Staged Roof Renewal at Kaitaia Hospital: Correcting Falls with Tapered Insulation

4 hours ago

2 min read

Products used: Nuraply Tapered Board system with Nuraply TPO

Kaitaia Hospital is a multi-building facility serving the Far North. Several of its flat roofs had reached end of life serviceability, prompting a staged renewal program using Nuralite's Nuratherm Tapered Board system and Nuraply TPO membrane.

Situation

The hospital campus comprises several buildings with existing flat roofs constructed at differing times from as far back as the 1960’s to 2000’s and to varying original standards. As part of a broader renewal program, it was identified that the existing membrane roofing had reached its “end of life” condition and required replacing. Nuralite worked with Respond Architects to incorporate Nuralite's Nuratherm Tapered Board system to increase roof falls and performance. The works were scoped in stages to allow the hospital to remain fully operational throughout, with all areas having to remain active at all times.

Challenge

Existing falls across several roofs measured between 0.5 and 1 degree, and although the roof had been performing there were areas where water pooled on the surface, increasing the risk of ponding, membrane degradation, and long-term leakage.

One roof presented a more complex problem: the roof drained toward an internal gutter, which carried a higher risk of water ingress if a blockage or failure occurs. Redirecting drainage to external gutters was the safer long-term solution but required reversing the direction of fall entirely rather than simply increasing it.

Solution

The Nuratherm Tapered PIR Board system was installed directly over the existing roofing substrates, removing the need to strip or replace the existing construction and keeping disruption to hospital operations to a minimum.

Stage 1 covered the Theatres and Kitchen block, where tapered boards were laid over an existing plywood substrate and its liquid waterproofing membrane, increasing falls by one degree without interrupting hospital operations. Stage 2 applied the same system over a concrete substrate elsewhere on site, demonstrating the system's compatibility across differing roof constructions.

On Stage 4 for the Maternity Ward (works yet to be completed) a full reversal of fall direction was required. Tapered boards were double stacked at the location of the original internal gutter, creating a new high point in the roof profile. This redirected water toward external outlets without requiring structural alterations to the building. Nuraply TPO membrane was applied over the tapered board system to complete the waterproofing layer.

Falls across the treated areas were increased by a minimum of one degree, correcting any drainage shortfalls in the original roof design. The double-stacked configuration successfully reversed drainage direction, eliminating the internal gutter risk. All facilities have remained fully operational throughout. Stages 2 & 3 are in progress with stages4, 5 and 6 yet to be completed. Through close collaboration between Respond Architects, Brosnan Construction, and SubZero Waterproofing, Nuralite has delivered improved drainage performance, and long-term waterproofing reliability suited to a working hospital environment.

29th October 2026