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H1 Skillion Roof Solutions

H1 compliance in SKILLION ROOFs

The New Zealand building codes thermal requirements H1/AS1 applies to housing, and other buildings that are under 300 m².

In H1/AS1 there are two methods of compliance: the Schedule Method and the Calculation Method.

The Schedule Method of compliance requires roof construction R-values equal to, or in excess of R6.6 in all six climate zones. However, achieving these values for skillion roofs can be challenging due to limited rafter space. The Calculation Method allows you to reduce the R6.6 construction value, required by the Schedule Method. This reduction can be offset with higher thermal values elsewhere in the building.

Facilitate compliance with both the Schedule and Calculation Methods effortlessly with Knauf Insulation's range of products and systems.

Benefits of high-performing skillion roofs 

Achieve superior thermal performance and enhanced comfort for your building by opting for a high-performing skillion roof. By designing a skillion roof that exceeds the R6.6 requirements, detailed in the Schedule Method, you will further enhance the performance characteristics and provide flexibility when using the Calculation Method.

A skillion roof that exceeds R6.6 can be used to offset other areas of the building and make a positive contribution to H1 compliance. Make a significant positive impact on your project's energy efficiency and comfort by choosing a skillion roof that goes above and beyond expectations.

Considerations for H1 Compliance and an effective skillion roof solution

While meeting H1 Energy efficiency thermal requirements is vital, detailing an effective Skillion roof involves more factors. Ventilation and other building code requirements must be considered. The New Zealand Building Code (NZBC) requires that you maintain a 25mm separation between the roofing underlay and the insulation. While not detailed in the Building Code a 25mm airgap below the roofing Perlin is widely recognized as best practice. This practice is even mandated by certain roofing products.

Streamline your skillion roof design with Knauf Insulation's glasswool products. Our solutions are designed to do both, the product thickness is designed to match a range of standard joist depths and maintain the required air gaps. With Knauf Insulation, you can ensure your skillion roof meets ventilation requirements, building codes, and industry best practices.

Benefits of Knauf Insulation Solutions


Our skillion roof insulation batts are designed toffer a combination of excellent thermal and acoustic performance. The products are specifically designed to provide the maximum thermal contribution in the space allowed. Our systems allow for Building Code requirements to be met and ventilation requirements to be maintained. 

The addition of a 45mm R1.3 insulation batt provides additional options at the ceiling level. A combination of products in this way reduces thermal bridging and allow scope to further increase the thermal performance of the system while maintaining the selected rafter depths.

Knauf Insulation Skillion Roof batts are non-combustible, made using up to 80% recycled glass and with ECOSE® Technology, a sustainable binder with no added formaldehyde. They’re available in a range of R-Values and sizes to suit most joist spaces.


R-Value (m2K/W)
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*Specifically designed to meet the H1 Building Code changes

Skillion roof insulation for your project