In 2016, the old presbytery and office next to St. Patrick’s Church were demolished due to the prohibitive costs of seismic compliance. This made it essential for the Catholic Parish of Napier to build a new mission and administration centre to continue their outreach and services.

Some years earlier, a distinctive barrel vault roof had been constructed and waterproofed with Viking Enviroclad membrane on an existing building. So, the Mission Centre wanted to replicate the same roof for the new structure. It was at this point that Atkinson Harwood Architects contacted Viking Roofspec for assistance with the new design.  

The architect’s aim was to ensure the substrate was designed effectively to form the barrel dome structures for a smooth membrane installation, whilst including adequate ventilation in the cavity.

Building consent was received from the Napier City Council, a contract was signed with Atkin Construction to begin, and a Viking Approved Applicator won the tender for the Enviroclad membrane Installation.

Then the fun began...

The initial substrate design comprised of two sheets of 12mm plywood laminated together to the appropriate radius, which was signed off by an engineer. But the installation didn’t go to plan. The radius on the first layer was too tight for the 12mm ply which resulted in stress fractures to the plywood face. The decision was made to swap this out for a 9mm first layer, with a 12mm sheet installed on top. Decorative timber ribs running perpendicular to the building, were then formed by laminating layers of plywood together.

Once that challenge was overcome, the licensed installers installed the Enviroclad by dressing the membrane up each rib, making the weld on the flat top of each one, so the visual effect was the appearance of a continuous piece of membrane up and over the barrel.

Minor bubbling under the membrane soon occurred. On inspection, it turned out that the vent strips at the base of the roof had been blocked by other trades. Once unblocked, the venting operated as intended and all bubbles dissipated leaving an impeccable roof.

This project is an example of the specification hitting some construction limitations. Nonetheless all stakeholders worked coherently to find a practical, compliant resolution. Just knowing when to seek assistance, and doing so before it’s too late, can save a project from failure.

Keeping the substrate dry while working in wet, winter months added to the complexity of this installation, yet the Approved Applicators installed the Enviroclad membrane on this barrel roof with results nothing less than perfect. Atkin Construction appreciated the ease with which all stakeholders worked together. They also appreciated the technical assistance when needed from the Viking team.

To top it off, this bespoke project with its curved membrane roof, was shortlisted for the 2024 Te Kāhui Whaihanga NZ Institute of Architects Local awards in the Public Architecture Category.⁠ Congratulations to all involved – especially our Approved Applicators!

Viking Enviroclad, available in seven earthy colours, wide sheets and heat-weldable splicing technology, is the ultimate watertight solution. It is CodeMark Certified and BRANZ Appraised, providing the highest form of product assurance in the industry, but most importantly (seeing construction materials are only as effective as their installation), Viking materials are only supplied and installed via Viking’s network of Approved Application companies whose installers are licensed at Viking’s training facility. This maximises the level of workmanship with Viking's membrane systems.