Design Principles of the ARA Parka Wrap Retrofit

[Shane Clarke] Tēnā tātou katoa. My name is Shane Clark. I'm the general manager here at Nuralite and it is my privilege to bring you our final webinar of the year. Thanks for all the attendees who have joined us today. I'm looking forward to this one. For those of you who don't know, we run a series of webinars. We do one a month. We cover all sorts of different topics. They're all available on our website on the education page. Feel free to check out those. Today we are talking about exterior insulation. I guess that's a big overall topic that we're covering, but we're actually going to then boil it down and talk about a specific project that we've worked on called the Ara Parka Wrap pilot project. We're going to boil down to the attributes that we've provided for this particular project and cover the external insulation factor. On the panel with me today I'm joined by the letter J. I've got Jon Davies from Parka Wrap Ltd. I've got Joe Lyth from Respond Architects and John Simmons here of Outright, our Managing Director. Welcome to the panel. Thanks very much for your contribution to this project. This is a little bit of a different webinar for me. It's a topic that I'm not completely all over, so it's great to have some experts on the panel talking about this. If any funny questions come through from me, they probably genuinely are from me. I'm looking forward to learning more on this. Before we go on, we're just going to talk about our webinars, how we structure them. There's a Q&A section at the end. Feel free to chuck your questions into the question machine at the bottom and hopefully we've got sort of five or six minutes at the end there to run over some of your questions. We'll then send this recording out with any questions we can't answer. I would like to make this as interactive as possible rather than looking at four heads talking at you, so we're going to run a poll. We quickly just want to ask the room, what type of house you currently live in? Is it a cold and damp home, or would you describe it as warm and dry, or do you have to wear jersey? So we're going to run that poll now. Feel free to exercise those fingers and put your contributions in. [Jon Davies] This is staged Shane, that is fully staged. Your warm and dry house there is Jo Lyth's own home, certified passive house, guaranteed to be warm and dry and comfortable and healthy. [Shane Clarke] We need someone in the webinar to be able to tick the warm and dry box, otherwise the poll would look staged, wouldn't it? Well, that's true. [Joe Lyth] Unfortunately, analysts can't vote, unfortunately, Shane. [Shane Clarke] Oh, your panel can't vote. Excellent, excellent. Oh, wow. Got a lot of warm and dries in here, which is great. Awesome. [John Simmons] Well, thanks for that. It says there, Shane, about 40% are cold and damp, though, which is actually what you'd expect. [Shane Clarke] That's what you'd expect, I guess, if you look at the New Zealand healthy stock as a whole. Yeah. Pretty good snapshot. All right, so we're on to the Ara Parka Wrap Project itself, talking about the challenge. Now, I guess coincidentally, I guess, is that the Climate Change Commission report just came out last week and made some recommendations. And number 14 on the list was about retrofitting our existing housing stock in a healthy, low energy manner, which was one of the recommendations they made. So someone wants to sort of run with the challenge to talk about the existing statehouse. [Jon Davies] Yeah, Dan will start at once. So this home is sitting at the ARA Education Charitable Trust site out in Mangere, out of the airport in Auckland. And we were gifted that home to start this project. So it is an ex state home. It did not have any insulation in the walls, old aluminium windows, and it did have insulation in the ceiling and the floors. So the challenge, Joe. [Joe Lyth] Yeah, so essentially, New Zealand doesn't really dictate much around what a healthy home should be. The World Health Organisation recommends between 18 and 24 degrees all year round. But obviously, we need to be able to afford to do that. So this house probably was never between 18 and 24 degrees in winter because nobody could afford all the heating bills. There's also CO2, keeping that below 1000 parts per million, and keeping humidity down to around 60%. So that's the kind of the metrics we've been working to, what we work to achieve a healthy interior environment. When we're talking about emissions, we've got the operational emissions. So that's the amount of energy we pump into the house to keep it to a healthy temperature. There's also the embodied emissions around embodied carbon and materials. And using existing buildings is one of the best things we can do because we're not creating new emissions, because we're reusing the existing fabric, essentially. Yes, we are adding materials to that. And we're going to be doing the embodied carbon reporting for this project when I get a sec. But yeah, reusing the existing carbon stock is something we absolutely have to do to achieve our climate requirements, basically. [Shane Clarke] I mean, alternatively, I mean, otherwise, this particular structure would just go to waste, wouldn't it? If it wasn't. [Joe Lyth] Yeah, back to landfill. [Shane Clarke] The challenge wasn't accepted. Yeah. [Joe Lyth] Yeah. And there's interesting comments