the high-performance housing magazine
sUMMER 2015
residential winner
2015 canadian green building awards
Beechwood deep energy retrofit
Urban Straw Bale Reno Renewed Tudor-style home gets energy cut
RIGID FOAM PANELS Not all the same
THE ECOHOME DEMO HOUSE
Stage three: efficiency with heat pumps ecohouse CANADA | SUMMER | 2015
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The national source of information on Canadian sustainable high-performance homebuilding in partnership with www.ecohome.net.
sUMMER 2015 6
THE ECOHOME DEMO HOUSE STAGE three Increased efficiency with heat pumps
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house in low
Study shows there is more to thermal performance
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AWARDS
residential winner 2015: Beechwood deep energy retrofit
23 urban straw bale reno
PR O J E C T G BUILDING N
Beyond R-Values
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T IA L W E N N G I NN D RE I DIA E A
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Off grid, passively-heated home achieves LEED Gold
Renewed 90-year old Tudor-style home gets big energy cut
27 Energy evaluations
How they can guide a renovation
29 RIGID FOAM PANELS NOT ALL THE SAME Where they are best used
SEE MORE at • www.sabmagazine.com u click on ecoHouse Canada • www.ECOHOME.NET Cover: Beechwood house. Photo: Greening Homes Ltd.
ecohouse CANADA | SUMMER | 2015
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1-888-4DELTA4 (433-5824) - www.cosella-dorken.com 4
ecohouse CANADA | SUMMER | 2015
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The winning projects Eight high-performance, sustainably-designed buildings [seven commercial/institutional and one residential], all awarded in the 2015 Canadian Green Building Awards, point to a future in which the buildings where we live and work will be far superior to what we know today.
Launched in 2008, and offered annually by the Canada Green Building Council [CaGBC] and Sustainable Architecture & Building [SABMag] and ecoHouse Canada, the Awards recognize excellence in sustainable, high-performance building design in order to advance knowledge and improve practice for the design of nonresidential and residential buildings. This is amply demonstrated in the winning residential project, the Beechwood Deep Energy Retrofit by Greening Homes Ltd. in Toronto featured in this issue, a post-World War II bungalow transformed into a highly-efficient two-storey home: a retrofit that exceeds Passive House air-tightness requirements for new construction. The central message of the Beechwood project is that we have the knowledge and products to make our houses much more energy efficient and with healthier indoor air quality than the houses which we are building, and for about the same cost, especially if building new. Publicising high-performance housing is the purpose of ecoHouse Canada, which is why we became involved in the Demo House Video Building Guide, a 20-part series on the techniques and products for building high-performance housing in the Canadian climate. The first five videos can be seen here: http://www.ecohome.net/video/guide. The annual Green Building Awards gives us a look at a promising future. We thank our sponsors Interface, the Canadian Precast Prestressed Concrete Institute and Uponor without whom the 2015 Canadian Green Building Awards would not have been possible.
ISSN 1920-6259 Copyright by Janam Publications Inc. All rights reserved. Contents may not be reprinted or reproduced without written permission. Views expressed are those of the authors exclusively.
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Please forward comments, article ideas and project contributions to: Don Griffith, Publisher dgriffith@sabmagazine.com - 1 800 520 6281 ext.304
Environmental savings for this issue:
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14 Trees
52,769 litres water
799 kg waste
2,078 kg CO2 ecohouse cANADA | SUMMER | 2015
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Td he em eo ch o ho ou ms ee update
STAGE Three Increased efficiency with heat pumps working in tandem
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Our previous update covered aspects of the building envelope which allowed us to reduce the annual heating requirement to about the Passive House standard of 15 kWh per square metre. Windows are a part of that but they are also part of our energy performance strategy. The house is laid out south facing to maximize passive solar heat gain, so we have designed and chosen windows to take best advantage of that. By Mike Reynolds
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Window glazings on the north, east and west have an R value of 8.4, but intentionally only R 6.4 on the south, due to different Low E coatings. Low E coatings reduce heat loss, but they also reduce heat gain. By sacrificing that 30% of the insulation value on the south side, we were able to increase the amount of passive heat gain we would have by 80%. In houses that perform at this level of efficiency, domestic hot water becomes the single biggest consumer of energy. To tackle that, we have two heat pumps which together will reduce that energy demand dramatically. A Mitsubishi ‘Mr. Slim’ split heat pump will provide heat to the house; we also have a heat pump water heater from AO Smith. The Mr. Slim operates efficiently down to -25 °C at close to a 3 to 1 ratio of consumption, meaning three units of heat out per unit of energy in. That is three times more efficient than a standard electric baseboard heater which offers you only a 1 to 1 ratio. The AO Smith water heater is an air-to-water heat pump which extracts heat from the air to generate hot water, so in the winter that 3 to 1 heating ratio of the first heat pump is transferred to the water heater. And the more ‘free’ heat you have in winter [solar gains and general occupancy] the more efficient it becomes. In the summer it acts as an air conditioner as it extracts heat from the air to generate hot water, in a way giving you ‘free’ hot water, since rather than ejecting heat from your home as most air conditioners do it is retained in the form of domestic hot water.
Since two-thirds of the bulk energy consumption in a home is usually a result of heating, with our building envelope we’ve been able to reduce that to about 10 percent of what most new homes require. Beyond that, the next big leap in efficiency comes from reducing interior loads. Heat pumps are a great way to do that, particularly with hot water. Our heat pump combination together is surprisingly affordable, and it has taken a big chunk out of the total energy required for the operation of the house. To get a better look at what we’ve got going on so far and some of the fancy features still to come, check out the Ecohome Building Guide at ecohome.net where you can see the first five videos in the series. When complete the Ecohome Building Guide will document the entire construction of the house. We thank our product sponsors: Roxul, W.R. Meadopws, Kott Lumber, Uponor, Ecogenia/Lunos, CGC, Fantech, Delta [Cosella Dorken], Mitsubishi Electric Canada, American Standard, Benjamin Moore, A.O. Smith, Riopel , Columbia Forest Products, Les Fenêtres Élite Inc., Cosentino Canada, Glendyne, Isocork Canada, Rainfresher, Bostik and Aeratron.
