Roof Renewals - Extending the Life of Your Roof

[Shane Clarke] My name is Shane Clarke. I'm the general manager here at Nuralite Waterproofing Limited. And for those of you who don't know, Nuralite's been synonymous with flat roof waterproofing and construction waterproofing, et cetera, for the last 50 years. I'm joined on the panel today by Matthew Cutler-Welsh from New Zealand Green Build Council. And today we want to talk to you about roof renewals, overlays or remedials or rejuvenation or whatever you want to call them. But I'm going to talk about some existing building stock and what we can do to improve them. Just a little bit about our webinars. So they're structured for about 30 minutes. And there's a couple of points we want to make. We want to touch on why we think roof renewals are a good option and what solutions are available and then run you through a very brief case study. So we'll make this as interactive as possible. We'll have a Q&A session at the end. So by all means, feel free to check your questions in as and when they pop up. And if we get a chance at the end, we'll go through a few. If we miss them all, we'll send out a recording of the webinar and you'll also get a full list of the Q&A that goes with that. This webinar is also NZIA accredited for five CPD points. So there's a survey at the end where you can populate your name and your NZIA number and we can attribute those points to you. For every one of our webinars we do, we donate $10 per participant to a charity of our choice. Matthew's chosen a charity for us yesterday during practise, Mates in Construction. I'm not sure if you're familiar with them, but basically Mates in Construction is a suicide prevention programme specifically targeted at the construction market. Our construction industry is losing nearly one person per week to suicide. Ninety nine percent of those are men. So thank you, Matthew, for putting forward that charity. And thank you all for attending. You've already made the world a better place just by being here today. So good on you. All right. So before we kick off, like I said, we'll try and make this interactive as possible. We're going to start off with a poll. So before today, were you aware that it was possible to renew or overlay an existing roof without the need to remove, replace it and chuck it all the way and start again? So just let that sit there for a moment. All right. Thank you for that. All right, if we just click into our first slide and we'll get into it. So this is just a brief overview of why we think, I guess, what the positives are of renewing an existing building. Obviously, first and foremost, is we're going to improve the weather tightness. Ninety nine percent of the roofs that we get involved with renewing start off from that particular point of view around weather tightness. First and foremost, it's one of the things that tenants and building owners notice the most vividly is water coming down the walls, etc. So probably a really good reason to look at fixing up an existing roof. Another example, sorry, another reason would be to minimise any building disruption. So it is possible to actually overlay or renew a roof without disturbing the tenants below, allowing productivity to continue. It also relieves the need to actually wrap or temporary cover the building if we can actually overlay the existing roof that's already there. And a big one for us and a big one for Matthew, of course, is less environmental impact. We're not having to rip off and remove building materials, throw them to landfill and then introduce another whole lot of building materials. So we basically leave what's there and in some cases we can actually use what's there to form the vapour barrier, for example, if we're doing a more roof overlay. So Matthew will touch on that environmental impact a lot later on. And there's also the opportunity to improve the thermal insulation. Very, very difficult to retrofit insulation into an existing building within the structure. Again, you'd be disrupting the tenants, it would be noisy, it would be dusty, etc. There's a really good opportunity when we're renewing a roof to lay a continuous layer of insulation across the whole surface of that roof area. During that process, it's also possible to increase the acoustic performance of that building. And I'll touch on that as we get to our case study towards the end. And as I sort of mentioned earlier about the environmental impact, we're reducing the building waste. There's a couple of reasons why we think it's a good idea to renew an existing building. So we've got a couple of options when it comes to roof renewals. Could start off as a basic coating. Now, these are relatively economical, quick to apply and basically described as a sunblock, if you like, for your roof. They may prolong the life of the roof by another two to three years, perhaps, which may be needed. But of course, it's the old saying, you get what you pay for. So another option could include a membrane overlay. So the existing substrate could be sound enough to overlay with a brand new membrane, either a single layer or a double layer, depending