Pushing the Envelope Canada

< Previous20 Spring 2023 • Ontario Building Envelope Council adhesives may have been adversely affected by long-term exposure to temperatures below zero degrees Celsius prior to heating. All ad- hesive materials are required to be stored in a heated room or in smaller heated construction boxes on the roof near the area of work. Ad- hesive should have been transferred directly from the containers in a heated area directly on to the smaller heated construction boxes, which should have been rotated frequently to ensure adhesive in use is within correct appli- cation temperature parameters. Overall, sev- eral deﬁciencies were observed and reported as part of the general conformance reviews, revealing a general lack of quality control by the contractor. LESSONS LEARNED Design and construction of roof assemblies for buildings built in Canada are no longer a simple composition of multiple layers of roof components, relying on the proprietary de- sign of the system by the manufacturer. Low- sloped roof assemblies, excluding protected roof membrane assemblies, are required by the Ontario Building Code, introduced by the NBCC 2015, to resist the site-speciﬁc wind uplift values based on the geographical loca- tion and surrounding terrain, exposure of the building, openings in the building, height of the building, size of the roof area, and height of the parapet, all along the ﬁeld, perimeters, and corners of the roof. To achieve this, the ﬁrst step is for the de- signers to calculate and/or use the available online calculator to determine the site-specif- ic wind uplift values and include them in the speciﬁcations. It is important to retain a pro- fessional experienced in these calculations to verify the output from the online tool or perform necessary calculations, as the online tool has limitations. It is also recommended that the designer includes requirements in the speciﬁcation to provide submittals con- ﬁrming that the proposed roof assemblies are rated to resist site-speciﬁc wind uplift values, and that corresponding test reports are issued by third-party testing laborator- ies. To limit uncertainties in achieving com- pliances, the designer may speciﬁcally note that extrapolation methods of compliance and the use of non-calibrated testing facili- ties per SIGDERS voluntary standard are unacceptable. The manufacturers are required to pro- vide a suitable roof assembly that meets the site-speciﬁc wind uplift resistance re- quirements at all zones of each of the roof areas in the building. It is imperative that the designer obtains the test reports sup- plied by a third-party testing facility with the equipment calibrated per SIGDERS, as a project submittal, and review the rating of the system being proposed to verify if they meet the site-speciﬁc wind uplift resistance requirements for each of the roof areas at all zones. It is also important to understand if the manufacturer is proposing to meet the requirement using the ANSI/SPRI WD-1 extrapolation method, and if so, inquire the suitability of the extrapolation method tak- ing into consideration the assembly mode of failure. The safest approach is to avoid using the extrapolation method and to ensure that the rating of the proposed roof system is con- ﬁrmed through testing and meets or exceeds site speciﬁc wind uplift resistance values for all roof zones. Good workmanship matching the test- ed assembly and following the manufactur- er’s instructions is critical, including the use of proper spacing, pattern and installation timing for each of the components. Storage of materials and precautions to be taken at the time of installation for the effective func- tioning of the components are important. For those components that are affected by cold weather conditions, a winter grade product as offered by the manufacturer is best to be used. Additionally, attention to details at the time of construction, such as temporary seals at perimeter scuppers and openings, and along end of workday assembly terminations, is important to avoid loss of integrity of the roof assembly due to extreme weather con- ditions. Quality control measures by the gen- eral contractor and rooﬁng trades ensuring proper installation of materials and compon- ents are essential. A general conformance FEATURE n n n Roof assembly being tested in the SIGDERS calibrated ISO/IEC 17025 certiﬁed lab at EXP’s Drummondville facility for a manufacturer.Pushing the Envelope Canada 21 n n n FEATURE review by the designer and a qualiﬁed con- sultant as required is imperative. Likewise, if wind uplift damage occurs causing delamin- ation of the roof assembly, it is prudent to involve a qualiﬁed professional to provide recommendations for the implementation of temporary restraints on the roof system to avoid any potential further damage and ad- verse site safety issues. With the changing climate and future pre- dicted adverse