Soudal Products Take Centre Stage At New Waikato Regional Theatre

The Waikato Regional Theatre (WRT) promises to be a world-class performing arts centre that will transform Hamilton’s CBD into a thriving creative arts and entertainment destination.

The multipurpose venue features a 1300-seat auditorium with grand circle balconies and will be capable of hosting everything from ballet to kapa haka, music gigs, drama, musical theatre, stand-up comedy and so much more when it opens in late 2025.

Soudal’s sealants and foams are used throughout the $80m project, providing unique solutions and a level of performance that rival products are unable to match.

WRT is designed by acclaimed international theatre architects, Charcoalblue, in partnership with New Zealand’s own Jasmax, and sits beside the Waikato River at the south end of Victoria St where the historic Hamilton Hotel once stood. The old hotel’s French ‘Beaux Arts’ façade has been retained, and an entirely new multi-story building has been constructed featuring locally-quarried Hinuera stone, extensive glazing and pre-cast concrete panels.

Foster Construction is the lead contractor and Cantec Services Hamilton Ltd has expertly applied all sealants. Soudal worked closely with all parties to supply products that meet the exact specifications – sourcing samples and technical data from across the globe to prove their sealants and foams meet the flexibility, durability and acoustic value required.

Flexible focus

Cantec supervisor and lead applicator, Delane Mareroa, says over 2000 lineal metres of Gorilla MS Sealant has been used to provide a durable and weather-tight seal on all concrete tilt slab joints, and overfill holes used to pin together Hinuera stone on several exterior and interior blade walls.

Joint flexibility was the key criteria in choosing this sealant because WRT is built between a riverbank and busy road, and features disparate materials including the historic façade.

Engineering specifications demanded a sealant that had plus or minus 50% movement of the joint width (ASTM C9 20 class 50% movement). Gorilla MS Sealant was one of the only products readily available in New Zealand that could deliver that movement capability, with Soudal providing testing data from their headquarters in Belgium to gain the tick of approval from Jasmax.

White Gorilla MS sealant has predominantly been used as it’s easily paintable, but Cantec will apply a black version to the theatre’s fly tower. “I much prefer Soudal’s black sealant over competitors’ products,” Delane explains. “I’ve had black sealants before where the pigment gets everywhere. But the Soudal product doesn’t transfer and cleans up a lot better. All their products are easy to apply and finish nicely. They’ve got a good work time. If it’s a windy day then they skin up a bit quicker but I’ve got no problems with it. I like using them.”

Delane also values Soudal’s customer service. “I can ring with any questions and get an immediate answer so work isn’t held up. I haven’t had that level of service or communication before. We’ve got a good relationship. Their delivery timeframes are good too. We typically have about 10 boxes on-site, and when we get down to five, we can usually pick more up straight away.”

Stone solution

Soudal drew on its worldwide network to source a flexible sealant that was compatible with, and could be coloured matched to, Hineura stone. Multibond SMX25 was eventually chosen by Jasmax and Foster Construction after Soudal provided multiple samples from Australia and Belgium.

This product is not normally available in New Zealand but has been used to seal 6mm gaps between each stone panel on the blade walls. It offers 25% flexibility but most importantly, it will not stain natural stone (a common problem is that a black shadow can develop around the stone’s edges after several years if a sealant reacts with the porous surface).

Foster Construction Quantity Surveyor, Mark Shaw, says the architect’s aim was to create large monolithic walls that read as a solid piece of structure. “As not all the panel joints are sealed, it was crucial to have a close colour match so that the panel joints that are sealed don’t stand out compared to the ones that aren’t.”

The sealant’s anti-stain properties were also crucial as the potential appearance of ‘wet look’ lines around the stone edges was not something that could be entertained.

Problem-solving expertise

Soudal’s Technical Manager, Steve Loveridge, went the extra mile by helping design a grid bracket system to hold each stone panel in place. At Steve’s suggestion, the depth and position of the holes and pins were adjusted to provide much greater strength and movement capability.

“If we see things that aren’t going to optimise the use of our sealants to achieve function, we will try and work with the engineers and the installers to find a way to do the job that optimises outcomes for everyone,” Steve explains. “It’s about looking for the best solution.”

Soudal also collaborated with Cantec to develop an oversized PEF rod using black pipe insulation to avoid visibility issues in the fly tower. This teamwork approach is greatly appreciated by everyone involved.

Unique benefits

Sillirub Coloured Silicone RAL8014 Walnut has been sourced from Belgium, with Soudal able to urgently import the required amount at short notice. This high grade silicone has been specifically colour matched to finish off a walnut feature wall in the public area overlooking the Waikato River.

And finally, Soudal’s innovative Flexi Foam was chosen to help boost acoustics within the theatre. It has been applied behind our other sealants and offers an acoustic value of STC 61. While this value is similar to other foams on the market, none provide the flexibility that is required between WRT’s construction joints. As the concrete panels expand and contract, standard polyurethane foams would simply disintegrate over time. But Flexi Foam will move with the building, providing the ideal solution. It has a much tighter cell structure than standard foams with a 30-40% post expansion rate, so applicators can be far more accurate and waste less product when gunning it out.

Quality control

Cantec has greatly appreciated Soudal’s destructive testing programme, where a selection of fully cured joints are pulled apart to check everything is connected properly and the products are applied at the correct depth and consistency. Those tests then form part of the final documentation when the building is handed over to the client.

“We’ve had nothing split, it’s been really good,” Delane says. “That gives me the confidence that our boys are doing the job properly, and the product that we’re delivering to the customer is going to last the distance.”

Soudal has also provided electronic and manual documentation to make it as easy as possible for Cantec to keep accurate quality control records.

First choice partner

“I’d definitely recommend Soudal,” Delane says. “It’s not only the products, but their team that backs their products.

“If you don’t have a good relationship with your key suppliers, big jobs can go south pretty quick. You need people with fast reactions who will get you the answers you need straight away. That’s why it’s important to work with people who will go that little bit further for you.”

Fosters Construction agreed Soudal were great to work with. “They had good communication and were always available when needed,” Mark says. “And they were willing to work with us and seek alternative products when required.”