutions available depending on your roof design and construction preferences.

Our G2500N Over Fascia Vent 25mm guarantees a calculated airflow of 25,000mm²/lm, ensuring compliance effortlessly.

The RV10 range of ridge vents meets minimum NCC requirements for High-level ventilation.

For those seeking alternatives for ventilation at the eaves, consider the G1200N and VB20 Combination:

  • G1200N Over Fascia Vent 10mm: Provides calculated airflow of 11,000mm²/lm.
  • VB20 Ventilation & Drainage Batten 20mm: Offers calculated airflow of 14,500mm²/lm.

Combining these products yields a total of 25,500mm²/lm, surpassing the NCC minimum requirement of 25,000mm²/lm.

Either solution provides peace of mind for your project’s compliance needs.

 

Recommended Product Combination for Colourbond Cathedral Pitched Roof ≥10°

G2500N

Over Fascia Vent 25mm

The VENT Over Fascia Vent – G2500N is the most practical and cost-efficient method of ventilating the Eaves for cathedral roofs, and traditional roofs with pitches <15 degrees. It is easy to install, discrete and compatible with either timber or metal fascias.

  • 25,000mm²/lm of free airflow
  • Meets NCC DTS requirements
  • Releases hot air from roof voids and manages condensation
  • The only solution to ventilate builds with no eaves
  • Can be used in isolation or as part of a passive ventilation system
  • Can be used to form part of a passive ventilation system that works year round with no moving parts or energy consumption.
  • Easy to install
  • Not visible as hidden by spouting/gutter

RV10 Ridge Vent

The VENT Systems Ridge Vent is designed to release warm air from the roof void using the natural convection of rising warm air or by means of negative pressure created by wind blowing over the roof.

The RV10 has an adhesive and flexible aluminium flashing which is designed to form to roofing profiles and prevent water ingress on any pitch roof.

Recommended Application:

  • RV10P for cladding profiles with a through depth < 34mm
  • RV10DT for cladding profiles with a through depth 34mm – 38mm

 

  • 7,000mm²/lm of free airflow (per side)
  • Allows warm moist air to escape the roof cavity
  • Is highly recommended to only apply high level vents with some form of Over Fascia or Eaves ventilation.
  • Works year round with no moving parts or energy consumption.

G1200N

Over Fascia Vent 10mm

The VENT Over Fascia Vent – G1200N is the most practical and cost efficient method of ventilating the Eaves of traditional roof pitches 15°. However, for roof pitches <15° the G1200N can be used together with the VB20 batten to ensure compliance with NCC airflow requirements for roof pitches <15°.

It is easy to install, discrete and is compatible with either timber of metal fascias.

  • 11,000mm²/lm of free airflow
  • When combined with the VB20 Ventilation & Drainage Batten can achieve 25,500mm²/lm of free airflow
  • Meets NCC DTS requirements
  • Releases hot air from roof voids and manages condensation
  • Easy to install
  • Not visible as hidden by spouting/gutter
  • The only solution to ventilate builds with no eaves
  • Can be used in isolation or as part of a passive ventilation system
  • Works year round with no moving parts or energy consumption

*Note: for combinations see VENT System technical drawings

VB20

Ventilation & Drainage Batten 20mm

The VENT Roof cavity batten – VB20 is a 20mm Polypropylene Ventilation and Drainage Batten designed to facilitate 14,500mm²/lm of free airflow through a cathedral roof, between the roofing underlay and roof battens or purlins. Reducing the risk of insulation blocking these tight roof cavities.

However, for roof pitches <15°, by placing the VB20 behind the fascia it can be used together with the G1200N batten to ensure compliance with NCC airflow requirements for roof pitches <15°.

  • 14,500mm²/lm of free airflow
  • When combined with the G1200N Over Fascia Vent, can achieve 25,500mm²/lm of free airflow
  • Meets NCC DTS requirements
  • Facilitates movement of hot air through and into roof voids
  • An alternate solution to using larger Over Fascia Vents
  • Can be used in isolation or as part of a passive ventilation system
  • Works year round with no moving parts or energy consumption

* Note: for combinations see VENT System technical drawings

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