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The south-facing windows have a lower Low-E coating to allow for more passive heat gain in the winter [1]. The components of the Mitsubishi ‘Mr. Slim’ split heat pump which will provide heat to the house with three times the efficiency of baseboard electric heaters [2]. The AO Smith water heater is an air-to-water heat pump which extracts free heat from the air to generate hot water [3].
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news
Housing development aims for 28% energy savings In its new development of 185 homes in the Region of York near Toronto, Mozaik Homes is participating in a pilot project which is anticipated to achieve 28% energy savings based on the model that was created in collaboration with the Savings by Design program. A conservation program offered by Enbridge Gas Distribution to residential and commercial builders, Savings by Design assists in obtaining higher levels of performance through the application of the Integrated Design Process [IDP]. Facilitated by Sustainable Buildings Canada, builders and developers participate in an IDP workshop to understand how to improve energy and environmental performance. Info: www.savingsbydesign.ca.
BOOKS Sustainable Residential Architecture by Ana Maria Alvarez Reviewed by Jeffrey Thorsteinson Head Writer & Researcher, Winnipeg Architecture Foundation and Republic Architecture Inc.
As a term, if not in practice, sustainability is everywhere. Tossed around liberally, the word is an all-but necessary ingredient in building proposals, political statements and the like. The ambitions embodied in this practice are good. But omnipresence can create meaninglessness, a dire truth given that so much
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remains unsustainable. To be more than a platitude sustainability must go beyond the superficial, must even disrupt. Enter Ana M. Alvarez’s Sustainable Residential Architecture. Heavy and gleaming, the book appears to be exactly what’s needed: an in-depth exploration of sustainable architecture that gives the real thing mass appeal. But while a picture is worth a thousand words, sometimes you need a paragraph. On that count this book falls short. From its scant introduction to barelythere project descriptions, Alvarez’s text is so thin as to leave us guessing as to what makes these buildings sustainable. Without much on which to base a reading, what stands out is what’s missing, including heritage re-use and multi-family residences. Some lovely works are included, notably Wolfgang Feyferlik’s Stockner House and FLOAT Architecture’s Oregon Watershed – a positively Thoureauvian retreat. But as a view of sustainable architecture, the book is limited, featuring single-family homes and cottages less alluring but comparable to an average shelter-mag. Sustainability goes beyond shipping containers and pre-fabrication. Lovers of true sustainability will have to look elsewhere. 400 pages, Hard cover wirh jacket, $45.00 EAN: 9781770854475 ISBN: 1770854479 www.fireflybooks.com
Acclaimed architect Peter Busby’ s new book shows a future where buildings and cities contribute to nature Peter Busby, the award-winning architect and winner of the 2014 RAIC Gold Medal, has been an innovator in sustainable building design since opening his architectural practice in Vancouver over 30 years ago. In his new book, Busby: Architecture’s New Edges, he directs his experience and observations to forecast a future in which architecture will create buildings and cities that will sustain life. Busby now works in the upper levels of international firm Perkins+Will which is perhaps THE leader in sustainable design and thinking. Some of the issues covered in the book are: Culture of Innovation: Fostering Ingenuity; Regenerative Design: Architecture Finds its Place in Nature; The Future of Cities: Sustaining Life; and The Future Face of HighPerformance Design. Peter Busby’s message is clear: “the architect can become an agent of change, capable of building things that guide others toward more responsible behaviour”, [but] ”We can-
not in good conscience exhort our clients to do things we ourselves would not do.” Busby walks the talk like few others in the sustainability movement - and ‘Busby: Architecture’s New Edges’ exhorts every one of us to do the same.
262 pages, 9”x11” 262 pages fully illustrated in colour, $49.95, ISBN 978-0-9827749-3-9 https://living-future.org/ecotone
PASSIVE HOUSE CONFERENCE October 1 and 2, Vancouver North American Passive House Network conference [NAPHN15] Hosted by the Canadian Passive House Institute [CanPHI] West at the Hyatt Regency hotel in Vancouver, the NAPHN15 conference features case studies of exciting Passive House developments, from low rise to high rise, in hot and cold climates, from North America and around the world. Workshops and presentations will be curated for those new to Passive House, and for others looking to deepen their knowledge. The two-day conference will focus on three key areas of Passive House design and construction: An Introduction to Passive House, Advanced Passive House Techniques, and Policy and Regulation. There will also be a trade show dedicated to exhibitors in the Passive House market. Post-conference tours in Vancouver and Whistler/Pemberton will showcase Passive House projects including a prefabrication plant and a public recreation facility. More details: http://naphn15.canphi.ca
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House in Low Off grid, passivelyheated home achieves LEED Gold
North elevation
When you’re a long way from the amenities of civilization, employing both active and passive solar strategies can provide security, independence and just good living in general. By Hillary Hosta
South elevation
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2 With their house near Low, Quebec, about three kilometers from the nearest paved road and hydro pole, Craig Anderson and FrancePascale Ménard had no option but to go for extreme efficiency in design, product selection and construction if they wanted to achieve LEED Gold. Built by Bala Structures of Wakefield, Quebec, and designed by Anthony Mach of Mach Design, Craig and FrancePascale went after that LEED Gold certification and got it. The LEED system generously awards points for the type of transportation and service connectivity found in urban cores, so if getting yourself home requires the opening and closing of cattle gates, you’re not likely going to pick up points for being close to public transport. If despite your remote location, you still end up with a LEED Gold plaque on your wall, you’ve definitely gone the extra mile in designing your home for healthy, sustainable, efficient living. The design for the house began with the basic principles of passive heating and cooling - invest in quality windows, face as many of them south as you can to maximize heat gain and utilize heavy duty insulation to capture that heat in the winter months.
