Tanking for Underground Situations

[Shane Clarke] Morning all, we're just going to wait about 30 seconds while the room fills up. Bear with us for a moment. Cheers. All right. OK, we'll kick off. Kia ora, tēnā koutou everybody. Thank you very much for joining us here today. This is our 12th webinar, not looking forward to next week's because it's the 13th, so hopefully this goes well. For those of you who don't know me, my name's Shane Clarke, I'm the General Manager here at Nuralite and Nuralite's been synonymous with waterproofing solutions for about 50 odd years now, and we've been doing these webinars for a while now, and we thank everyone for their participation. And you can see in the first picture here, we've got a couple of up and coming webinars. Like I said, not so sure about the 13th one, so there we go. I am looking forward to the one on the 3rd of December, a bit of a behind the scenes at Nuralite. We're just going to take you through a bit of a walkthrough of the Auckland facility, show you who we are and what we do. So this particular webinar is about tanking for below ground situations, which is obviously very useful, we don't tank above ground. And I'm very lucky to have with me on the panel Rod Southwood from Nuralite, he's our Client Manager for New Zealand, even though Rod looks like he's only 21, he's got about 50 years experience, so we're very lucky to have him here with us. Also have Elton Sturmfels, Managing Director of Samson, who has 40 years experience in speciality construction, in particular remediation of below ground tanking. So I thought it'd be quite good to get someone who actually is involved with the aftermath of tanking involved. For those of you who don't know, every participant that comes to our webinars, we donate $10 to our chosen charity, and today's charity is Legacy, who is a non-profit organisation who's all about creating better biodiversity for our marine environment. So a very worthy cause, particularly coming into summer, fishing seasons and whatnot. So thanks again for your participation, you've already made the world a better place. Right, we're going to start off with a poll. First poll, and I encourage you to interact with us here and use your keyboard, otherwise you'll be sick of the sound of my voice after 30 minutes. So please participate. Have you had any issues with tanking after its installation? Quite keen to sort of see who's in the room, what sort of feedback we're getting, and potentially what sort of questions we'll get to at the Q&A session. So feel free to put your answers in there and we'll share those results. So this is set for 30 minutes, it's nice, short and sharp. Throughout the presentation, please feel free to comment, question, etc. And we've got about six minutes at the end to run through those. If we don't get through all the questions, we'll send them out via word document to all the participants. All right. So, yeah, today we're going to talk about below ground waterproofing, why it's important, what are the options. We're going to talk about different types, you know, is it pre-applied, post-applied, probably define some of those and hopefully answer some of your questions. Just a special shout out and thanks to Auckland City Council, who are participating en masse today. We've flipped them a quick morning tea and I believe they're all sitting there watching us. So bring on, bring your questions on. All right. I'm going to throw to Rod Southwood now, who's going to talk to us about some basically the need for below ground waterproofing, why it's important and what happens if you don't. So over to you mate. [Rod Southwood] Yeah, thank you Shane and welcome everybody. Yes, so obviously our webinar today is about tanking and the importance of keeping water and moisture out of your below grade masonry buildings. This particular shot here is a Nuraply 3PTM under slab membrane placed on site concrete. And the whole objective here is, as I've said, is to keep this moisture out of your building. You can only do this once, so the idea is to get it right and obviously ensure that you specify the system that best suits the area that you are working in or designing in. So here we have a selection of different types of tanking. The first one is internal tanking. In other words, this is like a hydro epoxy type material, there's a few variants on the market. In our experience, this particular product is mostly used in the remediation. So for example, buildings and historical buildings that have dampness in the basement, they may not have had complete tanking systems applied to them, or for other reasons. So there are a variety of internal products. Nuralite sells a product called Nuracoat Hydro Epoxy. That's a fantastic material for masonry inside these areas to retain moisture. It's important to note that for these products to work that the substrate must be clean. There can't be coatings or paint on them, plasters, they need to be stripped back to the basics for this product to work. [Shane Clarke] So you'd say that this particular type of tanking internally is far from ideal? [Rod Southwood] Yes, correct. I don't think I've come across a job yet where internal like that would be your proprietary waterproofing system, but certainly beneficial for those that can't excavate or it's impossible to do so and provide some level of comfort, as no one likes that moisture in the basements with smell and mould and etc. One of the downsides of that, of course, would be that your structure is already wet, isn't it? Correct. Then we move on to additives, and there's some great