The roof system reducing condensation in New Zealand buildings

As weather intensifies and building performance requirements become more demanding, the way a roof is constructed has become increasingly important. No longer is it only colour, profile and material being considered; how the roof is assembled, insulated and managed for moisture ultimately determines the performance of the entire building.

It’s why the Dimond Advanced Roofing System (DARS) was developed. Determined to improve this protective layer of our buildings, Dimond Roofing set out to solve two key challenges facing the New Zealand construction industry: the ongoing risk of condensation and mould within building envelopes, and the increased insulation requirements introduced through updated Building Code thermal performance standards. 

“Dimond has been providing warm roof solutions for more than eight years and has seen growing demand for solutions that improve thermal efficiency while simplifying compliance. By relocating the insulation directly beneath the roof cladding and creating a warm roof construction, DARS moves the dew point outside the building envelope, significantly reducing the potential for condensation,” says Dimond Roofing’s Lead Specification Manager, Stacey Nickel. 

At the same time, it provides an efficient way to achieve higher R-values while maintaining the aesthetic appeal, design flexibility and proven performance of long-run metal roofing systems.

Developing the system

Getting to this stage was a process of feedback and consultation with those who use and specify Dimond’s products, including architects, builders and roofing installers. 

Dimond had already been offering a warm roof solution through Tricore since 2018, but there was room for improvement. While it delivered strong thermal performance, feedback highlighted the need for greater flexibility to suit a wider range of project types and design requirements. 

The introduction of the H1 Building Code updates in 2021 added another consideration. With higher insulation requirements, there was demand for a more adaptable solution that could easily achieve increased R-values. 

All of this played into the design of DARS: a fully enclosed warm roof construction that minimises the movement of air and moisture through the roof assembly.

A complete, warm roof build-up

Taking a systems-based approach simplifies the design, specification and procurement process while providing greater confidence that all components will work together as intended. Rather than selecting and coordinating roofing, insulation, vapour control and associated components individually, architects can specify DARS as a complete, engineered solution that has been designed, tested and certified to deliver the required thermal, weather tightness and condensation-management performance.

“The system incorporates full perimeter flashings, creating a sealed environment that prevents external air from entering the roof build-up and eliminates the need for traditional roof cavity ventilation,” says Stacey. 

All DARS configurations include a dedicated vapour control layer and roofing underlay, ensuring moisture generated within the building is managed effectively, helping reduce condensation risk while providing reliable thermal performance. By having the insulation positioned outside the structural roof deck and the roof build-up fully sealed, ventilation isn’t needed within the system and it doesn’t matter what climate the system is installed in.

The system also allows buildings to be made weather-tight earlier in the construction process, something that’s particularly valuable on larger commercial, industrial and education projects where programme certainty and construction efficiency are critical.  

“Feedback on DARS has been overwhelmingly positive across architects, builders and roofing contractors. Architects appreciate the simplicity of specifying a complete, CodeMark-certified roofing solution with a comprehensive 20-year system warranty, and often comment that the design process is easier than initially expected, and contractors value the system’s straightforward installation process, quality assurance framework and ongoing technical support.”

When DARS is specified, the focus shifts from installing individual roofing components to delivering a complete, quality-assured roofing system. Architects have greater flexibility with multiple warm roof build-up options, each with a range of insulation and component choices to suit different project requirements, and designers can balance thermal performance, condensation control, structural requirements, budget considerations and buildability without compromising their design intent. 

Learn more about DARS and see how other professionals have used it for their projects on ArchiPro.