Design Mach Design Construction Bala Structures Photos Bala Structures
4 Without blocking the low winter sun from entering, a large overhang and sun shades keep the high summer sun out to prevent overheating. This family also enjoys the comfort of supplementary heat from the wood stove and radiant floors, warmed by a propane boiler. A double exterior wall system helps to reduce heat loss to a fraction of that being lost by most other new homes being built today.
Exterior wall composition - from inside to out: • Gypsum board with zero VOC paint; • 2x4 stud wall at 24” centers as wiring chase, with R14 mineral wool batts; • polyethylene air/vapour barrier; • 2x8 stud wall at 24” centres with R28 mineral wool batts; • 1-1/4” exterior mineral wool board, R5; • plywood sheathing; • house wrap; • strapping; • cement board siding.
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Building section: double wall construction and highly-insulated roof
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The benefits of a double exterior wall are plenty. This type of building envelope eliminates thermal bridging through studs, provides a lot of room for insulation, and the air/vapour barrier is sandwiched between walls where it won’t need to be punctured for electrical work, as all wiring is done on the interior 2x4 wall.
Within the circle of high-performance home construction, an effective R36 wall falls pretty much into what is known as the ‘sweet spot’ of design, meaning the optimum balance of energy efficiency and cost effectiveness, by investing in insulation instead of heat generation.
Not punching a ton of holes in your air barrier allows it to do what it is intended to do - stop air leakage - which commonly accounts for about a third of the heat loss of a home and creates significant risk of moisture damage inside walls.
Active Solar and Energy Efficiency
The ceiling is a mix of mineral wool batts and cellulose, totalling R80. The basement is a mix of EPS foam and mineral wool batts totalling R28. The insulating value of the wall adds up to R48.8 in total, which is about twice that of most provincial building codes. With framing materials factored in, energy modelling shows the effective or ‘true’ R value of the wall is 36.3. With heat gain from the sun and an airtight building envelope, the energy required to keep this house warm will be a fraction of what most houses use.
Large south-facing windows allow solar heating in the winter while a generous roof overhang and and sun shade prevents over heating in winter [1]. The south and east elevations [2]. The stair to the basement where the bedrooms are located and have windows along the south side of the house [3]. Energy-efficient appliances are essential in a PV-powered home, as are highly insulated walls and roof [4].
The house is also powered by solar panels. When you rely on an array of photovoltaic [PV] panels to power your home there is an even stronger motivation to design that home with optimal efficiency in mind. Energy-efficient appliances and low-flow faucets reduce hot water requirements. With an emphasis on natural lighting, augmented by strategically placed LED bulbs, the house is kept bright with very little energy use. After living in the house for some time, Craig Anderson said - “It feels different to live in a house that is both actively and passively solar powered; the path of the sun and the weather are central to our experience of living in this home. With the house situated perfectly on a solar east/west axis, we get the rising and setting sun shining through the length of the house on the spring and fall equinox. I know exactly when noon is without referring to a clock, as the sun is shining straight in from the south windows.” They also report needing to open windows as early as March when the days are warmer and brighter but the sun is still low in the sky and describe this as a “nice problem to have”. Having lived in the house for a while, the owners are planning some upgrades: • A small portable backup generator • Additional PV modules to augment power supply. Changing the angle of the PV modules from 45 degrees to 65 or 70 degrees to eliminate the need for snow removal and accommodate more of the low-angle winter sun.
Basement
• Remote monitoring by using a cellular modem they connect to the internet while off-grid, enabling them to monitor their house from afar. Battery levels, generator stops/starts, pauses, even the temperature of their home is available to them wherever they are. Alerts for any kind of mechanical failure can also be set. It’s easy to see how this beautiful home, with its high-performance and passive design scored LEED Gold despite its remote location. v Hillary Hosta is a sustainable design enthusiast, writer and contributing editor to ecohome.net
First floor Floor plans
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You’re invited …
to the Demo House Video Building Guide One of the best information sources on techniques and products for building high-performance housing in the Canadian climate. View the brief, informative videos, and return often as we add more.
http://www.ecohome.net/guide
A project of ecohome.net in partnership with ecoHouse Canada.
and
Canadian Directory OF Sustainable PRODUCTS SERVICES Find products and expertise for high-performance building http://sabmagazine.com/product-directory.html A dynamic web section for all your green building information
SUSTAINABILITY NEWS SUSTAINABLE ARCHITECTURE & BUILDING MAGAZINE
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2015-07-06 1:53 PM
Beyond R-Values Study Shows There is More to Thermal Performance
The thermal performance of wall assemblies and insulation products has long been characterized using R-value, a metric which describes thermal resistance. While R-value is useful, it doesn’t tell the whole story about heat flow through building enclosures such as walls and roofs. Recently, a study by RDH has shown that real world thermal performance depends on a large range of factors including temperature, age, thermal mass, and surface reflectance.
By Lorne Ricketts
photo: Test roofs used to measure impact of three different roof membrane colours
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Insulation Properties: Temperature, Age, and Thermal Mass Typically insulation R-values are measured at a mean temperature of 24°C [75°F] and a temperature difference of 28°C [50°F], but this doesn’t necessarily match with the temperatures experienced in service. Roofs, for example, can be expected to experience a range of temperatures from -10°C [14°F] to over 80°C [176°F], even in a relatively mild climate. To assess the impact of temperature on two types of insulation [polyisocyanurate and stone wool], measurements of R-value per inch were made over a range of different temperatures more characteristic of in-service temperatures. [i]As shown in Figure 1 these measurements found that the R value of both insulation types change with temperature, with the polyisocyanurate [polyiso] demonstrating a more significant response.