on the situation that we're going over. If the membrane is quite well used. We've also got an option for a recovery board before we put on a membrane overlay. And then, of course, the creme de la creme, if you say, would be the insulated overlay. So we're actually using an insulated PIR board to overlay an existing roof. The situation here, actually, it's not just a flat roof that we're overlaying. That's the good old fashioned standing seam, brown built metal roof that we can overlay. So there's a couple of options. We didn't sort of go into all of those because there's probably about two hours worth of chatting there and we've all got better things to do. But just to give you an idea and sort of an overview of the options that we can offer. Right, I think it's the next slide there. This is where I throw to Matthew and Matthew, is your opportunity to tell us a little bit about you and who you are and what you guys do. [Matthew Cutler-Welsh] Thanks for coming. Thank you. Thank you for having me. Most or some of you might be familiar with the New Zealand Green Building Council already. We are a not for profit organisation with over 700 members now, been around for over a decade in New Zealand and we're affiliated with the World Green Building Council. So we primarily do rating tools, independent third party certification of environmental rating tools across all of the building sector. I look after mostly the residential side of things, but my colleague Brad looks after commercial buildings. We rate design of buildings, how they're constructed and then we've also got some tools that rate the ongoing performance of buildings in collaboration with people like Ika as well. But as that's our core business, we also do a lot of advocacy work. So we're continually trying to increase parts of the building codes to bring us in line with where we think the rest of the world is. We often say that we're between 20 and 30 years behind some parts of the world in terms of the health, comfort, performance of our buildings. So we do a lot of advocacy work there. We collaborate with all of our industry partners and we also educate and that's something that I enjoy as part of my role is getting out and talking to people and bringing some of the building science into the industry to lift the performance. But also something that I really enjoy is seeing people being proud of the work that they do, whether it's designing or constructing or adding to a building. It's a great feeling that people can walk away from a project knowing that they've created a really awesome space for someone to live, work and play in. So let's talk a little bit more specifically about roofs and something that's top of mind for a lot of people at the moment is H1 because a lot of you might have been on Branz webinar yesterday. That was one of many, many conversations going on around the country over the last, well, probably year at least and ramping up towards the end of this year for the full implementation of the clause H1, which is all to do with energy efficiency. Now a lot of people are very fixated on this number 6.6, which is the schedule method of requirements. So that's the minimum requirements if you use the schedule method. Now that probably is overkill for a lot of the country in the residential space. If you're trying to get R6.6 in the roof, it's probably because you either live on the top of a hill in Queenstown or you haven't tried to do a relatively simple calculation or use the modelling method because in a lot of cases, you don't necessarily need to go all the way to R6.6. And there are lots of options for doing that. But that is top of mind is that H1 compliance. But there's a lot more to the building code than just H1. So if we look at the whole building code, if we jump to the next slide there, then there are gaps in the building code. And we know this because our homes, particularly my area of focus, we still have at least half of our buildings that are just uninsulated or very inadequately insulated. So 53%, if you look at the insulation box down there, 53%, this was a few years ago, but unfortunately hasn't changed a great deal. And that lack of insulation is definitely contributing to the mould that we have. And regarding heating, what we find is that if a house is uninsulated, then people are just very reluctant to heat it adequately. So these three factors, insulation, ventilation and heating, all need to work together to have a home that is going to be warm, dry and healthy in the winter, and also keep cool and comfortable in the summertime as well. So insulation is really, really important. All right, jump through to the next slide. Now, we've looked at the building code. This is all the clauses of the building code laid out there. And when we think about true good performance, there are lots of black holes in things that just aren't covered in the code. So the code does quite a good job of making sure the building stays up. There's a really good section there on fire protection, and things like external insulation are really important in that regard. People are very conscious of external moisture. So