weather conditions, construc- tion of roof assemblies resisting the site-specif- ic wind uplift values as discussed above is a starting point to achieve long-term durability of roof assemblies. Further enhancements to the roof assembly for climate change resiliency are currently addressed by a volun- tary standard, CSA A123.26 - Performance re- quirements for climate resilience of low slope membrane rooﬁng systems. Designers must be aware of their role and responsibilities regarding proper roof system design in any given roof as- sembly. It is also critical that contractors store and install all roof system materi- als in accordance with best practices and manufacturers requirements. Finally, it is recommended that manufacturers utilize industry recognized laboratory calibration and that extrapolation methodology be used cautiously with a focus on the system mode of failure to determine if it is appro- priate for use. It is crucial that designers are aware of the pitfalls presented above, when properly designing a roof system’s wind uplift resistance performance. Many failures are the result of a series of com- pounded errors or misjudgments, which in combination may result in the “perfect storm” if they are not pre-emptively rec- ognized and addressed during the design and construction processes. n Sathya Ramachandran, Architect OAA, AAA, NSAA, AAPEI, B.Arch., M.A.Sc., is a registered Architect with advanced educa- tion in building science and over 21 years of experience in research and consulting for projects built across North America. He is the Director of Building Science practice in the Greater Toronto area and Hamilton at EXP Services Inc. Mark Summerﬁeld is the Head of Roof Con- sulting within the building science practice in the Greater Toronto and Hamilton area at EXP Ser- vices Inc. With over 30 years of experience across Canada, Mark has deep knowledge in various rooﬁng systems and experience in several types of roof and building envelope assemblies. Anthony F. Perri, B.Arch.Sc., LEED® AP is a Project Manager with the Building Science practice in the Greater Toronto and Hamilton area at EXP Services Inc. With over 14 years of experience, Anthony is an all-rounder in assess- ing existing roof assemblies, preparing design documents and speciﬁcations for roof replace- ments, and conducting construction reviews. With the changing climate and future predicted adverse weather conditions, construction of roof assemblies resisting the site-specific wind uplift values as discussed is just a started point to achieve long-term durability of roof assemblies. 22 Spring 2023 • Ontario Building Envelope Council BUILDING ENVELOPE SYSTEMS EXAM DATE Friday, May 12, 2023 TIME 1:00 P.M. – 4:00 P.M. EST LOCATIONS •BSSB Ofﬁce, 2800 14th Avenue., Suite 210, Markham, ON L3R 0E4 (1:00 pm – 4:00 pm ET). •Kitchener-Waterloo area – TBD. •Ottawa area – TBD. •Entuitive, 10055 106 Street NW, Suite 650, Edmonton, AB – (9:00 am – 12:00 pm MT). MATERIALS EXAM & MECHANICAL SYSTEMS EXAM DATE Friday, October 3, 2023 TIME 1:00 P.M. – 5:00 P.M. EST LOCATIONS •BSSB Ofﬁce, 2800 14th Avenue., Suite 210, Markham, ON (1:00 pm – 5:00 pm ET). •Kitchener-Waterloo area – TBD. •Ottawa area – TBD. •Entuitive, 10055 106 Street NW, Suite 650, Edmonton, AB – (9:00 am – 1:00 pm MT). UPCOMING BUILDING SCIENCE SPECIALIST EXAM DATESPushing the Envelope Canada 23 I t is generally expected that buildings are designed and constructed to last and ex- ceed their useful service life. The build- ing envelope is the primary level of defense against the external environmental condi- tions that directly impact the health and per- formance of the building. When the building envelope becomes compromised, the under- lying building structure is also vulnerable to degradation. Simultaneously, the occupants of the building, as well as the public, are at risk from a health and safety perspective. If these problems are not addressed in a timely manner or ignored, the risk of catastrophic failure increases signiﬁcantly. This article will provide an overview of recent building envel- ope failures and how this has impacted vari- ous jurisdictions on how they currently assess and rectify building problems. When it comes to incidents over the past number of decades, there have been a series of devastating building envelope failures that have occurred within Ontario and other juris- dictions (see Table 1, below). The failures are Mitigating Building Failures: Why Mandatory Building Envelope Assessments are Required in Ontario Loose concrete knocked off from an exposed slab during a building envelope assessment. Photos courtesy of Daniel Aleksov. innumerable to list, but the most prominent failures have been referenced that depict the severity of corresponding outcomes. The ﬁrst question that pops into our mind is why would something like this happen? There are a plethora of contributing factors that may have led to the