additives out there. Nuralite aren't in that market. These from what I've seen are generally in different type of areas. What it pays to understand with these is do your research. Like I said, we don't actually sell these, but do your research where you're going to use them, look at the potential of hairline cracks, what happens if the crack is a millimetre. So these things all need to be carefully thought about and used in the right location. Then we have the third picture there, which is unbonded. So in other words, that's like loose laid. These are like hydrophilics specifically. So yet again, Nuralite aren't into the unbonded market. These products rely on continuous compression. So yet again, you need to do your research with these, bearing in mind things like liquefaction, massive subsidence, water streams and water flow, anything that can undermine the surrounding material. So much like a hydrophilic water stop that's placed in cold joins and concrete. These are restrained by the concrete structure and they work by swelling. These products are very similar to that in a variety of forms and, hey, suitable for certain situations, but do your research. As I said, you need constant compression for these to work effectively. And then we move into the last slide, which is where Nuralite like to camp. And these are fully bonded systems and these come in a variety of sorts. Nuralite have a couple of options, which we'll talk about more in depth shortly. But for example, the Nuralite 3PTM bitumen system is a mechanical bond to the concrete below the slab and the footings, and it's adhered to the walls. So that gives you that fully bonded. So if you have subsidence, in fact, we were on a job in Titirangi a couple of years ago on a hillside on a massive build, and they had massive subsidence. And when we went to site, the membrane was still adhered to the concrete structure. So although that was quite a dramatic case, these can happen in more minor instances. But you still have your membrane retained to the structure. [Shane Clarke] I guess in that situation, we were lucky that the building was under construction and got the opportunity to see it. I mean, 99% of the time you won't see it. [Rod Southwood] And they had to instal sheet piling to retain this and beef it back up again. And obviously, what we find is that fully bonded systems prevents lateral water movement, which we'll touch on a bit more with further slides. But that's also important. This particular slide here is showing what could happen if you have inadequate tanking. On the left, obviously, you can see moisture ingress, efflorescence. This is not an ideal scenario. The picture on the right is showing a bituminous membrane adhered to a wall. And that's going to prevent that from happening, provided that you choose the correct system as a system for that situation. So obviously, the picture on the left is what we don't want and nobody wants to see. Yeah, nice. [Shane Clarke] Cheers for that, Rod. So you touched on something there. You mentioned a hydrophilic water stop there. Just for actually a quick insight here. My mum was asking me what I do for a job on the way to work this morning. I said, tune in and find out. So be on your best behaviour. Can you explain to everyone out there sort of what a hydrophilic water stop is and what it does, how it works? [Rod Southwood] So basically, a hydrophilic water stop, much like anything hydrophilic, is a product that swells and expands with the introduction of moisture, vapour or water. And the idea being that when they're put in the correct environment, they swell up and they prevent the passage of water. So a hydrophilic strip, which is quite commonly used in cold joins and concrete, in fact, in Nuralite's details for tanking, we note them in certain areas. These are in a strip form. These are a backup. So if there is any major issues with the build in the future, who knows what it might be? It could be a minor earthquake. It could be anything that ruptures tanking. Then these hydrophilic water stops are a great backup. As I said, they swell and prevent that moisture ingress. And in a cold join situation, as you'll appreciate, they do have concrete around them that restrains them so that when they swell, there's pressure that make these work. And that's the same with the hydrophilic type of tanking membranes. They rely on compression. If you put a hydrophilic on one side with nothing on the other, well then it's not going to do its job. It needs to be restrained so it can swell and do that job. So these things exert some great amount of force, don't they? [Shane Clarke] So, for example, they need quite a bit of concrete cover? [Rod Southwood] Yes, they do. Different hydrophilic water stops have different concrete cover requirements. So it pays to check the research on those. The minimum I've seen is 50 mil cover either side. Some of them take up to 75 millimetres. So it certainly pays to look into the literature as to what cover you need. [Shane Clarke] Awesome, mate. Hey, thanks for that. We'll come back to you later on, mate, and ask you about the specific Nuralite types of membranes. Excellent. I'm going to introduce Elton Sturmfels, like I said earlier, he's Managing Director of Sansom. And I understand he's done a little bit of tanking before. He's also been involved in when things don't go to plan. We were talking earlier before we came on the air that, you know, you can draw a two-dimensional line perfectly. I think Elton said even in Revit, you can actually flip the building upside down and repair it. But Elton has some