around, you know, New Zealand's very lucky, it's got a very green grid. But as a country, our energy demands are only going to go up. And our grid can't hack or can't cope with the demands that are going to be coming. So we need to start reducing energy use, irrelevant of how green that demand is, basically. [Shane Clarke] And obviously, what's really important is the practicalities around the challenge. So we mentioned here about the inhabitants being able to stay in their home. It's probably quite an important point to make. [Jon Davies] Yeah, so that idea there is that for any home, I mean, mine's the same, the one that I'm sitting in now, it needs to be improved. But the cost of moving out, the disruption and moving out away from, you know, just community, schools, work, all of those sorts of things, that's actually a cost which should be factored in to a renovation. So if we can keep the occupants, they could be tenants, but it could just be an owner-occupied building, or even a school building. So if we can lower the disruption on the internal side, that's a big one. And so for this project, for the research that went into this, it was all about working on the outside of the building as much as possible. So adding materials to the outside of the existing structure without tearing out the inside. [John Simmons] And to add to what Jon is saying, like 40% of the people in this have lived in cold, damp houses. There's 1.6 million houses, so you're talking about 400,000 houses need to be upgraded, which is actually what the government agencies say as well. So you can't be doing it over a six month period. We have to have a methodology that can do it quickly. So yeah, there's a huge problem. Yeah. [Jon Davies] Yeah. We think that well managed and well resourced, we can do this over clad overlay of insulation and new windows. We think we can do that in 10 days. That's yet to be proved. This one took us a little bit longer, but we were all sort of part time and learning as we went for this very first full project. [Shane Clarke] Yeah, no, look, I'm sure you guys took away some great learnings from this and, you know, be able to get a lot more economical with your time, you know, with the things you've picked up along the journey there. So. All right. OK, let's kick off with the why, I guess. Why we felt the need to accept the challenge and why we think it's important to Aotearoa New Zealand. Jon Davies, I know you. [Jon Davies] That's good. So let me just give a tiny bit of history on the park erecting. So so the the Parka Wrap name was just the name of some research that I did and completed in the end of 2021. And that was to sort out the way that retrofitting insulation onto the walls could be done. And specifically with the connection from the window to the wall or window to the insulation in a way that that target of the research was successful. It was challenging, even that because typically we don't recess windows or we don't, you know, we use E2AS1 details for windows, which are not very good thermally. That's being very polite. So that's that was the challenge to set up this thing as a well, you've done the window, you've done the window sill. That was actually the main focus. And now we've got to actually roll this into a whole house and make this applicable, make it useful, make it possible to do this for any building. So that that is the challenge we had, you know, as I said before, we were gifted this home to work on and to use as this project. And of course, you don't turn that down. You get stuck in. And we had a whole heap of suppliers, sponsors, people involved. And we'll name some of those later on in this presentation. So why you think it's important for Aotearoa? We've already covered that, right? We've got an awful lot of homes. So the research was focused on the compliant RTA homes. So the ones like this one that had insulation in the ceiling and the underfloor. So it meets the Residential Tenancies Act. But there are eight hundred and thirty thousand of those homes. They have no insulation in the walls at all. So we've got this incredible. So no, they do have insulation, but only in the ceiling and maybe in the underfloor. So that's eight hundred and thirty thousand homes. And then there's a further seven hundred and twenty thousand with no insulation anywhere. But they're owner occupied. You can choose to do what you like. Why is it important? [John Simmons] I think that you've got to appreciate the health impacts of living in one of these homes. It's beyond putting a jersey on or wearing flannel. We actually have doctors come to New Zealand to study rheumatic fever because we're leading in can't find anywhere else in the world to go and do their research. You know, it's a ridiculous place to be. And we kind of think that we are in a tropical climate, but actually we live in wooden tents that just aren't suitable for us to live in. So it is a really big issue for us. And it affects the health care budget more than the energy budget. [Joe Lyth] Yeah, that's the main reason I got involved, to be honest. I mean, we were living in a 1990s rental and it might have had insulation on the walls, but it was flipping freezing and got into like, you know, eight, nine degrees in winter and up to thirty five in summer. And that's with fans and heating and trying to keep it warm. And my kids were getting sick. So that's why I kind of went down