failure such as a problem with de- sign, workmanship, materials, environmental conditions, damage, inadequate maintenance, assessment, and repairs. The condition of the building envelope will vary based on which time stamp is selected during its useful service life. In many cases, the appropriate steps to resolve the building envelope problems are taken far too late when the damage has al- ready been initiated. This makes mandatory building envelope assessments a necessary op- tion to mitigate future building failures. A building envelope assessment is a comprehensive review of the roofs, walls, By Daniel Aleksov, P.Eng., BSS, Leading Edge Building Engineers n n n FEATURE Building Name/TypeDateLocationType of Failure and Consequence Highrise ResidentialMay 1979New York, NY Terracotta failure from 8th ﬂoor struck and killed 1 person. This led to Local Law 10. Highrise BuildingDecember 1999New York, NY Section of brick collapsed onto a street prompting changes to Local Law 10 and Introduction to Local Law 11. First Canadian Place Highrise Commercial May 2007Toronto, ONFractured marble stone piece detached and fell below. No casualties. Highrise ResidentialNovember 2008Montreal, QCPartial parking garage collapse killing 1 person. Marriott Hotel HighriseJuly 2009Montreal, QC Concrete detached from façade and fell from 17th ﬂoor. Killed 1 person and injured another. Three Story CommercialApril 2010Toronto, ON Section of brick collapsed above a restaurant onto Yonge Street sidewalk. No casualties. Algo Shopping MallJune 2012Elliot Lake, ONGarage deck/roof collapse into shopping mall. 2 dead and over 20 injured. Highrise ResidentialApril 2015Toronto, ONSection of brick collapses from a TCHC building. No casualties. Highrise Residential December 2019New York, NYTerracotta piece detached from façade and killed a pedestrian. Highrise ResidentialJune 2021Surfside, FLPartial collapse of a 12-storey building killing 98 people and over 10 injured. Table 1. List of Building Failures.24 Spring 2023 • Ontario Building Envelope Council windows, doors, and foundations of the building. The assessment is designed to iden- tify potential deﬁciencies with the building envelope that could compromise its perform- ance, such as leaks, cracks, loose compon- ents, and deterioration. An assessment typ- ically includes ﬁrst and foremost a close-up visual review along with water testing, acous- tical sounding, thermographic scanning, and destructive testing to the exterior and/or in- terior assemblies if required. One of the most prevalent issues that are commonly reported at all types of buildings is water penetration to the interior space. Water penetration has Loose concrete knocked off from an exposed slab during a building envelope assessment. the potential to cause several different prob- lems from damages to interior ﬁnishes, which can lead to mould and initiation of a ﬁre if in contact with an electrical source. Long exposure to water along with other elements without effective protection (i.e. water barrier) and a drainage system increas- es the risk of rot and corrosion of cladding at- tachments and structural components. Dur- ing the course of our engineering work, we have encountered on multiple occasions at various buildings isolated areas of delamin- ated (loose) concrete that were on the verge of spalling (detaching) from exposed slabs, walls, and guards. Even a small piece of con- crete detaching from a high-rise building has the potential to injure or kill a bystander on the ground, which occurred from the 17th storey of a hotel in Montreal, Quebec, back in 2009. Similar incidents of localized failure of falling Terracotta resulted in two separate deaths occurred in New York City in 1979 as well as 2019 (see Table 1, 23). The exterior wythe of masonry brick walls requires a combination of both vertical and lateral supports to maintain their structural integrity. The lateral supports in some cases can be insufﬁcient and/or severely corroded to the point where the wall is not properly re- strained and can shift when there is enough horizontal stress applied from weather events such as freeze-thaw thermal cycles as well as wind pressure. We were requested to perform a review of a section of brick that had shifted approximately 25-50mm at the top of the wall of a six-storey building. A retroﬁt solu- tion was recommended to contain the wall during the winter until a permanent repair could be completed in the spring. In Toronto, there have been at least two recent incidents of sections of masonry brick walls collapsing at both a 12-storey high-rise building as well as a three-storey commercial building (again, Pushing the Envelope Canada 25 see Table 1, 23). Fortunately, these building envelope failures did not result in any injuries or fatalities. Despite the past incidents listed and the importance of building envelope assess- ments, they are not currently mandatory in