Principles of Passive House Design

[Shane Clarke] Morena, tēnā koutou katoa. Welcome everybody. Welcome to our 14th webinar and I'd just like to start firstly with a big thank you. Thank you to all of you attendees who have attended our webinars and as we said earlier for every participant that attends our webinars we donate $10 to a chosen charity and as of today we've raised just under $15,000 since the start of lockdown for various charities and today's charity is the Wakatipu Reforestation Fund which is very close to Sian Taylor, our panellist's heart. She was lucky enough to nominate the charity today so that's great. For those of you who don't know me, my name is Shane Clark. I'm the General Manager here at Nuralite and I'm going to, well I'm not going to speak to you about it, but luckily my panellists are going to talk to you today about the fundamental principles of passive house design and luckily enough I'm joined by Sian Taylor from Team Green Architects who is obviously some experience in this field, that's why she's here. Lucky enough to be joining us from a very wonderful looking cafe down in Kewtown somewhere, lucky you, and also have magical Mike Skelton, the National Sales Manager from Nuralite who's also based down in the mainland. So this conversation may be one-sided but we'll see how that goes. So that's what we're talking about today. As you should all be aware hopefully with the Zoom webinars that we have a Q&A function. I do encourage you to be interactive and participate as much as possible otherwise you'll just hear me talking all day and that won't be fun. Towards the end we'll hopefully have a Q&A session to answer any of your questions so feel free to populate that space down the bottom there in the chat function and we'll go from there. We'll pass over to Sian who's going to give us a bit of an overview of Team Green Architects to start with, who they are and what they do. [Sian Taylor] Thanks Shane. So Team Green Architects is a practise owned by my partner Mark and myself and we started the practise I think probably about eight or nine years ago. It was as a result of me completing the Passive House course in Auckland with Cara and as a result of that I felt there was no other real answer to creating buildings which could be warm and comfortable and low energy and basically respond to the climate than Passive House design. So that was the main reason for starting the practise and it was a fundamental principle to what we do so it's something that we incorporate in every single one of our designs and it doesn't always mean that the Passive House standard is reached but essentially the whole philosophy behind Passive House and the energy modelling which is done through the Passive House planning package which is the software is used for every single building and what that essentially means is that you get to see how the building is going to perform relative to its climate and that's probably the biggest thing that I like about it. It does create constraints around what you do but the constraints are telling you how well that building is going to be behaving and how much energy it's going to be consuming. So one of the big things you're aiming for and one of the big things it can give you is comfort. So the biggest thing I guess I noticed when I first came to this area which is now sort of 16 years ago was how poorly the buildings were behaving and how we were still reliant so much on plugging in heaters, hot water bottles, electric blankets, things which me being from the UK we just didn't have and the buildings were still cold so you go to the toilet at night and you're absolutely freezing and it just didn't make any sense and not only were the buildings far too cold especially in our climate down here in the South Island but in the summer we were overheating, there's too much moisture in the buildings, we've got massive issues in New Zealand with health problems because of the buildings that are produced and it just all seemed to be done on the fly there was no science behind the insulation or the construction of the buildings it was just if there was a cavity that was left by the framing that was required due to NZ 3604 then that was what you got in terms of insulation there was nothing else to it. So one of the first things I remember trying to do at one of the practises I was working at was trying to ensure that the slab was thermally broken because we're heating this slab and there's no requirement to insulate it so you're heating the outside and it just seems so crazy that that's what we were doing so it was a big thing at the time that was you know like I said 15 years ago now and trying to persuade the engineer that he had to put a break to insulate the slab and obviously now we've got a lot better ways of doing that but at the time it was a big thing. So passive house what I just to explain what it is for those of you that don't know and there's some fundamental principles which are quite logical so we've got the idea that we've got to highly insulate the building and I think of it like a thermal blanket that you're wrapping up the building and that does two things it means that you are protecting the building from being too hot in the summer but also obviously in the winter keeping the building warm and the insulation is a combination of insulation in the walls and avoiding thermal bridging but also high levels of glazing which again it's suitable to climate so here in Queenstown we have to use triple glazing and the frames are obviously quite important or very important I should say as well as the glass so avoiding heat loss through windows is huge it's the biggest source of heat loss in our buildings. In Auckland or pretty much anywhere but Queenstown or the central region that we're in it's much easier to achieve the passive house standard because the climate is a lot more mild we've got the extremes here in Queenstown we've got extreme cold and we've got extreme hot so it's this massive range that we've got to deal with but the passive house planning software which is the energy modelling gives you the ability to plug in the climate data relative to where you are and then you alter that to suit where your building specifically is and then that tells you how your building is going to operate and you orientate the building and you're putting things like natural shading of mountains and trees and so on you just see how your building behaves so the other big thing with passive house is that you're creating an airtight building and that's something which I think is still quite misunderstood in New Zealand the idea of airtightness I think freaks people out and to explain it's not