real on-site experience and we're going to let him have a crack at this now. Cheers, Elton. [Elton Sturmfels] Thanks, guys. I'm not quite sure where to start that 20 years of tanking and being my favourite subject in the whole world, it's quite hard to know where to start. But certainly the remedial side is something that you just touched on. You learn a lot about tanking systems and a lot about failures and what we should do on the next job because, you know, 1% failure on a job is a leak. So even 0.5% of a failure is a leak. Nobody works to 100% exactly. We try and sometimes it works, but sometimes it doesn't. It all depends on the application and the membrane that's been selected and the site conditions and so on, which is suitable for that job. So, you know, tanking products come in all sorts of price ranges and formulations and so on. Anything from cementitious coatings, just cement and water on the backside of a wall or bitumen membranes or, you know, right out to the upper end of 2mm PVC, loose laid compartmentalised VHDPE liners, all of these things that are gas membranes as well. You know, these are for very different situations, but basically trying to do the same thing and keep water out of your structure, both for the structural integrity of the structure and for keeping whatever the use of the building might be. Just to pull you up a bit there, Rod, on your comments about de-bonded and bonded. We have loose laid tanking membranes as well that aren't of the hydrophilic type. There are particularly tunnel roofs and so on where you lay it and it's a PVC or an HDPE and of course nothing bonds to those products. There are other types as well as the others. [Shane Clarke] Cool. It must be confusing having so many variations and so many types to choose from. I guess you're lucky enough to have the experience, good, bad and ugly, to help you make the selection. [Elton Sturmfels] Yeah, so, I mean, a specifier is really confined by the client's expectations and their own budget, that they imagine that what this is going to be worth, you know, and selecting that membrane right at the start, getting the right one in the design process is really important. When we're doing it, we're asked to assist with it. We consider three things and it's basically the what and the where and the how. What is the use of the building? I mean, is it a computer data room or is it a car park retaining wall that's open to the rain anyway? And secondly, the where, you know, whereabouts on the building, is it a block wall, you know, is it a lift pit? Is it, you know, all of these things, what's the actual makeup, you know, what's the land profile? Is it into a hill? You know, all that sort of stuff. And thirdly, you've got to look at, you know, the coordination of the architectural and the structural drawings, is how is it actually built? Don't draw a line on something that you're not going to have access to later. You've got to get the right system for the buildability of the building. So it's quite risky for a specifier to get all that right in the early stages of a job. So you really just got to talk to the right people, the applicators or the suppliers or even tanking consultants out there these days, to steer you in the right direction without any guarantee of it being, you know, an end job for them, if you know what I mean. [Shane Clarke] Yeah. [Elton Sturmfels] There are some guides out there from engineering institutes like IStructE and so on where they rate buildings, you know, grade the use of the building on the inside from like a basic utility to a better utility or habitable space. And that's a bit of a guide to say, you know, what's permissible in this space? Is it a car park where a little damp spot on the wall is okay? Or is it like a tunnel that has a precast wall in front of the tanking wall that you never see and you're allowed 10 litres per hour every three weeks or something? It's got to be defined what is permissible. And that's the risk really. One of the sayings that we like to say in the industry is that, you know, don't delete the tanking to get a project under budget. You better to delete the roof because you can put it on later. I know that the guys from Nuralite aren't going to like that because they sell more roofs than anybody, but they'll still be able to do it later. And with tanking, you've really only got one shot. You've got a lot of variables. You've got inclement weather. You've got main contractors all over your membrane. You've got all sorts of conditions that are required to get it absolutely right. And then the fixing, well, that's the hard bit because you can't see through concrete. [Shane Clarke] No, that's right. So, I mean, we obviously, you know, we do our best to put the right product in the right situation. And fortunately, you've got the experience. What happens when things go wrong and how do we fix those types of things? [Elton Sturmfels] Again, it starts with, you know, a range of remedial products and it usually ends up being a mix of all of them. And it's a range of different approaches. But the really important thing is to monitor and catalogue these things like start day one, here's a photograph of what it looks like and what's the weather like outside and what season is it and what's happening, you know? Don't try and rush for a solution on a tanking job like, hey, it's not a defect, it's going to be fixed by one coat of paint. You know, this building's a living entity, water is coming from many different areas. It could still be coming from the sky, straight through the building, down through the