Ontario. Building owners are not required to conduct assessments, and there are no regulations in place to ensure that assess- ments are conducted on a regular basis to help owners be aware of the condition of their buildings. Mandatory building envelope assessments would help to mitigate building failures in Ontario by ensuring that buildings are reviewed regularly for potential deﬁcien- cies and hazards. Building owners would be required to conduct assessments at regular intervals, at least every ﬁve years, and to address any issues identiﬁed during the as- sessment. This would help to prevent small issues to escalate into severe problems that could compromise the safety of the build- ing. Other jurisdictions like New York City have implemented mandatory façade assess- ments back in 1980 following their Terracotta failure. New York City has the oldest and most robust assessment program that is run statewide. In Canada, Quebec was the ﬁrst province to implement a mandatory building envelope assessment program following the incident in Montreal in 2009. Bill 122 was passed approximately 10 years ago as a direct response. The ﬁrst major building envelope/struc- tural failure experienced in Ontario was the collapse of the roof structure at the Algo Shopping Mall in Elliot Lake in 2012. The fail- ure resulted in two deaths and over 20 injured. The ofﬁcial court judgement from this case included recommendations to have minimum structural maintenance standards and per- iodic inspections. The report highlighted the fact that these minimum maintenance stan- dards exist in Quebec. The implementation of mandatory building envelope assessments would require a signiﬁcant shift in the way that building safety is regulated in Ontario. The Ontario Building Code (OBC) current- ly sets out minimum standards for building construction and maintenance, but it does not require regular assessments of existing buildings. To implement mandatory building envelope assessments, the OBC would need to be amended to include requirements for regular assessments of building envelopes and enforcement by the authorities having juris- diction. Industry associations like the Build- ing and Concrete Restoration Association of Ontario (B&CRAO) have been advocating for these assessments for many years follow- ing the Algo Mall roof collapse and the pro- cess has been slow and met with resistance. The Ontario Building Envelope Council fully supports this initiative and hopes that it will be ratiﬁed in the very near future. Building failures pose a signiﬁcant risk to public safety in Ontario. Mandatory building envelope assessments can help to mitigate these risks by ensuring that buildings are well-maintained and safe. Although there are challenges to implementing mandatory assessments, the beneﬁts of such assessments far outweigh the costs. By protecting the safe- ty of occupants, improving energy efﬁciency, protecting property values, and supporting the economy, mandatory building envelope assessments can help to ensure that Ontario’s buildings are built to last.n Daniel Aleksov, P.Eng., BSS is a princi- pal and co-founder at Leading Edge Building Engineers. He also currently serves as the vice president of the Ontario Building Envelope Council. Shifted top section of a masonry brick wall inadequately supported laterally.26 Spring 2023 • Ontario Building Envelope Council T he border between a building’s cli- mate-controlled interior and the outside is known as the building envelope, sometimes known as the building shell, fabric, or enclosure. How much energy is needed for heating and cooling depends heavily on how energy-efﬁcient building en- velope components – such as external walls, ﬂoors, roofs, ceilings, windows, and doors – perform. It is important to consider how the build- ing envelope affects energy use because, globally, space heating and cooling account for about one-third of all energy used in buildings. In cold climates, this number can reach 50 per cent. Employingroof consulting Ontarioservices can help you design an energy-efﬁcient rooﬁng system. CREATING ENERGY-EFFICIENT BUILDING ENVELOPES The amount of incoming and exiting heat ﬂow has a signiﬁcant role in inﬂuencing the comfort level and cost of running energy-efﬁ- cient buildings. A region of high temperature will naturally transfer heat to a region of low- er temperature. The heat ﬂow through an assembly in- crease with temperature differential. In the Energy Efﬁcient Building Envelopes: Renewable Envelope Best Practices winter, a heated structure will lose heat to its chilly exterior. Additionally, an air-con- ditioned building will absorb solar heat from its extremely warm exterior during the summer. Energy performance is all about ﬁnding a balance. ENERGY EFFICIENCY OF A BUILDING The energy efﬁciency between the interi- or and exterior of the walls and roof, and the composition of the insulating materials both affect