the pathway of high performance buildings, ended up building our own passive house. But as I said, you know, the best building we can build is one that's already built and just improve it. So I just love going on road trips and those fields on the outskirts of Auckland full of those poor little lonely houses waiting to be moved, basically. So I always wanted to get that lottery win, buy one of those and retrofit it. And then, yeah, I got the email from MGMGBC about this project. So. Perfect, basically, yeah, it's been fantastic to work on it. Yeah, so I just I just want to improve the housing stock and make people healthy, basically. [Shane Clarke] Brilliant, that's great to hear the passion coming through. Yeah. All right, we're going to go on to, I guess, a quick description of how it is and what it is. And we've got a nice little image here from Jon Davies, I believe, and he's got a 30 second elevator pitch to basically explain what we did. [Jon Davies] All right. So on the left, existing wall. So this is straight out of the research. This has been superseded in some ways, especially around the window detailing. But the idea is the same. So on the left, existing weatherboard wall doesn't have to be weatherboard. This particular building that we've just worked on is a weatherboard timber frame wall. It had aluminium windows in this window as timber, single glazed in this image, no insulation on the wall. We could try to insulate from the inside. That's disruptive. As we've said, it's actually really costly. But looking from the outside. On the image on the right hand side, that is the new layers, so we're leaving the existing good quality or in good condition weatherboards or cladding in place. There's no reason to move that off the building, really. If that's moderately weathertight, then that's pretty good. And then there's a dotted blue line directly in contact with those weatherboards. So that is a new layer. That's the blue Solitex Adhero from Proclima. That gives us wind tightness and water tightness and an element of airtight, well not an element of, it's completely airtight and it gives us a vapour control. So there's a lot of things going on in that layer. Outside that, in this image, we've shown a fairly skinny piece of rockwool and there's a reason for that. So that's Rockwool from Outright, and I'm sure John would jump in here and tell me a whole lot more about that. It's a continuous sheet of insulation. Now, you can see the black lines running through the middle of the image there, horizontally. Those are long screws. That is one way of installing the battens to the outside of that rockwool. It's not what we've done for this project. So this has been superseded and then there's new cladding on the outside. It's also a new window that's been installed and that new window lines up directly with the insulation and that performance jump is massive. [Shane Clarke] Excellent. Now it's a very clear image there of, you know, obviously putting insulation outside of the structure. It's quite clear that the difference between picture one and picture two. So the next phase was the whole design phase, which is where you come in, Joe. You basically drew this model on a computer and you were able to look at a few of the factors there around the thermal performance. [Joe Lyth] Yeah. So essentially, you don't know, you know, there's a lot of thumbsucking around building design and, you know, you've got your calculation method, sticking some R values, it'll be fine. But actually modelling the building in the actual site it's in with the actual products and the actual conditions will give you a far better idea of how the building's actually going to perform and allow you to then manipulate the specification to ensure you're getting the levels of performance you really need before you even build the thing, basically. So it gives you much more confidence about the outcomes. So I went down on a Sunday and measured up this old house, modelled it in ArchiCAD in 3D and then produced an energy model in the passive house planning package. And what that allows us to do is see what the heating energy demand is in kilowatt hours per metre squared per year, what the overall energy demand will be and what the overheating risk will be, because that's going to be a massive risk as we insulate our buildings. Overheating is going to be quite an important thing to consider. [Shane Clarke] I think the next slide shows some of the, some of your findings and some of your details. [Joe Lyth] Yeah, so essentially, correct. So yeah, so the existing buildings on the right there, you can see it's 168 kilowatt hours per metre squared per year to keep it between 18 and 24 degrees. The proposed building is the green one. So that's down to 27. So that's, I think that was 84% more energy efficient just by adding this insulation on the outside, increasing insulation in the floor and the ceiling, basically. And that's based on five air changes an hour of air tightness, which we're hoping to beat on Saturday. We'll see how it goes. But this just allows us to see, you know, if we wanted to, we can increase the insulation more and try and get out of the passive house. If we didn't want to, didn't need to get to this level, we can, you know, see how far each way we need to go. It also allows us to double check the windows, the type of glass we can use. So it can sometimes save you money because