wall. You can't jump to conclusions. Most repairs are fixed with a simple injection process or a coating like Rod alluded to earlier with the hydropoxy type solutions. Having said that, sometimes your repair leaks in basements and then it comes back. So, it's a living thing. Right, yeah. [Shane Clarke] Nice. No, it's good. And I guess it's really important that your chosen system has the full, and I mean the word system, has the full, I guess, range of accessories to help you do those remediations. [Elton Sturmfels] Absolutely. There's no good specifying a system from a supplier that is just selling the sheet membrane. If they're just wanting to peddle some product and not assist with, hey, the actual buildability of the job, and they're just interested in selling the membrane, then it's likely to be the wrong solution. Often, being where we are, COVID safe down the bottom end of the world, the lead times on these products which you need yesterday are 12 weeks away. [Shane Clarke] That's right. [Elton Sturmfels] So, you've got to go with a reputable supplier with a full system. Yep. [Shane Clarke] Just a quick question to finish up. You guys don't lay polythene, you don't do DPC, do you? You only do waterproofing, is that correct? [Elton Sturmfels] Correct, yeah. DPC is not waterproofing, it's more for curing of concrete, but it's not warrantable. We provide a flap for people to join onto. I can think of a couple of jobs only where we've assisted the builder in putting the down because we had men, but it's certainly not something that we actively chase that sort of work. It's not a specialist trade. [Shane Clarke] I think it's really good to clarify there that there's a difference between below ground tanking slash waterproofing versus plastic polythene DPCs, they're worlds apart, and not to be confused in the same sentence, I believe. [Rod Southwood] Yeah, and hey, look, I totally agree with Shane there, and one of my biggest bugbears is on the chat that goes to sites for Nuralite, is the use of plastic where they want waterproofing, and there's several issues. One is that the plastic is generally installed by a builder. Two, the plastic is thin and relatively easily damaged by steel and chair installation and the amount of work that goes on. With the damage, although they try and repair it with tape, any hole can create lateral water movement. So, as soon as moisture gets into there, it can go anywhere under the slab. Next is when you get to sites, oh, we want to tape our plastic to the membrane, well, it's not very often that you can actually find it. If you can find it, it's normally crumpled, ripped and covered in dirt, and to think that you're going to take that and have a solution is ridiculous. There's also the taping of it to a membrane, so generally in that scenario you'd have plastic under a slab, people tend to design it under a slab and footing, and then you're trying to, let's just say it was in good condition, it was a miracle, it was clean, it was tidy and it was there, you've then got to tape it to the membrane that's been chosen for the wall. In most cases, the actual membrane itself cut into strips is the best adhesive, and also no one warrants that junction. The applicator that instals the membrane to the walls' warranty and installation stops at the membrane, so there's a weakness there. So, yes, there's a lot of weaknesses in using a plastic tied into a membrane on a wall, and that just has to be carefully thought about. To do that, you would want zero risk, because it really isn't for waterproofing. That's it. [Shane Clarke] No, that's great. I think actually one of the questions that's just come through from the audience was about that, so hopefully that Rod's words there sort of answer that, how we connect the DPC to a waterproofing membrane. Rod's got about 60 seconds now. Sorry about that. He's going to rattle through basically Nuralite's offerings for below ground waterproofing. [Rod Southwood] Sure. OK, so here we have, if you're on our website and you're looking to specify Nuralite tanking systems, these are the boxes that will come up. The first one is damproofing. Now, that will point you in the direction of biturthene 3000 to the walls with your combination of plastic under the slab. And as it notes there, damproofing, it is not saying waterproofing. The middle box is waterproofing. Now, that covers the Nuralite bitumen range, which is where we use 3PTM under the footings and slab, and that has a mechanical bond to the concrete, this is a coarse chip on the membrane. And it will obviously use our 3PT on the walls, which is a code mark compliant, complete encapsulated system. As I said before, when there's subsidence, a lack of pressure, this will stay adhered to the structure, which we find extremely important, which is why it's under waterproofing. When you go to watertight, that is where we bring in the biturthene 3000 and the pre-proof models. And the reason for that is they have around 7 bar or 70 metres of hydrostatic head pressure. This is an extremely durable system. And yet again, total encapsulation, the pre-proof has a combination, actually it has an adhesive and a mechanical bond to the slab and footings, and very tough and durable. So obviously, as I was pointing out earlier with the plastic and the damage, both of these options are extremely robust. They take a lot of hammering, so guys on site laying chairs, laying steel, these things all add up to this full equation. And yet again, being fully bonded, the lateral water movement is eliminated. This particular slide here shows a typical example