how quickly heat transfer happens through these systems. Glass, concrete, and all metals are examples of materials that are excellent conductors of heat. Other substanc- es with a high resistance to heat transfer are referred to as insulators, including ﬁberglass, mineral wool, and foam sheathing. Heat energy can enter and leave a struc- ture in three different ways: conduction, con- vection, and radiation. These kinds of heat transmission all take place simultaneously in a building and are crucial to maintaining the building’s thermal equilibrium. BREAKING THE THERMAL BRIDGING It’s important to avoid thermal bridging while constructing energy-efﬁcient building envelopes. Thermal resistance, thermal con- ductance, and thermal conductivity can all be used to rate the performance of an insulating material or the effectiveness of energy-efﬁ- cient building envelopes. This is referred to as the “R-value.” When structural components transport so- lar heating and other thermal energy through the insulation, thermal bridging happens. The R-value of your insulation may decrease by 50 per cent as a result of thermal bridging. To prevent thermal bridging as much as possible, make sure there is a continuous re- gion of stiff insulation on the cold side of the FEATURE n n n This article is reprinted with permission from Accent Building Sciences. It was fea- tured originally on their blog on February 14, 2023. To read more like this online, visit https://absi.ca/blog/.Pushing the Envelope Canada 27 wall assembly and that the insulation isn’t be- ing considerably compressed. The resistance to heat ﬂow of insulators and building enve- lopes is what makes them effective. ENSURE AIR TIGHTNESS In addition to allowing heat to escape and cold to enter, leaky windows, walls, ducts, doors, louvres, and roofs can also cause con- densation to collect in the building envelope, which can result in the formation of mold and premature deterioration of the building material. In order to keep the interior at a comfortable temperature, an adequate air barrier is required to aid in preventing air leakage. Implementing heat recovery ventilation solutions can also protect building occupants’ health while recovering 50 per cent or more of the energy from exhausted air. The ven- tilation system of the building should be the only source of fresh outside air. PASSIVE COOLING WITH PHASE CHANGE MATERIALS Phase change materials (PCM) are building materials that can collect heat gains during the day through their melting process and release the heat at night when solidify- ing. They do this by utilizing free cooling through natural ventilation and have tremen- dous potential to passively minimize energy consumption caused by heating or cooling systems. Implementing PCM layers when design- ing a building envelope can help reduce ener- gy consumption by recycling thermal energy. PCM products come in many forms and can be used in various ways when being imple- mented into a larger building system. BE AWARE OF NEW ENERGY- EFFICIENT TECHNOLOGIES It is always important to make good use of new technologies. New ways to conserve thermal energy are being implemented constantly. A good example is the devel- opment of large-area ﬂuidic windows that save enough energy to offset the carbon and heat energy consumed during their production. Implementing new solutions as they are developed is a great way to take advantage of technological progress and reduce total ener- gy consumption. Oftentimes, energy savings can be greatly increased over the lifetime of a building.n n n n FEATURE28 Spring 2023 • Ontario Building Envelope Council T he search for cleaner, greener energy is giving rise to rooftop solar panels on all property types. And while there are clear advantages to harvesting renewable energy from the sun, im- portant design and installation considerations must be made to en- sure those beneﬁts shine. The ﬁrst consideration concerns the type of solar panel technology used to convert sunlight into energy. Today, there are two primary methods: •Photovoltaics(V), solar panel technology that generates power by using materials that absorb light and produce electrons (aka the photovoltaic effect), such as silicon and arsenide. •Concentrated solar power(CSP), which are panels comprised of mirrors and tracking systems that concentrate sunlight onto a small heat collector. PVs are the most common type of solar panels found on top of modern buildings. They are typically supported by a mechanical- ly fastened racking system or ballast restrained system. The former is attached to the roof by penetrating the rooﬁng membrane, while ballast restrained systems use ballast weights to hold the assembly in place without the need for roof penetrations. As such, mechan- ically fastened racking systems can be installed on pitched or ﬂat roofs, while ballast restrained systems are mostly for ﬂat surfaces. INVESTING IN