it's not completely airtight you've got its breathable membrane so I try to explain it to people a bit like a Gore-Tex jacket and you wouldn't go up on the mountain in just a woolly jumper you'd be putting on a breathable windproof membrane and essentially this makes the biggest one of the biggest differences at a relatively low cost is when you make the building airtight and on top of that then you put in the heat recovery ventilation which is a super low energy benefit of maintaining fresh air throughout the building and doing it in a way that you're recovering the heat so if the building is done to a good airtight standard it can and you've got a good ventilation system it can retain up to 95% of the heat and you're running on a really low energy and you've just got a constant fresh air in your building so our house I don't know Jade if you want to go onto a picture oh I should maybe come back to that one so this is where we're now living and we moved our office here over lockdown because it's just such an awesome environment obviously we've got incredible scenery and place to live but the internal environment is fantastic and we don't have any moisture in the house we're yet to put in a an extract because it's a design element that we haven't quite finished yet so that since February and um sorry is this the architect's own house that isn't finished yet right yeah so anyone who's coming to our platform by the light will see a big hole where the extract not in the envelope but a big place but we don't have unless I'm completely immune to it I don't ever feel like the buildings smelling of food and there's literally no moisture it's just a pleasant environment day and night we can go out at night come home in the middle of winter and never think about do we need to how do we heat this house like the house is just warm in the summer because of our the overhang our house is completely north-facing so the overhang here avoids overheating inside and it's just beautiful all the time and it's a lovely place to live and Jade can I just go back to that previous and this one actually yes sorry the one with the thermal bridging that one yeah and so this just to quickly explain thermal bridging so this this is quite a good way of showing what thermal bridging is you've got the blue green areas which is where insulation is on a typical building and then you see what the timber studs do which is a transfer of heat because the stud is not as good an insulator obviously as insulation and if that was steel you'd be looking at red in that place and you can see then what the windows are doing again windows are typically the biggest source of heat loss through the building so essentially your building is consistently losing the heat that you're putting into it which is why it's never warm enough you've got a lot of air that moves around because you've got air heating and then cooling and you it's impossible and especially in this climate to actually heat your building because it just cost too much money if you're not doing something properly so Mike I don't know if you want to explain the product that's shown there. [Shane Clarke] Yeah Mike so just in this slide here what are we um Sian's just touched on the fact that thermal bridging's a no-no and it's something that one of the fundamental principles of Passive House they're trying to avoid and do you just want to touch on what we're actually doing here in that picture on the on the left there. [Mike Skilton] So when we look at that picture it's probably a traditional way that buildings have been constructed in New Zealand when we look at the render on the left-hand side this is more typical of what you'd find in North America and Europe and ultimately this is the concept that we're looking to bring more into play in the New Zealand construction industry the insulation goes on the outside as opposed to in between the studs and what that does is it allows the building to it allows the building to be more usable and provide insulation on the outside of the building that's going to give the best results in terms of the overall envelope performance right so it's obviously continuous across the face of the wall there isn't it sort of eliminating that thermal bridging aspect we've talked about. [Sian Taylor] Yeah Jade could I go through to some of the details and perhaps the detail of this maybe I'll just touch on that graph but just this this one I find really descriptive and just to explain what the heat heating demand is when you start employing all of these things that we just talked about so there are higher levels of insulation good windows air tightness and balanced heat exchange ventilation and so this the taller one is any house that were built sort of pre-2007 when the code changed and then you've got a house which is number four here which is the anything that could be built now and this is this is actually based on our house so one that you just saw and so this would be what our house would be had it been built to building code in this area so you've got a heating demand of almost 150 kilowatt hours per metre squared per annum and that's with a north-facing site where we're catching as much solar gain as we can but you still see such a massive amount of heat demand and then we drop down to here which is what we call a minimum which is what we do as a practise is a minimum we have a premium but then you can see what happens when you come to Passive House so you're pretty much you're down to 15 or below for Passive House so you've gone from 150 down to 15 so you're looking at essentially 10 times less heat demand for that that building and then if I go to the detail perhaps of our house this one here and just very quickly to show some of the products that we use which were through Nuralite so we've got on the roof here we've actually got a warm roof construction and with the Enertherm which is sitting on top of the plywood and this is a sloping roof but we're using a warm roof construction in a sloping roof scenario we've got SIPs panels and then the SIPs panel has to align with insulation which is on the outside of the blockwork retaining wall which is at the back for the lower level we're using the Nuralite tanking all the way down the back of this torch on tanking all the way down the back of this blockwork wall and then under the slab and then on top of the slab for this house we actually use the Enertherm again as our insulation and then we have the timber flooring on top of that so what you can see here is a continuous thermal blanket all the way around the building and no real breaks in that thermal layer. [Shane Clarke] Yeah that's great so I mean if you were to take your red