we're getting pretty good at that now because lots of people got sued about moisture being allowed into the buildings. But we're not so good at dealing with moisture that's generated from inside of the buildings. And that's a multi-pronged approach that's needed there, which relies on ventilation, insulation and heating. We just don't do that very well. And there are a bunch of other areas that just aren't even mentioned in the building code. So these black holes, the labels there are all credits within Homestar version five. And one of the points of things like Homestar Greenstar existing is to bring buildings up to an adequate level of performance. In an ideal world, you could argue that we wouldn't need Homestar Greenstar because the code would look after all these areas. But the reality for us is that there are just these black holes. So if we go there, then dive down into a bit more detail, specifically around roofs. When I first looked at this slide, I thought, oh, gee, there's probably one or two things that are relevant for re-roofs. But when I started thinking about each of these clauses, you suddenly realised just how important roofs are. I mean, you could probably do this for every element, but roofs in particular, they do so much and probably often not. You know, they're one of those things that I think people miss when they're not there or people become aware of them when something goes wrong. You know, they definitely forget about them. [Shane Clarke] Call them the fifth wall sometimes. [Matthew Cutler-Welsh] A well-functioning roof has so many important functions. So I mentioned external moisture, that's a really obvious one. Internal moisture is really, really important and insulation can play a huge role in minimising the impacts of internal moisture forming condensation and then mould and the rest of it. But there's some other elements, apologies for the small text, but some other things in there around internal air quality, sound, so airborne and impact sound. Acoustic control is really important. Energy efficiency is probably one of the obvious ones and just improving the overall thermal envelope. But also embodied carbon. So in version five of Homestar, now also Greenstar, we're talking a lot more about carbon, both operational carbon, but also embodied carbon. So embodied carbon is all the energy and environmental impact of the manufacture, shipping and installation of products and materials. And one of the best reasons for re-roofing a building is that you're saving so much of the existing structure and all that material in that building. And if you can give that building literally a new lease of life, then that's saving a lot of material from landfill, which is another credit there. Construction waste, totally not addressed by the building code at all, but also heavily reducing the amount of embodied carbon for a new period of time for an existing structure. So there's a lot that you can do well by thinking about how to improve the performance of an existing structure by giving it a new roof. A couple of other things just to finish off before I hand back over, we jump to the next slide again. Just very quickly, Homestar version five mentioned a few times, there are three key areas that I emphasise that's a step up from previous versions. Air, that's to do with ventilation. So you need a fresh supply of air from a controlled, ideally mechanical ventilation. Cutting down on thermal bridges. This is a great example of where something like an external insulated part of the envelope, particularly the roof can be really beneficial because by wrapping it all up in a continuous layer, you're getting rid of any thermal bridges and they become more and more pronounced when you start increasing insulation. So external insulation is the best way of reducing thermal bridging, which is really important for reducing condensation. And from condensation, we get mould, then we get health problems. So really good option there. And then carbon, which I've mentioned already as well. And I just want to mention very quickly that while a lot of people right now are focused on H1 and getting up to speed with all the requirements of that, we really want to highlight what's coming down the line. This has already been sent out in draft form a couple of years ago. Some people may have read through the Building for Climate Change framework. We're expecting to get the sort of more formal round of consultation out from MBIE this year. But this is a whole new structure of the building code. And we're really excited about this because it hits on some really key performance metrics, primarily that energy use, which is easily converted to operational carbon. Also, there's water in there, reducing fossil fuel emissions. And we've aligned Homestar V5 with where we think those targets are going to be placed. So look out for that. We're looking forward to getting some consultation so that we can help industry get that across the line. [Shane Clarke] Oh, excellent. Thanks for that. Pointing out what's coming down the pipeline and yeah, we can be ready for it.More and more prepared than we were for