Cost Conscious Tanking Solutions

[Shane Clarke] My name is Shane Clarke. I'm the General Manager here at Nuralite Waterproofing, New Zealand’s leading waterproof membrane supplier. I'm here today with Peter Mills, our Technical Adviser, and today's topic is around cost-conscious tanking solutions. Sorry, excuse me. Right, so yeah, today's topic is cost-conscious below-ground tanking solutions without compromising quality or performance. This webinar follows the same structure as the previous 43 we've done, which are all available on our website. This session runs for about 30 minutes. It's worth exactly five NZIA CPD points, and towards the end we will have a Q&A. There’ll be a survey that pops up at the end, so don’t leave immediately. If you wait a minute or two, the survey will appear and you can get your points there. So today’s key message is about how we can still achieve a high-performance tanking solution at a common-sense price point. We’re talking about that Goldilocks zone. Today Peter and I are going to cover what we define as tanking, what it includes, and how we select the right system. We’ll also include a case study that highlights time and cost savings achieved by engaging with the designer early. Then we’ll finish up with a live demonstration. We really appreciate your feedback on these webinars, and last time the live demo went down well, so we’ve got another mock-up to show how tanking works. As mentioned, there will be a Q&A at the end, so feel free to put your questions into the Q&A section. If we don’t get through everything, that’s okay—they’ll be included in the transcript sent to all attendees. So that’s us. That’s the webinar. Let’s kick off with a quick poll. On a scale of 1 to 10, how important is tanking in a building? We’ll let that run for a few seconds. So yeah, most of us think it’s quite high on the list. We would consider it a 10 for the types of buildings we’re involved with. [Peter Mills] The other reason we consider it a 10 is that you really only get one shot at your tanking. Remedial tanking is not fun or economical. [Shane Clarke] Right, we’ll kick into the presentation. Thanks Jin. Hey Peter, how are you going? [Peter Mills] Yeah, I’m good. I think I’ll start by explaining what tanking is, the main approaches, and the levels of tanking. To start off with, what is tanking? The British definition is a system of below-ground waterproofing. More than that, it’s a system that has to withstand constant water pressure. It’s very different to roofing waterproofing, where you might just have rain or some standing water. Tanking often has constant pressure trying to force its way into the structure. The goal is to keep the structure dry and prevent water from entering and causing damage. [Shane Clarke] Cool. [Peter Mills] So by our definition, there are a few things we’re looking for. It has to protect against water, it has to last in the conditions—whether that’s something like Rotorua with volcanic soils or gases—and it needs to be robust. You’ve got steel going in, other trades interacting with the system, so it has to withstand that. It also needs to be repairable if something goes wrong. And finally, it should be an integrated solution, not just waterproofing but also insulation. [Shane Clarke] Nice. We’ll touch more on that later. Let’s move to the next slide. [Peter Mills] There are a few approaches to tanking. From left to right, you’ve got internal waterproofing systems like coatings or wet wall systems, where the structure can still get wet but it’s managed so it doesn’t damage the building contents. Then you’ve got concrete additives—things like Xypex—where chemicals are added to the concrete before pouring to help prevent water ingress. Then there are unbonded membranes, which are sheet systems installed externally and rely on pressure to stay in place. And finally, our preferred option is fully bonded membranes, which are adhered to the structure so they remain intact even if site conditions change. [Shane Clarke] Cool. Before we move on, let’s run another poll—what’s your preferred approach to tanking? Don’t let our preference bias you. [Peter Mills] And if you’re unsure, that’s fine too. That’s why we’re here. [Shane Clarke] Interesting results there. Alright, next slide. [Peter Mills] We look at three levels of protection. The most basic is damp proofing, where you’re dealing with moisture rather than water ingress. Then there’s waterproofing, where the structure interacts with the water table or there’s flood risk, so you’re tanking walls and floors. Finally, there’s watertight systems for high-risk situations like reclaimed land or deep basements, where there’s constant hydrostatic pressure. [Shane Clarke] Nice. [Peter Mills] Here’s an example of a fully bonded positive-side waterproofing system. This is our Neuroply 3PT and 3PTM system. 