pen to the insulation layer you could basically draw a complete line around the outside of the building including below the ground. [Sian Taylor] Yeah. [Mike Skilton] Sian the one of the big challenges that you have as a designer is obviously the junctions and being able to provide that continuous insulation and removing thermal breaks so there's a lot of thought in terms of passive housing that goes into particularly those junctions. [Sian Taylor] Yeah definitely and minimising complexity is a massive part of that and that's probably one of the two big things that influences our design. Orientation is 100% key if you've got if you've got a site that gives you the north-facing orientation then you know it's like you've been handed something on the plate it's much easier but if you haven't you're always trying to maximise the gain in the way from what's free essentially the sun and avoid it when you don't want it but then second to that minimising complexity because the more that you spread out you know when you're cold you don't open up your arms and you sort of hunker in and more junctions and angles there are like Mike said the harder it is to insulate we know with buildings in New Zealand often you'll see multiple studs next to each other and that's just the way it ends up coming from the framing manufacturer it's super frustrating because it's where you've lost all that insulation and then a corner essentially becomes almost impossible to insulate and often gets covered up before there's any chance to put any insulation in there so as Mike said minimising that is really important. I should go on to this. [Shane Clarke] You're going well for time. [Sian Taylor] So yeah Oliver's Ridge and this place has obviously got a lot of publicity and it was it was huge but for us it came at the end of our first year in practise and it was literally throwing down the gauntlet of everything we had to do. Amazing client and that's where you end up with great architecture and they wanted a building that was low energy and they wanted comfort more than anything. They're Kiwis but they're currently living in Brisbane and they didn't want to be cold and but they wanted awesome architecture and this is a building which is really quite large in scale so we've got a big structure to achieve this this roof here and this overhang but we had to insulate that so every single one of our roofs here is a the Nuralite flat roof and at the time which is now sort of eight no probably six seven years ago it was one of the first projects for us where we would challenge like this and changed almost everything that we do in the way that we think about buildings and Mike was part of that process. We had a much larger team because this is things we couldn't do by ourselves and we relied on people like Mike and Nuralite to help us work out how this was going to work and I know Mike had to go back to Europe to look at how this the interstitial condensation was going to work because we had to put all the insulation on top of the structure yeah this is the detail here this is the insulation on top of the structure and then wrap it all the way around that edge which is the parapet that is cantilevering out and bring it right back to the building line and essentially where you'd normally insulate which is in this big cavity where this big steel is that we've also covered in insulation and that would be typically where you'd have your insulation but we weren't doing that because it was the wrong place to have it we had our air tighteners below the warm roof here and we took the insulation all the way around and back which was quite counterintuitive for us but it was the way that it needed to be done and the team was key to that it's one of the reasons we called ourselves team green and it's using the suppliers and the product manufacturers to help us work out what we've got to do for our region and our climate. [Shane Clarke] Yeah really that's a really good I guess run through on the I guess the fundamental principles of it and even I got a good understanding out of it so you've done well Mike I mean we did a very small part on this project I guess Lincoln you know when you look at the overall project we're just gonna touch on the roof sorry the Nuratherm warm roof system and you give us a bit of a rundown on how that works and how it worked in this particular aspect. [Mike Skilton] Yeah look thanks Shane I'll come to that in a sec but Sian talked on just touch bases on a couple of really interesting things one was poorly behaving buildings and that's a byproduct of the material types that are traditionally used when we're looking at our construction methods you know our materials and systems are really based on science this this passive movement is based on science it's you know it's proving to show that we can you know build beta and that we've got the opportunity of contributing to that with beta quality products one of the reasons why Nuralite's been around in the market for over 54 years is because we partner with fantastic international building manufacturers you know and we represent some of the largest names in the world IKO, Rockwool, Preproof and Bituthene, JM Membranes and they all contribute their part to making to bringing these projects to life and I think that's um you've got a design concept and you've got a client expectations but they're really hard to bring together if you don't have the products to work with and at Nuralite we're very fortunate that we have these outstanding manufacturers that contribute to the story right across the building envelopes that we were involved with in New Zealand we moved our model away but we were traditionally you know the waterproofers the experts in flat roofing waterproofing and then as we've developed our business in the last 15 years we've really pushed this warm roof moving into warm walls moving into warm tanking and as Sian said you know it's about providing that thermal blanket around the whole building and that's really exciting for us we love doing this because we just see it as contributing to making our buildings so much better with what we do so you know when I talk about our system suppliers you know what do they do for us you know we look at our certifications you know fire performance thermal performance compression strength of the boards wind uplift tests zero condensation reports when you're dealing with these types of projects it's really important that you have the suite of products that go with the system you know we see in a lot of cases where people try and you know put blue with red and green and then they hope that it will work and we see a lot of us in the building industry and it's