that would have 3PTM under the slab and footings. It would come up onto the flat of the footing and then have 3PT come down the wall and lap over that 3PTM, so you've encapsulated the system. Internal corners have fillets and reinforcing, external corners also have reinforcing and slightly chamfered edges, so sharp edges and sharp internals we avoid. And we also have a newer drain protection board here, which helps facilitate the water getting down between that and your fill to the drain coil. And also this particular diagram shows a termination bar, which Nuralite have several varieties. This particular bar is holding the newer drain up against the wall, and it's also got a half wine glass to the upper part, which is then filled with sealant. So that keeps that top junction watertight, and it's extremely important that these systems are terminated. Finishing them off with just a membrane is not ideal and not good enough. [Shane Clarke] That's right. [Rod Southwood] So hopefully that... [Shane Clarke] Yeah, that's a bit of a quick overview of the Nuralite offerings. Like Rod said, we're really pleased to announce that we've got our hands on the GCP range of tanking solutions, which we talk about Bituthene 3000 and Preprufe. Those are just the names of the actual products, and one of the questions that's just come in is about the backfill protection. What do we recommend? We've sort of touched on the fact that what we're really looking to do is instal a complete tanking system. So even though we named the names of the membranes, the actual systems consist of obviously the membrane. They also consist of the detail tapes, the detail liquids, the backfill protection board that Rod touched on. Now that's a dimple drainage mat that relieves hydrodynamic pressure and helps that water drop straight to the drainage coil, and also stops hard objects that shouldn't be in the backfill, but sometimes are, puncturing the membrane. So look, we've got about three minutes, we've answered a couple of questions that have come through. There's a couple more we may not get to, but by all means, feel free to bang through a couple more. So yeah, just a bit of a wrap up what we talked about. Obviously below ground waterproofing is very important. You only get one shot at it, as Elton alluded to, otherwise you're going to spend some time down there doing some major remedial works, which is not ideal. Our experience is that the tanking part of, sorry, just to step back a bit, we talked about the DPC connection to waterproofing, it's very limited. It's also very grey, who warranties what, we're talking about damp proofing versus waterproofing, and the actual physical aspects of actually being able to do it on site. So therefore, you know, our recommendation is that you tank, encapsulate, or envelope the whole structure below ground with the same system, and our experience is that this is less than 1% of the total build cost, and it's worth investing in, because like Elton says, you only get one shot at it really, you know. So yeah, a bit of a wrap up now. We're going to come back in two weeks time, we've got another webinar, and then, sorry, which is talking about floated decks on living spaces, and uses for those types of things, and how we can maximise the use of that space, while maintaining waterproofing integrity and warranties, which is all really, really important. I'm going to flick out another poll, which is, could you rate our presentation today? Suggest any further topics you'd like to discuss. We're quite keen to get your feedback, because there's no point talking to a subject that no one wants to know about. So feel free to put your contributions in there. [Elton Sturmfels] Shane, just as a summary, I'd like to say that, you know, get good advice from experienced people. People have actually got a vested interest in the project, whether that's the owner, or the applicator, or the supplier, somebody who cares about the end result of the project, not somebody just trying to sell a product, or trying to tell you that they prefer this one because their auntie's used it once on their basement. It's got to be specific to the job. And then secondly, is if anybody ever says, hey, a little bit of water is permissible, that needs to get defined. You need to say what actually that is. [Shane Clarke] Yeah, right. How much is a little bit? How long is a piece of string? [Elton Sturmfels] Yeah. [Shane Clarke] Great stuff. All right. Where are we going? Oh, we're going good with time. And our third poll is, would you like a follow up? And by this, we mean, you know, do you need, would you like us to contact you ourselves or Elton to talk about a particular detail, or even get a little bit more technical information, you know, with regards to pre-applying membranes to wet concrete, etc. We're more than happy to help out. It's, like I say, we've got half an hour, so it's pretty hard to sort of cover everything. What we're going to do at the end of this is we're going to post out all the questions that have come through. And obviously, there's a wonderful recording, which you can keep forever. And we're also, what are we going to send out? The actual product brochures and that that we talked about with a little bit more defined technical information in them. All right. Hey, thanks very much for your participation today. Thank you very much to my panellists. Thanks Mum. And thanks for everyone else participating and your contributions to Legacy. We look forward to seeing you on the next one. And yeah. Bye for now. [Elton Sturmfels] Thank you very much. Thank you.