The polyiso insulation provides close to its rated R-value when measured at 24°C [75°F], but at both lower and higher temperatures the performance decreases dramatically. Importantly, it is at these more extreme temperatures [i.e. farther away from interior temperatures] where the performance of the insulation is most needed, and yet it is at these temperatures where it performs worst. Notably, the R-value of the polyiso also depends on the age of the insulation. This well-known effect is caused by gasses from the manufacturing process slowly diffusing out of the insulation as it ages, and is commonly captured using the long-term thermal resistance [LTTR] metric, but also exaggerates the effects of temperature.
figure 1: Insulation r-value per inch at range of temperatures
A recent study by RDH which looked at conventional roofs found that the thermal mass of the insulation, in addition to the assembly itself, can also impact in-service heat flows. Thermal mass stores heat energy and provides a buffering effect. For example, a roof insulated with stone wool takes longer to heat up when exposed to the sun in the morning and longer to cool down in the evening than would a roof insulated with a less thermally massive insulation.
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This buffer effect can reduce the temperature difference across enclosure assemblies and reduce in-service heat flows. These changes in in-service performance as a result of temperature, age, and thermal mass can significantly impact the actual heat flow through a building enclosure in comparison with what would be predicted by considering only the rated R-value.
figure 2: annual heating and cooling energy consumption
Exterior Surface Colour
The Big Picture: Energy
Significantly, the properties of the insulating materials are not the only factors which affect in-service heat flow through building enclosures. For example, the exterior colour [i.e. solar reflectance] of the surface of an assembly can have a significant impact on the surface temperature, which in turn can impact the amount and direction of heat flow. For example, dark roofs typically absorb more solar energy than do lighter roofs. On a sunny day with 25°C [77°F] ambient air temperature, three adjacent black, grey, and white roof membranes on the same building [see photo] were measured to have maximum surface temperatures of approximately 75°C, 65°C, and 50°C [167°F, 149°F, and 122°F] respectively.
While insulation R-values are important, what really matters is energy consumption. To assess the impact of different roof insulation types on whole building energy performance, energy modelling was conducted of a building with roofs having the rated insulation R-value required by the ASHRAE 90.1-2010 energy standard for each climate zone. In addition to the rated R-value, this modelling then also took into account the temperature dependent R-values of stone wool and aged polyiso insulation, their different thermal masses, and the colour of the roof surface. [ii]As shown in Figure 2, this analysis demonstrated how the impact of each of these factors on the heat flow through enclosure assemblies subsequently affects building energy consumption, with different combinations providing optimal performance depending on the climate.
While typically in cold climates we think of increased R-values as preventing heat loss from the warmer interior to the colder exterior, in some cases R-value can actually prevent potentially beneficial heat gain from a warm surface, such as a roof. The optimal balance of preventing heat loss and allowing heat gains will depend largely on climate, assembly arrangement, and building use. In the future it may be possible to design optimal surface colours [i.e. reflectance] and insulation combinations to minimize building energy consumption, though increased insulation will probably be the best option in most cases. [i] All measurements made at 28°C [50°F] temperature difference at ASTM C1058 recommended mean temperatures. [i i ] Note that a simplification is made here as the temperature dependent R-values also depend on thickness of the insulation sample, but this was not taken into account as part of this analysis.
Overall, as big picture concepts of thermal performance and energy efficiency are addressed, it will become more important to consider the finer points of insulation product and assembly performance as these considerations can impact the energy performance of buildings. v Lorne Ricketts is a Building Science Engineer [EIT] with RDH Building Engineering Ltd. and has significant experience with the thermal performance of building enclosures and insulation products. He was the lead investigator on a recent project by RDH which assessed the thermal performance of conventional roof assemblies and is actively involved with several research and new construction projects.
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Beechwood Deep Energy Retrofit Post-World War II bungalow re-made for healthy, low-energy living By Steven Gray
This deep energy retrofit began with an uninsulated masonry bungalow located on a ravine lot with favourable solar orientation. The owners’ goals were to build an energy-efficient home with great indoor air quality and low water consumption while being respectful of their environmentally-sensitive site and integrating seamlessly with the surrounding building fabric. The resulting building, when modelled using Passive House software, has an annual heating demand of 30kwH/m2, approximately 65% less than a code-built home of equal size. Most remarkably for a retrofit project, the home achieved an air tightness level of 0.44ACH @50Pa. The main floor was completely opened up for more natural light and space flow [1]. The second storey was added for better energy efficiency and for less site disturbance [2].
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Standing seam cool metal roof
Garage deck
Natural cedar soffit Fiber cement siding
Site plan
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South elevation
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AWARDS
2015
The winning residential project of the 2015 Canadian Green Building Awards is a post-World War II bungalowtransformed into a highlyefficient two-storey home: a retrofit that exceeds Passive House airtightness requirements for new construction. The project underwent an integrated design process involving the architect, sustainability consultant, mechanical engineer, builder, and other professionals from the high-performance building industry.
Original house and outline of addition
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R50 - 1'' polyiso on interior ceiling + mineral wool batt on flat roof area
R63 - 1'' polyiso on interior ceiling + 15" blown-in cellulose R43.6 - 4'' polyiso on exterior with 3'' of 2lb foam on interior
U 0.14 - triple glazed fiberglass windows with insulated frames R43.6 - header cavity filled with foam + 4'' polyiso on exterior R43.6 - 4'' polyiso on exterior with 3'' of 2lb foam on interior
R57 - 4'' polyiso on exterior of bay with 8'' of mineral wool in 2x8 stud cavity
R43.6 - basement above grade with 4'' polyiso on exterior and interior foam
R30 - below grade basement walls 5'' 2lb foam
Insulation Insulation design
R20- under slab and around perimeter of slab
All joints on interior oriented strandboard [OSB] strapped ceiling are taped and no penetrations into attic Transition strip between exterior taped sheathing and interior OSB strapped ceiling
All joints on exterior nail base OSB insulative sheathing are taped
Expanding foam tape + U Shims + flashing tape on all windows and doors
Transition strip between interior and exterior taped OSB
Joint compound and mesh tape at existing floor joists that are embedded in masonry
Fluid-applied air barrier on interior of existing brick 1st floor walls
Fluid-applied air barrier on interior of existing foundation
Interior water-proofing membrane with all penetrations taped Air barrier diagram Air barrier line [0.44 ACH @ 50 kpa]
10mil poly sub-slab air barrier, all seams and penetrations taped
Future hybrid thermal PV array Solar deflection
Solar shading and deflection
Passive solar gain
Radiant ceilings
Radiant slab Heating and cooling delivered hydronically via radiant ceiling panels and basement slab [coloured zones]
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The project was developed through an integrated design process incorporating Passive House design principles: building geometry and glazing were optimized for passive solar gain during the heating season and solar exclusion during the cooling season. Super-insulation, thermal-bridge-free construction, an airtight building envelope, and mechanical ventilation with energy recovery serve to minimize space conditioning requirements. Heating and cooling are supplied by a heat pump; which uses a shallow geothermal loop - and in future, solar thermal panels - to collect or reject heat. Distribution to the home is via radiant ceilings for greater efficiency and superior comfort. As proof of concept, no supplementary heating was required during the first winter of occupation, despite temperatures dropping as low as -2 oC. The 300-foot lot extends into the Don Valley, an environmentally-sensitive area regulated by the local conservation authority. A large existing deck required replacement, and the homeowners decided to reduce the footprint in order to limit the impact on the ravine. Helical piles were selected to support the structure instead of conventional concrete piers to avoid disruptive excavations in sloped areas. In order to reduce runoff from the property, and reduce the potential for erosion in the valley, the home is plumbed to collect rainwater in a cistern buried under the front lawn. By way of a separate supply manifold, this water will be recycled for non-potable uses such as irrigation, toilet flushing and laundry. To reduce overall water demand, the Beechwood home has low-flow plumbing fixtures and dual-flush toilets in all three bathrooms.