becoming more and more important it's becoming more prevalent that people are just bringing bits and pieces together to hope that they get a system that's not the way that we work we work around our systems based approaches and our warm roof systems our tanking and our outsell action projects so all these things gives this the architects in the homeowners the confidence that they're going to get what they're investing in and it's going to be a long-term solution for these projects. [Shane Clarke] Yeah no thanks for your very in-depth overview on what we do is quite enlightening that is really good and obviously as Mike touched on there actually to one of just to talk to one of the questions that popped through Mike talks about all these bits and pieces that makes up the system now all those bits and pieces or components if you like in our case actually all manufactured from the same manufacturer which is a huge global manufacturer over in Europe they actually make all the components so if you wanted a new light warm roof in Europe you'd be getting exactly the same thing as you're getting here it's not something that we've made up and put together made in New Zealand so to speak right we are running very close to time I've got a couple of questions that have come in from the floor now one of the one of the question I'm going to paraphrase your questions to so excuse me so with the passive house principles are we limited to windows the size of portholes. [Sian Taylor] No I mean you can see I guess looking at this picture but you know that this is not this is not certified passive house and you do have to look at that but you plug all that information into the planning has software and that really helps you with that because you are you do essentially have to look at things like for example West glazing is the killer you've got too much Sun especially in New Zealand especially down here we've got you know Sun till 9 10 o'clock at night in the summer that is blooming hot coming in through that West elevation and that's when the Sun is lower and it's coming right in so it will overheat so you do look at all of that but essentially it comes back to orientation so you're looking at still providing glass where like this what we're looking at here is the North elevation so we want to capture Sun through that elevation and have an overhang to stop the Sun when it's much higher and but now I think that's one of the key things we wanted to show with our company is that architecture is not compromised by employing and the principle that gives you a warm comfortable and healthy building. [Shane Clarke] So the same sort of principles in apply to another question that's come in on a similar topic I guess the same sort of principles applied to the use of actually opening doors and opening windows etc. [Sian Taylor] Basically I mean like I said we're living we're in our house now 24 7 the heating but not heating the electricity bill at the moment's back $50 a month and we get so hot and which it doesn't really get hot but if it's a warm day I just leave all the doors along the front of our elevation open and it's just it's like anything you've got more airflow if you want it but you don't have to you're not reliant on that you can you know it's cold day obviously everything's closed. [Shane Clarke] Yeah right another question here I think this one will be for you Mike there's a do you do hydrothermical sorry hydrothermic calculations. [Mike Skilton] Yes we do so we have some programming that we do use so we would gather the information bring it back and put it through our calculation models and then have that discussion on the on the design concept. [Shane Clarke] Okay cool another question I'm going to paraphrase Sian you talked about the passive house principles are specific to different sites around New Zealand it's not simply a paint-by-numbers and there's some questions here around the type of software or there was a name of the software you use. [Sian Taylor] It's called P8 the shortening is PHPP which is passive house planning package and that's an extensive Excel spreadsheet basically that you plug all the climate data in and all the data about your building and shading and it tells you what it means essentially. [Shane Clarke] Great when this when this webinar is fully recorded this will actually go out with all the Q&A so if we missed the spelling the pronunciation of different words and letters it'll all be there in text for you so another quick question are you constrained to only using timber joinery. [Sian Taylor] No you're not definitely not timber and again it depends where you are it down here where we are you're looking at needing a really good frame so obviously there's other ways that you can do that but and PVC is one which is which is cheaper but it comes with its own but I believe I'm actually I haven't done a passive house in Auckland but I believe you could probably get away with family broken aluminium joinery in Auckland. [Shane Clarke] Okay great all right we're very conscious of your time folks and we do only want to take up half an hour of your time which is generally the time it takes to enjoy a cup of coffee so just while I wrap this up we're going to flick out the second poll just to give us some feedback on the on the presentation today so we can always polish our game make sure we're on top of it so while you're doing that our next our next webinar which is our last one for the year will be a bit of a low-key walk through the Nuralite operations here and meeting a few of the individuals and basically showing you the premises and what we do and sort of a I guess behind the scenes I guess almost bloopers reel really and the last poll will be basically would you like a follow-up from today's presentation so you work on something specific at the moment you'd like a follow-up from either the Nuralite team or the team green team so if you pop your answers in there one of us will be able to get back to you on that so yeah just a quick recap again thank you all the participants we believe we're doing some really good things here with some of the charities and even just for attending you've made the world a better place so good on you today we covered off the fundamental principles of passive house design which is basically wrap it tight and ventilate right if I nutshell that and like I say if anyone wants to follow up put it into the poll there we'll be able to come back to you and we'll be seeing you all next week with the last webinar and just before I go big thanks to the panellists Mike thank you Sian and big thanks to producer Jade behind the scenes all right we'll leave you with that thanks very much guys.