Orkney Roofing was selected by the Wellington City Council for the reroofing of the Newtown Library on Constable Street. The Newtown Library, built in 1989, originally featured a pressed tile roof that had become a persistent source of leaks. Numerous problematic details, now non-compliant with current building codes, were identified, particularly where the low-pitch membrane roof intersected with the pitched roof. The office section of the library, covered with a Butynol membrane over plywood, had experienced numerous patch repairs over the years. Eventually, the membrane failed entirely, leading to flooding and rendering the offices unusable due to a rotten ply substrate.

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The Solution

The project involved a comprehensive reroof, transitioning from the original tiles to Corrugated Colorsteel Maxx in Grey Friars. This required re-framing the roof with new purlins and installing R3.2 Skillion insulation. The risky details were meticulously addressed by installing undersized valleys with a new substrate, TPO valleys, TPO secret gutters, and new flashings for the large atrium skylight. Additionally, the capacity of the secret gutters at the building’s intersection with neighbouring structures was increased.

 

For the office roof, a shrink-wrap scaffold was erected to protect the area during work. The existing membrane was removed, and a new plywood substrate was installed. The building work included enhancing the structural support for the substrate and adding vented battens to promote air movement within the cavity. Viking Enviroclad TPO was used as the waterproofing membrane including vents ensuring effective cavity ventilation.​

 

The Results

The project delivered a high-performance, waterproof roofing system for the office spaces and significantly reduced risks in critical areas through increased capacity and improved structural details.