3PT is post-applied to concrete, while 3PTM is pre-applied. There’s also a backfill protection sheet for robustness and drainage. [Shane Clarke] And the next system? [Peter Mills] This is Bituthene 3000, a self-adhesive membrane. It’s post-applied, but unlike the previous system, there’s no flame application. [Shane Clarke] And by post-applied, we mean after the concrete is in place. [Peter Mills] That’s right. Next is a pre-applied system used in watertight situations. It’s installed before concrete is poured, and the concrete bonds to it, creating a fully adhered membrane. [Shane Clarke] Nice. [Peter Mills] This is where integrated solutions come in. The Neurofoam XPS Combi Board combines drainage and insulation. It has grooves for drainage, high compressive strength for protection, and provides insulation—around R2.6 for an 80mm board. It’s part of how we deliver cost-effective solutions. [Shane Clarke] Nice. We’ve got some questions coming in already. We’ll drop the data sheet for the combi board into the chat. It has good drainage, but for heavier-duty situations, it can be used with additional drainage systems. Right, next section—how do we select the right system? [Peter Mills] The key is getting in touch early. True value engineering happens in the design stage. We’ll ask questions about geotech reports, soil conditions, water table, contamination, and site details. Based on that, we recommend the most suitable system for both conditions and design. [Shane Clarke] You’ve got a case study there? [Peter Mills] Yes. This was a high-end residential build in sandy coastal conditions. Initially, a very heavy-duty pre-applied system was specified, rated for extreme pressure. But the water table was well below the structure, so it was overkill. We recommended switching to Neuroply 3PT/3PTM—still fully bonded but more cost-effective. The sandy soil also made installation easier with a torch-on system compared to self-adhesive laps. [Shane Clarke] Great example. Now we’ll move into the live demonstration. Alright, imagine a concrete structure here. The slab was poured with 3PTM pre-applied. A fillet is installed at the transition to avoid sharp corners. The team is now installing reinforcement strips at transitions, followed by the main membrane. You can see how the fillet creates a smooth transition. Reinforcement is applied to both internal and external corners. The system is double-layered at critical points and single-layer elsewhere, forming a full waterproof envelope. Next, the combi board is installed for drainage, insulation, and protection. It can be temporarily fixed with adhesive fasteners before backfilling. Finally, the termination bar is installed at the top edge to secure and seal the membrane. Additional drainage can be added if required. That’s a small demonstration of the system in action. Alright, we’ve got a few minutes left. We’ll run a final poll and then move into Q&A. Also, a quick save-the-date—next year we’ll be hosting the New Zealand Building Science Summit in Christchurch, Wellington, and Auckland. Let’s jump into Q&A. [Peter Mills] We do have liquid tanking solutions coming soon, mainly for low-risk applications like planter boxes. For DPC connections, we use pressure-sensitive tapes, but it’s important to note that the connection is only as good as the weakest link—it’s damp proof, not fully waterproof. [Shane Clarke] Some systems are CodeMark certified, others are BRANZ appraised. Board sizes are 600 by 1200. The combi board maintains its R-value below ground due to its closed-cell structure. [Peter Mills] System selection depends on factors like depth, water pressure, and site conditions. In high-risk situations, you’d use a full system with water stops and reinforced joints. Fully bonded systems can also be used alongside additives or internal backup systems. [Shane Clarke] And just to be clear, no tanking system should be installed in wet weather. It’s not worth the risk—you only get one shot at it. Alright, we won’t get through all the questions, but they’ll be answered in the transcript. Thanks for your participation. Today we’ve covered how to achieve that Goldilocks zone—high performance with cost-conscious design. The NZIA survey will pop up shortly. Thanks again, and we’ll see you next year. Thank you everyone.