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View opposite to that of photo 1. The clerestorey window helps with natural ventilation and more natural lighting [3]. Heating and cooling is through radiant heating panels in the ceilings [4].
Blown-in cellulose Transition strip between exterior air barrier and interior ceiling OSB
Taped transition between exterior nailbase and ceiling polyiso 1” polyiso insulation 4.5” exterior polyiso nail base with sealed joints and fasteners
4” 2lb spray foam insulation 2lb spray foam Tape at seams and joints
Membrane transition under new sill plate with tape at interior seam with fluid-applied air barrier and 3M tape and exterior seam with OSB Fluid-applied air barrier membrane at interior of double wythe brick wall
4” XPS taped at seams
4” spray foam insulation
Nailbase with rigid polyiso
2lb spray foam insulation 4” XPS rigid insulation under slab
Fluid-applied air barrier membrane at cmu foundation DELTA®-MS damp proofing membrane, taped at seams with tape Hydronic radiant floor heating in slab
10mm poly vapour retarder taped at seams with tape 6” crushed stone Shallow geothermal loop Building envelope details
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Garage Bedroom Dining room Living room Kitchen Bathroom Great room Pantry Storage
Closet Entry Living space Mechanical room Entertainment area Home office Utility Study
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After Existing to remain New walls Ground floor
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Second floor, new
Existing to remain To be demolished Basement
Project Credits General Contractor Greening Homes Ltd. Mechanical Engineer and Energy Consultant Sustainable EDGE Architect Open Architects Landscape Architect Sunarts Design Non-potable Water System Design Rivercourt Engineering Integrated Mechanical System Installation Adymo Photos Greening Homes Ltd. Materials
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Jury comment: A highly transferable example of how to intensify existing communities, adding to their capacity and improving their energy performance. The ambition to take this rather unremarkable existing house to an exceptionally high level of energy performance is to be applauded, as is the suite of innovative but highly transferable strategies that were used. It is also noteworthy that the project team decided to build upward rather than outward, and to restore previously paved areas of the site to natural landscape.
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FSC-certified framing lumber; DELTA®-MS, The Foundation Wrap, below grade foundation protection for masonry and poured concrete structures; triple-pane, argon-filled, fibreglass windows by Fibertec, 40% SCM content concrete; rigid foam exterior poliyiso ‘Nailbase’ insulation; spray foam insulation; Watersense-certified dual-flush low-flow toilets; high recycled content drywall; low-VOC paints; LED lighting; fibre cement siding, metal standing seam roof; energy recovery ventilator, heat pump with radiant heating installed in the ceilings.
The 2015 jury [left to right]: Megan Torza, Partner, DTAH; Darryl Condon, Hughes Condon Marler Architects; John Crace, Architecture49; and Braden Kurczak, formerly of MMM Group Limited [5].
The energy conservation strategies and systems used on the project include: ´ a water-to-water reversible heat pump that uses multiple heat sources and sinks ´ a shallow geothermal loop located below the sub-slab insula- tion that serves as a heat source/sink ´ heating and cooling delivered hydronically via radiant ceiling panels and the basement slab ´ a high level of airtightness [0.44ACH @50Pa] ´ a hydronic coil that conditions ventilation air before it is distrib- uted to the house and provides additional dehumidification in the summer ´ an energy recovery ventilator [ERV], and ´ drain water heat recovery
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Prior to completion, the home was part of OSEA’s Green Energy Doors Open event. This event saw over 125 attendees learn about the systems in the home and how it’s different from standard construction. Now that the project is complete, the owners remain committed to using their house as a teaching instrument; conducting tours of their home for engineering and architecture students from U of T and Ryerson. The home has already been the subject of a seminar on high-performance building and future seminars focusing on post-occupation performance are scheduled for 2015. v Steven Gray, M.Eng, P.Eng, CPHC, LEED AP is construction manager at Greening Homes Ltd.
The new second floor with study and bedrooms. Fibertec windows Were selected for their insulated fibreglass frames manufactured locally in Toronto, and with an exterior moulding that facilitated air sealing and exterior finishing, while placing the insulated glazing unit in the insulation plane [6, 7 and 8].
