Warm & Dry at Rangiora West Primary School

Warm & Dry at Rangiora West Primary School with Tricore®

Dimond’s Tricore® three-layer insulated roof system was specified for the Rangiora West Primary School, a new build in a region known for temperature extremes. Ministry of Education requirements for this project demanded warm roof technology and advanced moisture management.


Keeping students comfortable in all seasons

Rangiora holds the record for New Zealand’s hottest daytime temperature of 42.4°C, recorded in 1973. In winter, it’s not uncommon for the area to register temperatures below zero. But for the students beneath the roofs of Rangiora West Primary School, extreme heat and cold are relegated to outside, not inside.

Weathertightness and warm roof requirements pointed to Tricore®

To conform with the Ministry of Education’s (MOE) weathertightness design requirements for new school buildings, particularly the preference for ‘warm roofs’, Southbase Construction specified Dimond’s Tricore®. Newfield Roofing, a highly respected family-owned business that often works on education projects, installed the system. Angela Duthie, Specification Manager for Dimond Roofing, explains why Tricore® was chosen for this project:

“In the past, roof insulation was installed at ceiling height. But best practice has rigid PIR insulation installed at roof height, directly under the roofing profile. PIR takes up much less space than traditional insulation, for example, 80mm thickness of PIR achieves R3.6. To get the same R-value with glasswool insulation, you’d be looking at 165 to 180mm thickness.”

Advanced moisture control to manage the effects of night sky radiation

In addition to supporting the MOE’s warm roof requirements, the Tricore® system assists with moisture control. The slotted roof rail design allows passive air movement under the roofing profile to manage moisture, which can manifest after sunset due to a phenomenon called night sky radiation, this results in lower moisture and humidity levels in the system.

Another Tricore® benefit for budget and time-sensitive projects is the ability to close in a building quickly. Alex Newfield of Newfield Roofing explains:

“Tricore® goes on quickly. We were able to roof an entire classroom block in one morning. And because the roof is closed in as soon as we’ve installed the steel lining sheet, other trades can get going.”

The Tricore® system also allows the ability to replace the outer profile layer quickly and easily, especially important for buildings that require longevity, such as primary schools.

“The galvanised roof rails are fixed through the insulation to the purlins, then any of the Dimond roof profiles can be fixed onto the rails. It means the profile can be changed without upsetting the insulation. For lifecycle costs, it’s the best system an education facility can have,” says Angela Duthie.

A proven system supported by a strong warranty

For the Rangiora West Primary School project, Dimond Roofing supplied all roofing components – liner tray, PIR insulation, roof underlay, galvanised roof rail, and roofing profile, along with flashings and fasteners. Dimond have done their homework with the Tricore insulated roof system and provide a 15-year warranty on components.

Off the back of this successful project at Rangiora West Primary School, Newfield Roofing has subsequently secured further education sector projects using the Tricore® System.

Tricore® explained

  • A base layer of NPM 900 (Based on the BB900 profile) forms the working platform for other layers. Once it’s installed, the area beneath is weatherproof.
  • The insulation layer is Enertherm PIR, a highly efficient thermal insulation and acoustic performance material that delivers consistent R-values and can reduce noise levels within the building.
  • Solitex Mento 1000 is the underlay layer. It’s a non-wicking building paper that allows vapour to permeate to the cold side of the roof.
  • A slotted roof rail system provides ventilation that allows moisture to evaporate.
  • The exterior surface can be finished in any roofing profile from the Dimond® range. The life cycle of the roof can be extended by replacing only this top profile, not the entire system.