Ravenscar House Museum: Warm Roof, Tanking & Waterproofing Solutions

Product used: Nuratherm PIR, Nuraply 3PT/3PTM, Nuraply 3PG, Nuraply 3PM

Architect: Patterson Associates

Developer: HRS Construction

Situation

Ravenscar House Museum was built to house the art collection of Christchurch philanthropists Jim and Dr Susan Wakefield after their original Scarborough home was lost in the 2011 Canterbury earthquakes. Gifted to the people of Christchurch and operated by Canterbury Museum since opening in 2021, the building provides a permanent home for an internationally significant collection.

The design reinterprets the layout of the Wakefields' original home, with four gallery spaces arranged around a central courtyard and reflective pond. Distinctive gabled forms reference neighbouring heritage buildings, while the precast concrete walls incorporate crushed masonry recovered from Christchurch's earthquake-damaged buildings, embedding the city's history into the fabric of the museum.

Protecting the valuable collection required a building envelope capable of delivering exceptional long-term waterproofing, thermal performance, and durability.

Challenge

Ravenscar House Museum presented a complex waterproofing challenge, with three distinct areas requiring integrated solutions: below-ground tanking, the warm roof system, and the podium waterproofing.

The building is supported on seismic base isolators, requiring a waterproofing system suitable for below-grade slabs, foundations, and retaining walls. Above ground, the galleries required a high-performance warm roof that would provide continuous insulation while maintaining stable internal temperatures and reducing the risk of interstitial condensation.

The roof design also featured a rainscreen of concrete tiles with bespoke edge detailing. The waterproofing membrane needed to remain fully protected while allowing the tiles to be removed for maintenance without penetrating the membrane. Around the podium, a ballasted margin required a robust waterproofing solution capable of resisting root penetration and providing long-term durability.

Solution

Nuralite worked closely with Patterson Associates throughout the developed design phase to provide a complete waterproofing solution across all three areas of the building.

The below-ground structure was protected using the Nuraply 3PT/3PTM tanking system, specified for the foundations, retaining walls, and below-grade slab to provide reliable waterproofing around the building's base-isolated structure.

The roof was constructed as a Nuratherm PIR warm roof finished with the Nuraply 3PM membrane. Positioning the PIR insulation above the structure creates a continuous thermal envelope, improving energy efficiency while significantly reducing the risk of interstitial condensation. This was particularly important for maintaining stable environmental conditions within the museum galleries.

Working alongside Patterson Associates and the structural engineer, Nuralite contributed to the development of a project-specific edge detail for the concrete tile rainscreen. Based on a standard Nuralite detail, the final solution eliminated the need for top fixings through the membrane, preserving the integrity of the waterproofing system while allowing individual tiles to be removed and replaced for future maintenance.

The podium perimeter was waterproofed using Nuraply 3PG, a root-resistant membrane designed to provide durable protection beneath the ballasted margin.

By delivering a complete waterproofing specification backed by a single 20-year material defect warranty and supported by CodeMark-certified membrane systems, Nuralite simplified project coordination while providing long-term confidence in the performance of the building envelope. The result is a robust, integrated waterproofing solution that helps protect one of Christchurch's most important cultural assets and preserves the valuable collection it houses for generations to come.

3 September 2026