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Considerable emphasis was placed on the retention of existing materials and components where possible, and the sourcing of reclaimed materials and equipment. The existing masonry and original floor joists of the home were maintained. All appliances, doors, boiler and radiators were donated. The waste diversion rate achieved was 80%, including all demolition. Among the materials used were: FSC-certified framing lumber; lead-free brass plumbing fittings; triple-pane, argon-filled, fibreglass windows; 40% SCM content concrete; Watersense-certified dual-flush low-flow toilets; high recycled content drywall; low-VOC paints; recycled denim batt sound insulation; regionally-sourced maple flooring; and LED lighting throughout. This low-energy home offers the prospect of healthy and affordable living over the long term, independent of any fluctuations in energy prices. The owners want to share the lessons learned with their community.
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Urban Straw Bale Reno
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Renewed 90-year old Tudor-style home gets big energy cut Air tightness, improved insulation, new windows, reduction of thermal bridges, and ventilation based on Passive House principles reduce energy consumption by nearly 80%.
By Terrell Wong The graceful 90-year old masonry Tudor-style home, sitting mid-slope between the road in front and a laneway behind in the Beach area of Toronto, had changed little since its original construction. To honour this history, the beautifully panelled living and dining rooms were restored, and the spaces which wrap around these original rooms opened up. A full-width twostorey addition was constructed at the rear to create an open-concept kitchen and family room which look out into the lush sloping backyard through triple-glazed fullheight windows.
For longevity and life cycle costs, passive solutions surpass technological ones.A priority of the design was the continuation of the existing exterior stucco with the same robustness of the original masonry/ lime render construction but with a higher thermal resistance. Straw bale not only fulfills the structural but also the thermal and finishing requirements of the building. Straw bale is a double diffusion thermal mass system with the equivalent of R30 insulation. It is also economically more viable than solid masonry, and muchmore durable than stucco over a wood substrate. Although the original living and dining rooms were left intact, the entry and stairs of the original home were completely opened up with the new stairs extending into the basement allowing for natural light penetration from the back, front and side of the home. The entire house is within 7m of an operable window. Existing windows along the side of the building that had been covered over were restored to bring light deep into the interior.
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Regulatory challenges Occupant health from toxic materials is not as high a priority in the Ontario Building Code as physical safety. Because of liability concerns, building code administrators emphasize manufactured goods with CCMC testing over natural materials. Terms such as lime render or straw bale are not found in the code. Even though the City of Toronto owns its own straw bale building our application for permit was denied in December, 2013. The problem is that city governments feel that the province has downloaded liability to them by implementing the Alternative Solutions option for materials and systems not found explicitly in the building code. Even though the Ontario Ministry of Municipal Affairs and Housing wrote the Transition Training for the Objective-Based 2006 Building Code, which says [Page 5-2]: “An example of a proposed equivalent system could be a wall system of straw bale construction, “ municipalities have to assume liability so their building examiners usually direct people away from Alternative Solutions. We launched a campaign to have our alternative solution application accepted and succeeded in obtaining our full permit in June 2014.
Nudging the straw bales with a wooden mallet, and using a grinder to trim off the excess straw [1]. Construction progression of the rear strawbale addition [2]. The restored front and new rear addition [3 and 4]. The interior of the existing house was completely re-insulated and finished, including FSC-certified oak flooring, and triple-glazed windows [5 and 6]. The restored master bedroom and adjoining den. The original radiators were re-located and re-used [7].
A solar tube brings natural light into a centrally located bathroom. A system of layered lighting with dimming options maximizes the flexibility of the lighting system. LED lighting is used throughout the house. A passive house approach was used to reduce the energy requirements by 80%. In order of importance: air tightness, insulation, thermal bridging, windows and mechanical ventilation were targetted to meet our energy targets. Firstly, we reduced air infiltration from over 13 ach [air change per hour] down to 1.5 ach at 50 Pa. Then we concentrated on insulation levels throughout the existing and proposed portions of the house: R30 minimum for the walls, R20 below the basement slab, R40 below the addition slab, and R60 in the roof. Triple-glazed, wood-clad aluminum windows and doors were installed throughout the house. A 94% efficient fully ducted energy recovery ventilator [ERV] completes the passive house approach to energy reduction. 24
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The heating system is a hybrid of redistributed radiators and an in-floor system in the basement and kitchen slabs powered by a 95% AFUE condensing gas boiler. The thermal mass of both the existing and the addition should be able to cope with several consecutive days of high temperatures. Lime render has been shown to moderate humidity levels for consistent comfort within the building. Projected total heating and cooling/ m2a [megajoules consumed per square metre home area, in a year] is 246MJ, which is about 60% less than an average house.
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Materials and Life Cycle
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Natural or non-toxic materials were chosen throughout the entire process, but they also had to stand the test of time to create patina, not degradation. The low-embodied energy natural materials like wood, straw bale, lime render, and lime plaster were crucial to the material matrix of the building. All the interior walls were finished in lime plaster as it is very durable and does not require a painted finish. New gypsum board has 99% recycled content.
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Basement Floor plans - shaded area shows new construction
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BASEMENT PLAN SCALE: 1:80
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Recreation Laundry Mechanical Unexcavated Living
Entry Porch Dining Family room Kitchen
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Den/wardrobe Bedroom Deck
Exposed ceiling ties clad in oak to match floor
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Screw-adjustable deck pedestals supporting cedar deck boards
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Cellulose insulation at floor-wall intersection
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Textured lime render base colour matched to existing brick Ground floor
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GROUND FLOOR PLAN SCALE: 1:80
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- Engineered wood floor - 4” reinforced concrete slab - 12” perlite insulation - 4” gravel - Compacted fill Existing stone landscape wall
4’-deep ICF foundation with peel and stick termite barrier
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Section through rear addition
12 The original stairs were completely opened up with the new stairs extending into the basement allowing for natural light penetration from the back, front and side of the home [8]. The new kitchen on the ground floor of the straw bale addition [9].