you don't need as much insulation as you think you might, based on the actual results of the actual site, etc. [Shane Clarke] Yeah, right. So I see previously on Jon Davies' slide here, a nice simple two-dimensional cross-section putting insulation outside the structure. That was nice and easy. You ended up with the tricky job of trying to interface it to, you know, because buildings aren't just walls, are they? So you have to interface it to roofs and whatnot. [Joe Lyth] And it's always the junctions which are the challenge, both to keep your insulation continuous and the main challenge is around air tightness. So you can kind of see where we've got green dotted lines at the head and the sill of the wall. That's where we are transitioning the air tightness from the blue wrap to the ceiling at the top there, wrapping around all those top plates and trusses and bottom cords and all sorts of things. And at the bottom there, continuing that underneath the underfloor, removing the existing insulation, spraying on the underside of the strand board and then insulating between those joists again. So getting those details just right. And this is just a 2D section. When you think about a corner of a building in 3D, you've got two walls and a piece of roof meeting and all these different bits and pieces. So yeah, that's, I think Jon was down there a few days ago, spraying goop over everything to try and get it continuous. So we'll see how it goes on Saturday. [Shane Clarke] Excellent, alright. So that was the modelling. Now another, I guess, important factor we've talked about, you know, the design and things like that. We need to control the air. Jon, you mentioned something about that blue layer being controlling your air in the building. [Jon Davies] Yeah, so the air barrier layer, as named here, that's a really critical part to this. So all of the modelling that I did using the same software that Joe was using. So when I did this in the research, I looked at existing buildings and looked at one in particular, actually in Rotorua, and looked at how much air is being just driven through the building because of the draftiness of that building. So that's through the walls. And so what we're looking at with the blue layer is just stopping the drafts at extreme level. We're going for a deliberate air tightness line and connection. So that blue layer is airtight, but it also connects directly to the windows. So across that whole wall, and in that image, just so that it's very clear, this is an exposed corner of, this is not unfinished, we're actually unfinished deliberately to leave the weatherboards, where you can see the cursor there, and then the blue layer goes on top of that, the windows get changed, the Rockwool gets added on the outside, and then battens and cladding. So that air barrier is the blue layer and connected to the windows. So the glass is airtight, the seals to the glass to the frame are airtight, the frame to the blue layer is airtight, or wind tight, and that gives us that protection. So if we do that to a building, we really need to look at how we ventilate the building. And so most buildings are built with windows that you can operate, that you can open and close, but that's part of the problem. You have to open and close them. So instead of expecting that to happen, we've installed a dedicated balanced pressure mechanical heat recovery ventilation system from Stiebel Eltron. So that's the image on the right looking into the roof space. That's just a few days ago when I was up in the roof space, and we're yet to insulate across all of that space. So that ducting, it pulls air out of the wet room, so bathroom, toilet, and kitchen area, and it puts fresh, dry, either heated or cooled air into the living areas and the bedrooms. So regardless of whether the windows are opened or closed, those areas are being ventilated. So that is the plan view on the right-hand side, that same system. So you can see the red dots on those pipework. So that's the extracts coming from kitchen area, that's the toilet where the cursor is, bathroom to the right-hand side of that, and then fresh air going back into the other sections. [Shane Clarke] So how does this, Jon, how does the system differ to a typical ventilation system that's on the market? You said something about closed or balanced or something? [Jon Davies] Yeah, balanced pressure. So what we're doing there is there's actually two air flows of, or two air flows, two fans in that system. So we've got one fan pulling air out of the building and ejecting that outside, so that's your wet air going out, and then we've got one fan pulling fresh air in. Now those air streams don't touch, but in winter they give heat away to each other, so the hot air going out from your bathroom and kitchen areas, that is, the heat is given to the incoming air. What that means is we can have an airtight envelope and we can still have fresh air in the building, and that's really, really important. So I think what you're referring to is a very common system here, as the system that will pull air from the roof space, that doesn't technically meet G4 ventilation requirements for fresh outdoor air, that's the wording in the code, and it pushes that air into the building, and it needs to go somewhere. So that is the challenge with those systems, that air needs to go out through gaps and cracks and power points and light switches, and