Designing Warm Roofs for Performance Part 2

[Shane Clarke] So before we start, just to help settle the nerves and warm into it and try and keep it light, tell me the most unusual place you've spent the night. I can start because I dropped the question on you, and intentionally didn't give you time to think about it. Going back about 400 years ago when I was a young fella, we were hunting and we'd shot this fantastic animal and it was just on dark and we couldn't find it, so we ended up spending the night in the bush and woke up the next morning and it was about six metres from where we were. So it wasn't planned but that was pretty unusual. [Peter Mills] I flew down to Wellington for two days and I didn't have any place to stay, so I messaged my mate Ben who was living in Wellington at the time. He goes, "Yeah man, you can stay at my flat, it's a great flat, it's just near Wellington High School." I go there, there's no lock on the door, there's a hole next to the door, the toilet doesn't work, the bath doesn't work, everything in the fridge is mouldy. They set me up on a fold-out bed where the front of it doesn't work, so about this kind of angle. Then I think some people started fighting outside the door at about 3am. So the next day I went, "Okay, look, I'm just going to pay for a hotel." And I text him and I go, "Mate, I'm not staying another night here, thanks for having me." "It's all good, I've moved out today." [Shane Clarke] Have you got one Steven? The most unusual place you spent the night? [Steven Van Rhoon] Yeah, when I was very young, backpacking in Australia, the car broke down on one of the roads and we went to visit the Twelve Apostles towards Adelaide. We spent the night with the four of us in a car and then next morning we went to this local farm because we didn't want to alarm the people in the middle of the night. We got the most beautiful breakfast and reception there, which to this day is my favourite experience in Australia. [Shane Clarke] Fantastic. Very good. All those unplanned things, eh? [Steven Van Rhoon] Yeah, famous Dutch backpacking. [Shane Clarke] Nice. I met my wife there so that's good. [Steven Van Rhoon] Yeah, yeah, yeah. [Shane Clarke] That's why I'm here. Alright, kia ora tēnā tātou katoa. My name's Shane Clarke, General Manager here at Nuralite. Welcome to webinar 40-something. Today is part two of our multi-part series. We're talking about making warm roofs more resilient. With me on the panel, I've got Peter Mills, who's our in-house Gen Z, who's been at Nuralite for about eight years now. Is that right? [Peter Mills] Yep, eight years. [Shane Clarke] And what many people probably don't know is that Pete's normally stuck in the office and he does all our interstitial condensation risk analysis. He does all our tapered plans. And we just thought for a treat today we'd wheel him outside and he can tell us a little bit about this project that we've worked on. He's an internal technical advisor. Is that right? [Peter Mills] Yeah. [Shane Clarke] Or technical advisor? We dropped the internal. [Peter Mills] Did we? [Shane Clarke] Okay. Because we do take him out sometimes. Also on the panel with me today, I've got Mr Steven Van Rhoon, Director from Samson. Welcome. [Steven Van Rhoon] Thank you. [Shane Clarke] You've been there some time now, some 20-odd years? [Steven Van Rhoon] Twenty-three years, yep. [Shane Clarke] Nice. So those who don't know, Samson is our favourite Nuralite applicator today. And for the last 30 years Samson's been an installer of Nuralite products and systems and obviously instrumental in the project we're going to be talking about today. And obviously the instances we're talking about are how we make warm roofs more resilient. Alright. So this webinar is set for 30 minutes. Even though we're here with our friends today at PodLab, this is a webinar. I understand the difference is that the webinar is interactive. You'll see at the bottom of your screen there there's a Q&A function, so feel free to drop some questions in. At the end of the presentation we'll run through the Q&A and give you some of the answers. If we don't get through all the questions, that's fine. Everyone who registers today will get sent out a pack with all the answers typed into a document there. So if we don't get to your question, we'll get back to you. There's also a couple of polls towards the end to keep it all interactive. Today's topic is just an extension of making warm roofs more resilient. Warm roofs are a thing. You would have seen it in your experience. We all started off, however long ago, with single-layer membranes on plywood and that was called a roof. We've now evolved to two layers of membrane, and now we've evolved to this layer of insulation on top. So if you're not sure what a warm roof is, flick back to the first part of the webinar. We ran through that and did a bit of an overview of what a warm roof was. For us, you've probably seen it Pete in your eight years as well, that it's now a big part of our business. [Peter Mills] Yeah, about 50% probably. [Shane Clarke] Yeah, so when I was there 10 years ago, 5% of the roofs were warm roofs. We were pushing them hard and we're just seeing that they're a big part of our business. And you've probably installed more warm roofs now than cold roofs are becoming part