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VENT Cold Roof Pitch >30° Ventilation System

Through the design and installation of specific product combinations, an unimpeded passive ventilation system is created.

For a Cold Roof Pitch of above 30° the following product combinations are recommended:

  • G1200N VENT Over Fascia Vent
  • G502 VENT Roll Panel Vent
  • RV10P VENT Ridge Vent (for long run metal roofs)

A Cold Roof Pitch greater than 30° degrees requires continuous cross airflow of 10.000mm² per lin/m at eaves level and ventilation at the ridge of the roof. Ventilating the roof cavity in this way will ensure that internal moisture is greatly reduced in the roof cavity which safeguards the roof from damp, mould and structural decay.

Key Features
  • Creates negative pressure to ensure air flows in and out of the roof cavity
  • Eradicates condensation in the roof cavity
  • Allows calculated airflow into the roof space
  • Allows moisture escape
  • Reduces the temperature above the thermal envelope of the building
  • Protects the insulation from moisture transfer and wind movement
  • Ensures 25mm gap between insulation and roofing underlay
  • Reduces margin for error during insulation installation process
  • Prevents ingress of nesting insects into the roof cavity
  • Easy to install
Scope of Use

These passive ventilation systems can be applied to all building types in all areas.

VENT's passive ventilation roofing systems allow a calculated amount of fresh air to enter the roof cavity.  

As part of the VENT passive ventilation roofing system, the VENT Roll Panel Vent (G502)  ensures a 25mm gap is maintained between rigid or flexible roof underlays and insulation to avoid moisture transfer and air disturbance, to meet the requirements of most insulation products.

Vent passive ventilation systems can be used with roof types such as long run, pressed metal, asphalt shingle and concrete tiles.

The system also works well with mechanical ventilation systems that are not externally ventilated i.e they do not ventilate from outside the building but from inside the roof cavity.

Limitations on Use

VENT's passive ventilation roofing systems and products focus on the ventilation of roof spaces only, determined by the pitch of the roof. 

The VENT Ridge Vent (RV10P) is only compatible with long run metal roofs

Statement of Building Code Compliance

VENT's Passive Roof Ventilation Products comply with the following provisions of the NZ Building Code:

  • B1.3.1, B1.3.2
  • B1.3.3 (a)
  • B1.3.4 (a, b, c, d, e)
  • B2.3.1 (a)
  • B2.3.2 (a)

Evidence: All products are manufactured by Manthorpe Building Products Ltd (UK) who are ISO 9001 accredited by SGS Certificate # GB12/84769, certified since 2011.

In-Service History

Passive Ventilation has been used in Canada, America, the United Kingdom and Europe for almost four decades. By introducing passive ventilation into roofs these countries have significantly reduced internal moisture and prevented what was called 'sick home syndrome'.

More recently in New Zealand, since changes to E3:AS1 1.1.4.b of the New Zealand Building Code in 2014, passive ventilation has become more widely understood and the need to ventilate the uninhabited spaces in a building has been more widely acknowledged. Industry experts BRANZ have endorsed passive ventilation as a necessity in skillion roof types and have recommended that all roof types are passively ventilated as redundancy to eradicate internal moisture.

The NZMRM is currently revising the Metal Roofing Code of Practice to incorporate ventilation into certain roof design and strongly recommending passive ventilation in all metal roof types.

Since the amendment of E3:AS1 hundreds of New Zealand buildings have incorporated passive ventilation into building design and application. These buildings include MOE school re-roof projects, residential new builds and renovations, and commercial projects.

Data Sheet: Roll Panel Vent G502


Passive Ventilation System: Roof Pitch >30°


BRANZ Appraisal 979


Maintenance and Warranty




Video: Why Is Passive Roof Ventilation Necessary


CAD/PDF Details
Full Set of drawings with Final Extra Batten

Full Set of drawings with Final Extra Batten


Full Set of Roof Drawings

Full Set of Roof Drawings


VENT Roll Panel Vent - G502

VENT Roll Panel Vent - G502


VENT provide complete passive ventilation systems that ensure healthy homes free from internal moisture and condensation.

Product Enquiries

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