Wai Ariki, meaning ‘chiefly waters’, is a luxury spa based on the shores of Lake Rotorua. Developed and owned by Pukeroa Lakefront Holdings Limited, the space brings Te Ao Māori to the fore, offering traditional practices and harnessing the benefits of the site’s geothermal waters long recognised by the elders of the iwi as having innate healing properties.

The geothermal nature of the site also brought about key challenges for construction, with architects RCG needing to find smart solutions for tanking and waterproofing. Having worked with ARDEX successfully in the past, they turned to the ARDEX team again to specify trusted and compatible waterproofing and tiling systems that would ensure longevity for Wai Ariki.

Gas proof membrane for long-lasting protection of concrete

One of the key challenges of the project was ensuring the building and foundations would endure the corrosive nature of the Rotorua site. “The site sits on an active geothermal field,” explains Alex Liang, Associate Director - Architect, RCG. “Specification of the gas proof membrane below the floor slab was of immense importance as it needed to stop the corrosive sulphur gas and water in the ground from attacking the concrete.”

The ARDEX team recommended their ARDEX WPM 1500 — a specialist tanking and gas barrier membrane that is made here in New Zealand and designed and tested specifically for our geothermal regions. “It’s widely used in Rotorua which gave us confidence that it would work,” says Alex.

Waterproofing specialists, Holmac NZ Limited, installed the ARDEX WPM 1500 membrane across the 7000m² site. Pressure testing of the joint was then undertaken to ensure there were no leaks, providing confidence that the installation is 100% airtight.

Smart waterproofing and tiling for the spa’s extensive wet areas

With geothermal pools being central to Wai Ariki’s spa experience, the RCG team had a big task on their hands to ensure effective waterproofing of wet areas and tiling throughout.

Over 3000m² of tiling was installed by The Tile People, with ARDEX systems specified including ARDEX WPM 002 — a liquid waterproofing membrane which was used for floors, floor channels, swimming pools and shower areas; ARDEX X10 — a tile adhesive used for tiled walls; and ARDEX X18, an extremely strong fibre reinforced tile adhesive that was ideal for steam rooms.

“Designing pools will always have its complexities,” says Alex. “We relied on ARDEX to provide the solution for waterproofing the floors, tiling adhesives, and grouts as one system. Doing it this way we had confidence the products would be compatible with each other.”

Particular care was taken to ensure products chosen would fit with the sophisticated design of the spa. One example of this is the use of ARDEX EG 15 high performance Epoxy Grout for the glass mosaics within pools; the grout does not discolour after prolonged contact with pool chemicals, ensuring the finished design of the pools is maintained long term.

Waterproofing and sealant to keep precast concrete panels pristine

The exterior of the building features precast concrete panels which provide the durability needed in the harsh geothermal environment. To enhance the look and longevity of the precast concrete, ARDEX RA030 was used between panel joints to provide a waterproof seal, while ARDEX WPM 163 — a clear sealer with a matt finish — was applied to panel faces to not only provide a waterproof seal but also keep the panels looking consistent no matter the weather.

Backed by expert service and a system warranty

Throughout the construction of Wai Ariki, durability and longevity were key to meeting the clients' brief for a facility that would last for generations to come. By becoming involved early in the project, ARDEX were able to work side by side with RCG to supply a compatible system of products backed by a System ARDEX Warranty.

“Specifying ARDEX products with their all-embracing warranties gave us confidence that the products would work and that they would stand behind their product and service,” says Alex. “ARDEX also provides fantastic technical support to architects and contractors which made it easy to work with them. This is a critical aspect when it comes to designing a complex project such as this.”

A one-of-a-kind building, designed to last

Opened in June 2023, Wai Ariki is an exciting new development for Rotorua that is set to provide opportunities in the region for generations, and a huge achievement for Pukeroa Lakefront Holdings Limited, RCG, and all parties involved.

“Wai Ariki is not only the most significant spa development in Aotearoa for more than 100 years, it is one of only a handful of indigenous-owned operations in the world,” says Alex. “For an architect, designing a spa complex like Wai Ariki Spa is a once in a lifetime opportunity and we are grateful for what we have achieved together with our client.”