of your business. [Steven Van Rhoon] Not quite yet, but we're getting there. The last 10 years it's taken off really well. [Shane Clarke] Big take-up. [Steven Van Rhoon] Yeah, right. [Shane Clarke] And the reason for that, there's a couple of reasons. People are demanding better performing buildings around thermal envelope and things like that. Latest changes to H1 in the Building Code. We do need to increase R-values and the only sensible way to do it is put the insulation on the outside of the structure. So warm roofs have been a big uptake in our business. So it's important to make them more resilient. [Peter Mills] Well because we've been making learnings as we're going along, right? When we were going from one layer to two layer, there's takeaways from what you can and can't do there. For instance, cutting triangles out of one of your layers. But also warm roofs being so different, there's a lot of hidden things that we've picked up on the way and I think a lot of that is coming through to this webinar. [Shane Clarke] Exactly. Bulletproof. So today's webinar is important to you as an architect, designer, builder. I mean, we assume that's who's here. And Mum, hi Mum. So MBIE are planning some significant changes around legislation to designers. We're moving from joint and several liability, changes around professional indemnity insurance. It's going to be even more expensive to become a registered architect. So we think this is why this topic today around increasing the resilience of your warm roof is important to you guys. I guess the whole conversation is going to orbit around this one key message, right? Nuralite can de-risk your warm roof. The last webinar we talked about the types of insulation. We also talked about fixing types and electronic leak detection, so we don't need to cover any of that today. Today we're going to talk about compartmentalisation or night joins of the warm roof. We're also going to talk about outlets in the substrate, which is an evolution. In addition, we're always trying to continually improve what we're doing. And we're also going to touch on how to create bulletproof penetrations. So the project is a Fisher & Paykel building. It's called the Home Office, so it's Fisher & Paykel Appliances Headquarters. [Steven Van Rhoon] It has three sections: the Garage Building, the Shed Building and the Home Building. And we installed about 6,000 square metres of warm roof to the Shed and the Home Building. [Shane Clarke] Okay. So quite a large area. [Steven Van Rhoon] Substantial size. [Shane Clarke] And it's in Auckland, right? [Steven Van Rhoon] It's on Great South Road. [Shane Clarke] So that's the project. Is it finished? [Steven Van Rhoon] No. Actually you get a bit of a sneak peek at the project because it hasn't been officially opened yet. So you can have that for free. [Shane Clarke] One of the unique things to me is this building is made from timber. Completely made from timber, yeah? [Steven Van Rhoon] Timber cross laminated, three storeys and the biggest building of its kind in New Zealand at the moment. Quite a special building. [Shane Clarke] And you worked on the previous largest mass timber construction, the City Mission HomeGround. [Steven Van Rhoon] Auckland City Mission had a similar design, yeah. [Shane Clarke] So all the floor slabs in this instance, when I say mass timber, it's all CLT, cross laminated timber. Quite a unique building. [Steven Van Rhoon] Absolutely. Quite a great job. [Peter Mills] It's so cool to walk through. I can't imagine how good it looks now that it's actually just about finished. [Steven Van Rhoon] Yeah. [Shane Clarke] Cool. All right, so that's the project. If we go to the next slide, this picture might not look like much, but aren't you guys excited looking at this photo? [Steven Van Rhoon] Yeah, I'm revved up, mate. [Shane Clarke] This is not a photo you'd typically see on a website. [Steven Van Rhoon] No, you don't. [Shane Clarke] You're not going to put it on a brochure or anything like that. It's a real action shot. [Steven Van Rhoon] It's an action shot. We know you like seeing the real stuff. [Shane Clarke] Yeah, it's the real deal. It's kind of like a behind-the-scenes vibe. So the first point we're talking about today is compartmentalisation, or night joins, of the warm roof. Steven, do you want to talk us through what we're looking at here and the layers if we step through the build-up? [Steven Van Rhoon] On the right side, you can see the vapour barrier that was, in this case, installed before we came on site by the manufacturers. That gave the main contractor some weather-tightness during construction. We had no shrink-wrap structure or anything like that to protect us from the weather, so this was the next best thing to do. You can see the vapour barrier on the right and then the build-up on the left side of the PIR. The night joins are a necessity because every day we close up a section we've completed. By doing so, you create these night joins, which are a vapour barrier running up and over the upstand of the PIR boards. [Shane Clarke] If you can just see that little step there between the lowest level and the insulation level, all of these challenges are pretty much present because of the lack of shrink-wrap, right? I feel like that's a very large foreground element to