H1. All right. I've got a couple of minutes here. I'm going to tell you a happy story. This is a case study of what we've mentioned today about repurposing or renewing a building. This particular focus is on a roof, obviously. So this is the old Bic Pen factory down in Normanby Road in Mount Eden. You can still see some of that Bic trademark yellow there. And the client, Life Church, were looking for a new premise. And this suited them because it was a great location and it's a good sized building. However, most of the roof is tin and it was a factory, so it didn't have people living or breathing inside it as a purpose when they first built it. So I'm just going to go through a quick little case study of what we did here. So this is the existing roof. So it's standing seam, good old fashioned brown, I think they called it, with obviously a metal skin in there, plant penetration popping up through the roof. So our solution in this case was to overlap with a insulated membrane roof. So we packed out the trays of the existing metal roof. Actually before that we had someone come and inspect the roof, the structure, and say that was all good and wasn't going to be, you know, we weren't going to do anything sort of untoward by putting additional weight on it, etc. So the roof was signed off as structurally sound. We then filled up the trays with packers. We then laid a continuous vapour control layer underneath the insulation. We then laid 80 mils of PIR insulation across the whole surface of the roof, eliminating all the thermal bridging. That continuous layer gave them an R value of about 4.5 in addition to what was already below in the ceiling there. And on top of that we laid the Nuraply 3PM membrane system. One of the other considerations around this particular building was acoustics. Due to the fact that we had people inside listening intently, we couldn't afford to have rain noise sort of yelling out what's going on inside. So there's sort of a finished shot of what the membrane roof looked like. 3PM membrane is quite a dense product, therefore sort of having a lot of acoustic attenuation from outside rain noise. So it's just almost a finished shot there. And here we have the last finished shot here. So yeah, it's about 5,000 square metre warm roof overlay as we call it, able to repurpose the building. Of course, there was a lot of work that went on inside the building as well to make it functional. We're just touching on the outside. So yeah, they've got a continuous airtight, watertight, insulated roof with a continual vapour blocker that gives them the thermal performance and the acoustic performance they were after. It's a quick case study there of a good story. And I'll leave that there. We've got a couple of minutes left. We've got a couple of questions coming in in the Q&A. I've got one here. This one's for you, I think, Matthew. You mentioned the schedule method for H1. There are a couple of other methods, I believe, to measure. [Matthew Cutler-Welsh] Yeah, so schedule method is simply just look up a table depending on which climate zone you're in. And there are six climate zones now instead of three that we had previously, which is kind of nice because Nelson has a different climate zone than Queenstown now, which it didn't have before. But yeah, we recommend using either the calculation method or stepping up to the modelling method, which sound a little bit daunting, especially if you're only used to using the schedule method, but they're really not that hard. The Green Building Council, we've got a free calculator. Branz has its own free calculator. So doing the calculation method is not that hard. And often you'll find that you don't need to be having a full R6.6 in the roof. So the schedule method is the simplest form. And there's a lot of overkill there because it assumes that by packing the ceiling out with a lot, you're going to be deficient somewhere else, which kind of works in theory, but not really because that's not how physics works. [Shane Clarke] No, no, you've got to be aware of those unintended consequences, don't we? Packing that ceiling space full of insulation. [Matthew Cutler-Welsh] You do. And there's also diminishing returns to putting more and more insulation in there. If you've got holes in the sides, a bit like putting another lid on top of a leaky bucket. You're not going to get any more benefit for just adding more and more in the ceiling. [Shane Clarke] Yep. Another question here. Oh no, sorry, it's a statement. Just in the chat section there, we've actually popped up our product EPDs. They're available for anyone there who can download those if they like. Another quick question here from Simon. He wants to know what the additional weight was on the church roof. That was around four to five kilos per square metre of additional weight. Probably something to bear in mind when overlaying existing structures. So the PIR board is quite light. It's about 32 kilos per cubic metre. So yeah, split it down to an 80mm board plus the membrane were about four to five kilos per square metre of additional weight. Oh, there's one here, Matthew, about how do you