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SECOND FLOOR PLAN SCALE: 1:80
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Vapour barrier paint over GWB
Project credits Architect Stone’s Throw Design Inc. Construction The Fourth Pig Worker Coop Mechanical Engineer Renu Building Science Structural Engineer Building Alternatives Inc. Commissioning Blue Green Consulting Group Photos Riley Snelling
Plywood over top of strawbale wall extend out to edge of soffitt and caulk at lime render
MATERIAL Straw bale construction for rear two-storey addition with lime plaster used as interior finish and exterior finished with breathable silicate paint; refurbished original house insulated in the roof with HeatLok Soya 2lb spray foam insulation by Demilec [targetting R60], and combination of HeatLok Soya spray insulation and Ultra Touch denim batts [from distributor Twin Maple] for the walls; air barrier sealed with SIGA tape distributed by Eco Building Resource; drywall with 99% recycled content, triple-glazed aluminum-clad wood windows installed on the street side custom leaded in the original Tudor style; new boilers and existing radiators relocated and used, in-floor radiant heating in new construction.
Straw bale: an air tight vapour permeable wall system also known as ‘vapour open’ or ‘double diffusion’
Air sealed window fastened to plywood box frame using air-seal tape 1” thick lime render finish 6ml poly taped seams under concrete slab
Plywood around window and door openings; air-seal tape around windows and doors
Custom prefinished aluminum sill with continuous drip edge
Section, new rear wall
Vapour barrier Air barrier
8 9 ´ The original wood trim and doors were catalogued and reused throughout the building, and the original radiators were refurbished and reused. ´ The existing kitchen cabinets were reused in the basement laundry room. ´ Many of the lighting fixtures were pre-owned. ´ A steel beam, taken from another heritage project, was used in the kitchen as a column. The contractors recycled all of the paper, metal and plastics. Our contractors routinely salvage wood, bricks and other usable materials from demolition for reuse in construction. The renovation gives the house a second life, and we anticipate that this type of reconstruction could occur in another 100 years. By limiting complex technology and concentrating on the thermal envelope, we reduced lifetime maintenance costs. Removing everything other than structure and insulation from the exterior walls will allow any future interior changes to not adversely affect the thermal envelope. v Terrell Wong is principal at Stone’s Throw Design Inc.
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Energy evaluations
can guide a renovation A major renovation, such as finishing a basement, installing new siding or replacing the heating system is also a major investment. With continually rising fuel prices, more and more homeowners are considering how to reduce their energy bills while planning renovations. They want to know where energy savings can be added into their renovation plans prior to making large changes to their home. An energy evaluation can provide this kind of valuable information, along with suitable recommendations for improvements. By Bridget O’Flaherty and Greg Furlong
Who performs an energy evaluation? A Certified Energy Advisor [or CEA] can guide the homeowner by conducting an energy evaluation. Certified by Natural Resources Canada to conduct energy evaluations, a Certified Energy Advisor is trained and experienced in many aspects of the building industry. They look at a house differently than a building inspector or contractor, considering it as a system for providing comfortable, affordable and healthy shelter to its occupants, otherwise known as “home performance”.
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The One Planet Reno in Ottawa, residential winner of the 2014 Canadian Green Building Awards. High insulation levels and air tightness were the starting points of the renovation. Photo: Christian Lalonde [1].
What is an energy evaluation? As thorough as a buyer’s home inspection, a certified energy evaluation provides details of a home’s current energy use and presents options for minor, major and deep retrofits for energy savings in a comprehensive analysis of energy performance. The evaluation includes measurements and calculations of a home’s geometry, detailed data collection on the building construction envelope and energy-using systems, and a blower door test to measure air leakage. All of this information is used to create an energy model of a home using approved software. The results gleaned from this model can then be used to determine heat loads, quantify air leakage and understand indoor air quality. A home’s energy usage is often solely attributed to its furnace. Although the type, efficiency and fuel used by a heating system are important factors, there is much more to a home’s overall performance. Compare this to a car, where
performance is not just about the engine, but about many features working together: aerodynamics, acoustics, glazing, drive train, electrical system and driver behaviour all influence how a car runs. The size and efficiency of the engine plays an important role, but it is only a part of a whole system; a driver’s comfort is affected by a combination all of these parts. A home has similar synergies. First, there is the building envelope, which includes the roof, attics, ceilings, walls, windows, doors, foundations, floors and insulation as well as the home’s natural air change rate [i.e. how quickly the air leaves, taking heat with it]. Then there are the high energy users [as with a car’s engine]: the HVAC systems, water heater, lights and appliances. Finally, an occupant’s behaviour can have a big affect on energy consumption – similar houses often receive very different utility bills!
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A CEA includes the blower door test to measure the air change rate [air leakage], the idea being to find the balance between improving air tightness and reducing heat loss while maintaining good indoor air quality [2 and 3]. Deep retrofits, such as gutting to install new insulation, windows and air barrier are best done by a professional [4].
During the energy evaluation, a home’s data is collected and a depressurization test [also known as a blower door test] is performed, providing not only the information needed to create an energy model, but also serving as a critical diagnostic tool for detecting major and minor air leaks and to assess indoor air quality. A home’s natural air change rate should be in a range that provides good indoor air quality and will determine how much added mechanical ventilation is required. A CEA estimates these air changes and makes recommendations to keep families comfortable and healthy.
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Once an energy evaluation is complete, a CEA identifies what needs attention, where to find the biggest gains in energy conservation, and how to prioritize upgrades among the building envelope and HVAC systems. For example, minor improvements, such as caulking, weather stripping and other airsealing, can often have a big impact on keeping the heat in and can be mostly done by the homeowner themselves. Larger retrofits, such as adding insulation or new windows, and deep retrofits, such as gutting, exterior insulation, re-siding, or adding a new heating system, will most likely require the assistance of a professional. After a home is properly sealed, it is important to determine the right sized HVAC systems to ensure overall comfort. This sizing can be based on the home’s performance as accurately determined by an energy evaluation. Lastly, occupant behavior
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will always influence overall energy use, and a CEA can give homeowners tips on ways to conserve energy and save money. A home is a place to feel safe and comfortable and renovations ensure these feelings last. Upgrading for aesthetic reasons may increase the overall value of a home, but including energy saving measures along the way increases it even more so. The advice received from an energy evaluation increases a home’s ROI [return on investment] and keeps money in a homeowner’s pocket long after a renovation is complete. v Bridget O’Flaherty and Greg Furlong are with the EnviroCentre, a local Ottawa-based environmental non-profit that helps residents, families and businesses save energy and money while reducing their impact on the environment. With a goal of greenhouse gas reduction, EnviroCentre focuses its efforts on improving building or home energy efficiency and sustainable transportation. To learn more, please visit: www.envirocentre.ca
RIGID FOAM PANELS ARE NOT ALL THE SAME Learn where and how they are best used With increasing attention put on thermal bridging in construction, rigid foam is finding its way into more and more homes, but which one should you use?