that's not very good for a building envelope, especially if you have insulation in the walls. [Joe Lyth] Yes, it's worth noting that positive pressure systems aren't actually allowed in a lot of building codes around the world. New Zealand's one of the outliers that still allows it, because it's been shown to cause interstitial condensation, because as the building is pressurised, it pushes the warm, wet air into the walls. If that hits a dew point, that'll condense, then you've got condensation and moisture within your wall build-up basically, which will be mouldy. [Shane Clarke] Fabulous, fabulous. Right, let's go on to the next part of the, I guess, the whole holistic approach here of, you know, making these buildings perform better. We're going to talk about the actual thermal control, we've mentioned the air control, and John Simmons, you're going to touch on the thermal control. How did we go about that in this challenge? [John Simmons] Well, this was obviously the exciting bit, you know, for me anyway. But we've been talking about external insulation for four or five years here in New Zealand. It's actually standard, like the US building code, continuous insulation is actually standard. So it's not actually controversial, it's actually controversial, but it's that we don't do it in New Zealand. So we've seen it going on to more, a lot of the high-end or, you know, serious architects who are building multi-dwelling units are using it. But this is the first chance we have to do it on a retrofit situation. What you can see in that image is the insulation is going to be installed continuously on the outside, but it's importantly in line with the joinery. So that actually means that there's no thermal bridging at that point where the two junction, it's actually butted up really closely together. What is quite interesting is when you go to the property, there's two things that people notice. They don't notice the air barrier, they don't notice anything else. They notice the joinery, because it's really different from normal New Zealand aluminium joinery. It's very solid and stable, and that's because it's controlling the airflow. And I'm not even a joinery salesman, but I'd like to have that joinery on my house. And the other part of it is how quiet it is. And so a subsidiary benefit of this whole process is that Rockwool basically absorbs noise, and it's fully encapsulated, so there's no gaps. And on top of that, the joinery is so airtight that the whole place is like a, well, it's almost too quiet, to be honest, actually. [Jon Davies] Yes. So that wall there that the instal crew are working on, that's facing a really busy road. I mean, really busy trucks every 30 seconds. And you stand inside the building now, now that the windows are installed, now that the door is being able to close it, now that the glazing is actually in, and it just is quiet. And a whole part of that is to do with that rockwool facing that road there. It's really good. It's quite interesting watching cars go past, quite hard to hear them. [John Simmons] And of course, I think as Beacon did a report that about a third of a building wall is timber, because we love nogs in New Zealand for some reason. And of course, you have these strange junctions, which I don't know how anyone's supposed to insulate them. But you look at this building, you can actually see the whole thing is wrapped like we put a jersey over the entire thing. And the nice thing about it from an inspection point of view, you can actually sit back and go, there are no gaps. It's all tightly butted. So before we go to the next stage, we've actually checked that we've got a continuous unbroken blanket. [Shane Clarke] Easy to see. Yeah. Very easy to inspect. [John Simmons] Yep. That's in a nutshell, in my 30 second pitches, what we've done. [Shane Clarke] Yeah, yeah, yeah. [Joe Lyth] Just to touch on that as well, John, it's worth talking about the fact this is a process. It's not kind of just some products. It's a sum of the entire process. So the building needs surveying before we start anything to check whether there's any, you know, weather tightness issues or damage that needs remedying before we even start the process. And then there's, because you can see, is it all blue? Great. Looks good. Is it all insulated? Great. Looks good. So the whole process is a holistic approach to look at the building altogether rather than just trying to, you know, willy nilly to change a couple of windows or add a bit of insulation here. It's considering the whole thing as one element, basically. [John Simmons] And what I've read from overseas is taking an ad hoc approach, like a whack-a-mole approach, you actually get the problem elsewhere. And so you think you've done a good retrofit and all of a sudden there's mould growing on a wall that was never there before. So just backing up what Joe said, the holistic approach is what we need to take, not the idea of just going, oh, let's put some more insulation on a roof or let's put... [Shane Clarke] No, it's great to see such a, I mean, when we get on to, you know, thinking the people that are involved, there's just a huge number of people that were involved to actually provide that whole holistic approach. We weren't just putting a window vacuum in the bathroom and here you go, we can now suck up the moisture, you know. Obviously, we went a lot further than that. So I guess, yeah, just