guys account for carbon? You've got a way to account for it? [Matthew Cutler-Welsh] Yeah, so carbon is becoming more and more talked about. Operational carbon is relatively easy because in New Zealand we have a mostly electric grid so we can figure out what the running costs are likely to be and energy demand and convert that to CO2 equivalents per annum. Embodied carbon has been a bit trickier, but companies such as Nuralite are getting EPDs done, which is fantastic. I don't know if you want to talk about the process that you went through to get those EPDs, but for us and our assessors they're really, really useful because it's a high standard of verification of data. Then we can put that into a calculator using an agreed methodology to assess the CO2 equivalents of that, what we call the cradle to gate, the sections of everything from raw materials through processing, manufacturing, fabrication and then installation of the product. All of the energy that gets input into that process, we come up with a number. In fact, it's a whole bunch of numbers, but it's a verified methodology of accounting and converting all of those because it's not just carbon, but we convert that to CO2 equivalents because that gives us an easy way of comparing everything. That's just one line of data in an EPD. I recommend people having a look at those EPDs and just having a look at just how much information is in there. What was that process like for you guys getting your EPDs done? [Shane Clarke] Long, but it was actually by demand from the market, to be honest, as to why it came about. I know it was long and arduous. Of course, we're using materials that are manufactured offshore, so lots of round and round communication with people around the world. We managed to stitch it together. If we can do it, anyone can do it. [Matthew Cutler-Welsh] The first time I heard the term EPD, which is its environmental product declaration, was actually from one of the cement companies. This was more than five years ago, probably close to 10 years ago. It surprised me a little bit. At first, I was a little bit suspicious because I thought, why is a cement company doing this? Is it greenwashing? I've observed more and more companies getting EPDs primarily because of consumer demand, but also because they generally want to do the right thing. What's really useful for us and for designers, specifiers, is that it gives everyone a level playing field to compare like for like and to make those science-based or evidence-based decisions on which products and materials to use and where and how much of them. It's allowing us to make educated design decisions and reducing greenwash because I don't believe that any products are necessarily bad, per se. It's how those products are used and in which situation. EPDs just help us to make those decisions better. [Shane Clarke] A couple more minutes, a couple more questions here. What are the blue dots on the new roof build-up? Good question. We couldn't go into detail, of course, of how every little thing goes, but those blue dots are actually our thermally broken fixing flanges. So, we mechanically fix the PIR board down to the existing structure with a short screw using a long blue hollow thermally broken tube. Approximate square metre rate for a standing seam system depends on the thickness of the PIR board, depends on the chosen R value. And the second part of the question, which we didn't go into as well because we're only at half an hour. Yes, you can overlay it with a second metal skin. This is our tricore system that we work with, with diamond. So, that is also an option. Time for one more. Are you on the living building challenge, the clear list? Yep, our products and systems have a clear red list free certification. We recently did a project down in Napier that needed that. Not many of those in New Zealand, the clear projects, unfortunately, but we're involved with that one down there. [Matthew Cutler-Welsh] That's very impressive to get that certification. [Shane Clarke] Yeah, it's just again, I guess it's a benefit of working with some of the larger manufacturers globally who also find it important for them as well. So, we're able to tap into that. So, we're happy with that. All right, let's wrap up. Thank you very much for your questions. The ones we didn't get to, they'll come out in the written Q&A at the end there. So, hopefully the last half an hour we've sort of given you an idea of why we think roof overlays or roof renewals are a good idea. We're going to give you a quick overview of what solutions are available and run you through a bit of a good news case study. Just before we go, we've got a quick second poll there if you just want to rate the presentation to see whether these things are worthwhile doing. We're getting a really good turnout. So, we do appreciate your feedback into these. And then just the last poll there is if you're working on something at the moment and you'd like one of us to follow up for something that's quite pertinent to what you're doing at the moment, we'll follow up with you after this. [Shane Clarke] All right. Thank you very much, folks.