By Mike Reynolds
There are really three kinds of rigid foam panels you are going to have to choose from - Extruded Polystyrene [XPS], Expanded Polystyrene [EPS] and Polyisocyanurate [polyiso for short]. Before choosing, you should know exactly what you expect it to do, to make sure you walk away with the right one. They are all petroleum-based products but their characteristics, performance and ecological impacts vary significantly.
XPS - Extruded Polystyrene Rated at R5 per inch, but it will off-gas and lose a bit of performance over time. It will act as a vapour retarder [and become even less moisture permeable the thicker it is - 1 inch is about 1 perm, 2 inches about .5 perms]; when taped it can act as an air barrier; it does not absorb moisture, nor is it affected adversely by it. Note: 1 perm and 60 ng are U.S. and Canadian equivalent rates of permeability, below that rate of permeability classifies a material as a type II vapour retarder, suitable for residential construction.
XPS works great in pretty much any circumstance above or below grade, wet or dry. Regrettably, the hydro fluorocarbons [HFCs] most commonly used as blowing agents are far more damaging to the climate than those used with other rigid foam boards. Some manufacturers speak of a coming transition to less harmful blowing agents; that will be great news when it happens. HFCs have a global warming potential [GWP] that is 1,430 times more potent than carbon dioxide. The Kenogami House in Saguenay, Quebec. EPS solid insulation is used below the slab on grade and on the walls over the air/ vapour barrier. the air/vapour barrier is sandwiched between the wood frame and EPS exterior insulation.
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EPS - Expanded Polystyrene Rated at R4 per inch; it’s more permeable to air and moisture than XPS. Two inches of EPS has a moisture permeability rate of between 60 and 75 ng [1 to 1.25 perms], which is on the cusp of qualifying it as a type II vapour retarder, but on the more ‘breathable’ side of the scale. For reference sake, the traditional 6 mil polyethylene vapour barrier has a permeability rating of 3.4 ng, making it about 18 times more vapour resistant than building codes allow. The permeability of EPS can be handy at times if you want to add insulation to an existing wall assembly but are worried about trapping moisture, like retrofitting the exterior of buildings with additional insulation. Though to be absolutely sure you may be better with a mineral wool board which lets moisture pass right through. The lower R value of EPS compared to XPS is in a way compensated for by having a higher R value per dollar, as it is somewhat cheaper. If you’re not worried about losing an inch of space here or there, you’ll get a higher R value with EPS for the same amount of money, albeit with a thicker wall. The performance of EPS may drop slightly when it’s wet [reports I’ve seen indicate somewhere in the area of 10-15 %, so nothing too catastrophic], it will also dry out just as quickly as it got wet and return to its original performance. But there is nothing wrong with putting a little effort into keeping it dry if you can. The GWP of expanded polystyrene blowing agents is about 7 times worse than carbon dioxide, but that’s much less than the XPS.
Polyisocyanurate Rated at R6-6.5 per inch, but don’t count on that. Most insulations actually perform a bit better the colder it gets but polyiso breaks that rule. As of about 15°C its performance starts to deteriorate, and badly. By the time you get down to the -20s °C it’s nowhere near that. It can be a great product to use as long as you keep it warm, which is an odd thing to say about insulation. The news of its R value petering out when you need it most was a bit of shock that hasn’t permeated entirely through the building industry, so you still see it being installed occasionally on the exterior of walls. It won’t offer nearly the thermal protection you think it will in the dead of winter, and it may cause moisture damage due to its lack of permeability. Polyiso comes with a layer of foil on either side to keep the gases in, and at risk of straying off topic, that is worth talking about. Foil is a vapour retarder [or barrier if you prefer], so if you use polyiso on the interior of a stud wall, you won’t need to add an additional vapour retarder.
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And since there is foil on either side of the panel, you end up with a harmless second vapour retarder, but one that can help in summer months when there is a risk of the vapour drive reversing due to air conditioning during hot humid weather. Any inward-bound moisture would be stopped at that inner layer of foil, which will be warmer than the foil on the other side, so you reduce your risk of summertime condensation. That foil is the reason it can be problematic on the exterior, as you would be adding an exterior vapour barrier where you likely don’t want one. On the good news side, the GWP of blowing agents in Polyiso is similar to those in EPS, and in the right circumstances its R value is significantly higher, which deservedly or not helped earn it the reputation of being the ‘greenest’ foam. It can be a great choice when kept above freezing and away from moisture - so above grade for sure, and it makes a great interior thermal break when it’s kept a bit warmer by batt insulation in stud cavities. Being petroleum based should not result in foam being condemned by green builders on principle alone; it should be looked at in perspective. There are other great types of insulated sheathing [mineral wool and fiberglass to name two] and each will have their own benefits, drawbacks, carbon footprint and embodied energy through manufacturing, so even the greenest of the green will have some measurable impact. It takes energy to save energy, and manufacturing insulation is arguably one of the more noble things we currently do with fossil fuels. In conclusion: polyiso gets top marks for being ‘eco’ if you can handle its moody disposition. EPS is versatile and in the middle ground for performance, financial and ecological cost, and XPS is a top performer but comes with some unfortunate baggage. As soon as XPS completes its transition to less harmful blowing agents, I’m sure it will be welcomed into the green building community. v Mike Reynolds is a former home builder, a LEED for Homes Green Rater and the editor of Ecohome.net, the affiliate web site of ecoHouse Canada.
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