to summarise our little soiree today, the overall concept we're talking about is external insulation and then this particular pilot on how you went about it, including the design, controlling the airflow, controlling the thermal, all those important things. Using an existing state house I thought was quite important. You know, there's a lot of these around. New Zealand has a huge challenge to retrofit sort of 400,000 odd homes, but this pilot can prove that it can be done. And I think the secret is that it can be done at scale. I think you get a lot more sort of economies there if you were able to do 30 of these in a row rather than waiting for one trade to finish so the next trade can carry on, you know. And it meets that challenge of the inhabitants being able to sort of stay inside the building. And I'm not sure about the 10 day thing, but, you know, as you learn and go on, you know, we're going to get that economies of scale. And, you know, like I say, if you had a whole street full of them, you'd probably get a lot more time efficient. So is there any other things in the wrap up you'd like to touch on, Gents, before we move on to the questions? [Jon Davies] Possibly that one, well, that next slide is quite useful because what we didn't talk about was the Parker products in there. So it's the one element that hasn't been touched. So what we created, we've created three products that help us with this. So because we've got the ability to use different thicknesses of insulation, we need some products that cope with that thickness change. And we need products that will cope with the depth change from where the structure starts. So in this building, in fact, this wall and this window right there is great because we changed out a stud because it was rotten. We changed the sill underneath that window because it was also rotten. At that point, we've removed a weatherboard in that area. So the starting point for the clips that you can see hanging out of the wall there, those banana clips, that starting point changes. And so there's a hinge. I don't know whether that was visible in those details earlier on, but there's a hinge within that system. So it will come out through the insulation as far as it needs to. And then the batten is connected to that. There's also a window cam underneath the windows, which is quite easy to set up to seat that window on, bearing in mind the window is not sitting inside the frame, it's sitting outside the frame line. And the final one there is a cavity closer at the base of the wall, which allows, again, the thickness of insulation to be modified. So that's the Parka Wrap side of it. Parka Wrap, the process, is everything that we've talked about. And then we've developed some products which assist with that, the system. [Shane Clarke] That's great. That answered one of the questions that's come on already on how we attach the cladding and things like that. So you've mentioned the brackets and that to the very end. I guess, in summary, do you felt that you ticked all the boxes that you met most of the aspects of the challenge you'd set yourself? Do you feel you ticked the boxes there? [Jon Davies] Challenge, yeah. Well, challenge was reduce disruption, improve thermal performance, make it possible to see the QA that you mentioned before, the quality assurance on site. And Joe said, is it all blue? Yes or no. Are the windows connected to that blue layer? Yes or no. Is the rock wall covering up all of that blue layer? Yes or no. So the QA process on site is, I mean, yes, there's lots of other little complex bits, but overall, that approach has really, really simplified the insulation installation part. [Joe Lyth] How are you saying those two words together? It's also worth noting that, I mean, this is the first one. This is, you know, the research, it will be complete, it will be habitable, and we're going to be aiming to monitor it to confirm what the model says, essentially, that it will be lower energy and healthier. So once it's done, it'll be done, and then it's on to the next one, basically. [Shane Clarke] Yeah, excellent. I guess for me, what I've seen, what I particularly like about the whole process is that we've gone from a design, you know, drawn on a piece of paper, then drawn it in CAD and modelled some things, and now we've actually physically achieved something that you can monitor and prove the concept. So what do they call it? Walking the talk. Great to see, great to see. I've got a couple of questions here from some of the participants here online. Why Rockwool insulation and not PIR? [Jon Davies] That's a funny question that I'll answer just to begin with, and then John can jump in, who actually supplied the insulation. We did have PIR, but you can see it in this image here, so there is a strip of PIR in the head of that wall where it connects through to the insulation and the roof space. But my answer to the question is, when I did the research, I built up a physical wall, which was about half the size of that wall in the image there, and had this in our test booth at Oculus or Shelby Wright Test Labs, and I physically tested all of this, physically tested the performance of the elements, and I used Rockwool, and I managed to, when I took all the cladding off, I managed to fill it full of water, and I looked at what it did when it was full of water, and it is pretty amazing how quickly it all dried.