this project. [Steven Van Rhoon] Whether it's shrink-wrap or not, you should still seal off and compartmentalise your roof. But yes, you're correct. In every proposal we send out, we emphasise the importance of a weather-tight structure, such as shrink-wrap, because it's quite critical to the success of a warm roof. These night joins are a necessity, but they also turn into a quality assurance measure. [Shane Clarke] Yeah, it does. Well, if you can do something easier and be a little more certain that it's going to be watertight, why wouldn't you do it? So it makes sense to advocate for shrink-wrap wherever possible. [Steven Van Rhoon] Yeah. We're seeing clients already talking about compartmentalisation as part of their QA process, so it is good to get them installed and compartmentalised. [Shane Clarke] So on the slide here we're going to show a two-dimensional detail of the previous photo. If you'd like to help explain it. Pete is clever enough to have drawn this detail, so I'm going to let him talk about it. [Peter Mills] Well, I didn't draw this detail. My friend Franz drew this detail. What we're looking at here is a substrate with some primer shown in orange, the vapour barrier layer that was installed in the factory at Red Stag, then our PIR board and a fixing going through it. Finally, the green line in a Z shape is the night join strip of vapour barrier that's going over the PIR and the original vapour barrier. [Shane Clarke] So what's the next stage in the night join here? [Peter Mills] That's our Nuraply base sheet being brought over most of the PIR and being loose-laid over the vapour barrier strip. It's effectively being used as a tarp in this case. [Steven Van Rhoon] It's basically sealed off for the night. [Peter Mills] Yeah, for the night. And then in the final step, this is the completed roof. The night join has been covered over with more PIR. The base sheet that was previously loose-laid has had the film removed and has been rolled over the entire surface so that it's properly waterproof in its own right. The blue layer at the top is our second layer, the Nuraply 3PM cap sheet. At that point, it's a finished roof. [Shane Clarke] So if we just throw back to that photo, which I think is the next slide, hopefully that helps explain what we're talking about, right? [Peter Mills] Yeah, this is effectively photo two, where the base sheet is being used as a tarp. It's just that in this photo it hasn't been fully rolled over because they're still working on it. [Shane Clarke] Well, it's an action shot, right? If it were a GIF or something like that, you'd see the next step and the next step. [Peter Mills] Yeah. When we show up on site, we don't say, "Hey guys, we're thinking about this for a webinar in twelve months, make sure it's staged." [Shane Clarke] No. This isn't even our photo. This is your photo, Steven. [Steven Van Rhoon] Yeah, correct. One of the QA photos. It shows the layout, where the compartments are, and so on. [Shane Clarke] I just want someone to talk about compartmentalisation. If you do get post-trade damage or something like that, and the roof is compartmentalised, you can electronically leak-test that particular section. [Peter Mills] In this case, the night joins are incidental, but you can deliberately create them. When you arrange the night joins in this way, they become compartmentalisation. If, for instance, you place a night join around an outlet or a pipe penetration and that area ends up failing, moisture ingress is limited to that section. You can leverage that approach to make sure the entire roof doesn't become a problem. [Shane Clarke] So on a large roof like this, around 6,000 square metres, if there was some post-trade damage from skip bins, scaffold poles or other activities, which unfortunately is quite common, compartmentalisation would allow you to localise the damage and identify it using electronic leak detection. [Peter Mills] Yeah, absolutely. If you don't have those compartments in place and water gets underneath the membrane, it can travel freely. [Shane Clarke] That's right. The damage could be enormous. [Peter Mills] It could be anywhere. [Shane Clarke] And that's pretty important on a 6,000-square-metre roof. [Peter Mills] Absolutely. [Shane Clarke] One of the highlights I'd like to touch on is that the timber was supplied by Red Stag in Rotorua. The panels, which were around 180mm thick and several metres long, were prefabricated in Rotorua and the vapour barrier was installed there. They could then be transported to site while remaining weather-protected. I think that's a pretty unique solution for a project like this. [Steven Van Rhoon] When we came to site, we repaired some of the mechanical damage that naturally occurs during transport and handling, but it was an easy fix. Overall, it was a very good system for providing the client with weather-tightness during construction. [Shane Clarke] It's probably a good time to acknowledge the teams involved, including Naylor Love, RTA Studio, and yourselves, who all worked together to solve problems throughout the project. Pete, you've been involved in this building for nearly two years, going right back to the design phase. It's a long journey and it's really valuable to be involved early. [Peter Mills] Early contractor involvement is crucial to the success of a project like this. [Steven Van Rhoon] Absolutely. Especially for a complex roof system like this. [Shane Clarke] In this photo we're looking at what I'd call stage two of the night join. We've lapped the base sheet down over the joint, which gives us a great segue because right at the front of the photo we can see what we'd call an outlet in the substrate. It's actually part of the siphonic drainage system for this project. That leads us into the next topic: outlets in the substrate. This is another evolution of the warm roof design. What are we trying to achieve by putting an outlet in the substrate, Pete? [Peter Mills] In the event that someone damages the membrane and moisture enters the warm roof build-up, we want a way to remove that moisture without having to remove the entire roof system. The best way to do that is by incorporating an outlet. [Shane Clarke] And from your perspective, during construction this building wasn't shrink-wrapped because it was simply too large. [Peter Mills] That's right. You need drainage during construction. With the vapour barrier installed, any trapped water can build up like a swimming pool, so you need drainage in place, whether it's temporary or permanent. [Shane Clarke] And whether the membrane is damaged during construction or years later, having an outlet in the substrate provides an indication of whether water is entering the system. It's otherwise very difficult to detect. [Peter Mills] Almost impossible. Usually you don't know until water appears internally or starts exiting through one of the outlets. [Shane Clarke] I could be wrong, but with concrete construction, you often end up with a warm roof area that's effectively a bathtub, and PVC drains are cast into it. There's an argument that you could cast one of these outlets instead. [Peter Mills] Absolutely. Or simply core-drill and install one afterwards. It works either way. [Shane Clarke] Here's another detail that Peter definitely didn't draw. Can you talk us through it? [Peter Mills] On the left-hand side we have an Aquanite clamping-type outlet. It's essentially a PVC moulded drain with brass lugs that support a clamp ring. The membrane sits between the drain body and the clamp ring, and the ring mechanically secures the membrane in place. In the drawing, the membrane is shown as the blue line. The dome-shaped component at the top is the grate assembly. Together these elements restrain the membrane and provide long-term waterproof performance. [Shane Clarke] And what's happening on the right-hand side? [Peter Mills] It's the same outlet but with a flat top instead of the dome-style leaf guard. The flat design allows other components above the roof build-up to sit over the outlet unobtrusively. In this detail we've capped the outlet because it's clamped into the vapour barrier and needs to remain sealed. That's only one option though. I've seen other systems where the outlet is connected to an indicator pipe. The clear pipe extends into a plant room or maintenance area so you can visually confirm whether moisture is present. [Steven Van Rhoon] Or alternatively connected into external plumbing. [Shane Clarke] That wraps up the substrate outlet concept and shows why it's a valuable evolution in warm roof design, providing another level of redundancy. Let's move on to the next slide and talk about bulletproof penetrations. Not actually bulletproof, of course. Please don't shoot bullets at them. [Peter Mills] That's a pretty poor dad joke. [Shane Clarke] It's all I've got. In a perfect world, Steven, we'd complete a membrane roof, nobody would ever walk on it, nobody would ever install equipment on it, and you'd sleep very well for the next twenty years. [Steven Van Rhoon] Absolutely. [Shane Clarke] Unfortunately, that's not what happens. [Steven Van Rhoon] No, it isn't. But these Nuralite fixing plates are excellent. We've installed just under one thousand of them at the Fisher & Paykel Appliances Headquarters project. We're well versed in how they perform and they're a very good solution. [Shane Clarke] What we're looking at here is a 2D detail of the Nuralite fixing plate. We're going to show a short installation video shortly, but we should probably explain why this detail is important. [Peter Mills] To a lot of people, this just looks like a bit of membrane and a fixing. Historically, roof anchors and restraint systems have often been a source of water ingress. Penetrations are always one of the highest-risk areas on any roof. What's important here is that the fixing doesn't directly compromise the integrity of the warm roof because it's protected by the membrane cap and vapour barrier patches. [Shane Clarke] For those who haven't seen these before, there's the underside plate, the membrane running across the top, and then a stainless-steel puck that mechanically clamps the membrane, very similar to the outlet system we just discussed. It also incorporates a bead of sealant. [Steven Van Rhoon] Exactly. It's a factory-made unit that's simply positioned and installed onto the roof, providing confidence that the penetration will remain watertight. They're designed to protect the membrane and preserve the integrity of the warm roof, especially where other trades may introduce solutions that don't necessarily comply with waterproofing requirements.