ABUNDANT ENERGY The addition of any PV solar panel system will increase a roof’s superimposed dead load (SDL), thereby requiring design elements to accommodate their weight. This can add costs to any new build or renovation, but it’s important to remember the long-term savings that will result from using solar power. As RJC Engineers’Design Guide for Rooftop Solar1explains: “In new construction projects, the designer should always consider alerting the owner and design team to the long-term savings that potentially result from designing new roofs for future a PV installation, considering the anticipated rise in the use of solar energy in the future.” Undoubtedly, adding rooftop solar panels to any building – new or old – comes with design and cost discussions. Addressing these factors early into the design process, and ensuring the beneﬁts of solar energy generation are well understood by all stakeholders, helps teams em- brace clean energy solutions. After all, adds RJC’s guide: “Although solar panels have signif- icant cost savings throughout the life of the building, upgrading ex- isting buildings for solar panels can prove to be a costly undertaking … considering how to make buildings solar ready early in the design process of new building projects can save building owners and opera- tors signiﬁcant future upgrading costs.” SOLAR PANEL CASE STUDIES RJC is eager to continue sparking Canada’s rooftop solar panel industry. In recent years, it has helped clients across Canada arrive at solar panel racking solutions which meet their speciﬁc building objectives. One success story is in full view at the CF Chinook Centre, where RJC worked with CF, ENMAX, Mulvey + Banani, and Resco Energy to install 1900 solar panels in an 800 kW system innovative pilot proj- ect. The goal was to test two-way power ﬂow on ENMAX Power’s secondary network, a part of the grid that exists in high-density areas and currently only allows one-way power ﬂow due to its highly reliable design. Another demonstration of rooftop solar power took shape atThe Edge2in Edmonton, Alberta. This is a 10-storey ofﬁce building development brought to life by Dub Architects and features a south wall with 560 solar panels that provide 80 per cent of the building›s electrical load and represents one of the largest of its kind in Canada. Here again, RJC was proud to help Dub Architects see its vision through by providing structural engineering and structural glass engineering services for this landmark project. It’s been years since rooftop solar panelling began in Canada. Thanks to its experience helping clients take advantage of this renewable en- ergy source, RJC looks forward to facilitating clean energy solutions for years to come.n Here Comes the Sun: Considerations for Rooftop Solar Panelling REFERENCES: 1.Jeff Rabinovitch, M.Sc., P.Eng., LEED® AP BD+C. Design Guide for Rooftop Solar. RJC Engineers. https://www.rjc.ca/ rjc-media/research/design-guide-for-rooftop-solar.html. 2.RJC Engineers. “The Edge by Dub Architects.” Architectur- al Record Magazine. https://www.rjc.ca/rjc-media/published/ the-edge-by-dub-architects.html. This article is reprinted with permission from RJC Engineers. It was featured originally on their blog on September 30, 2022. To read more like this online, visit https://www.rjc.ca/rjc-media/blog/. FEATURE n n nSince1987 the Ontario Building Envelope Council (OBEC) has been bridging the gaps amongst the architectural, engineering, research, manufacturers, and construction communities. Their non-profit organization addresses today’s challenges facing building performance and sustainability. One of OBEC’s keys to success is their dedication to building science education at all levels. Guided by the Board of Directors, OBEC is focused on delivering: • Information forums for the exchange of ideas and information on building science • Access to current technical information and best practices • Educational programs for the benefit of the building community • Guidance on current trends and issues to the research and development community • Recommendations regarding improvements to codes and standards Educational opportunities exist through conferences, technical forums, field trips, and monthly dinner presentations. This information is made available to members of OBEC. Members can be individuals, corporations, students, or members marked as Professional for holding a BSS designation. Corporate Membership - A Corporate Member may be named as such if the member is a corporation, an individual to act as its representative at any meeting of members of the Corporation must be named as the Corporation’s main representative. A Corporate Member is entitled to five (5) named persons to be listed in the membership database to receive all society notifications as well a copy of “Pushing The Envelope Canada” magazine. All company employees are eligible to receive the member rate for events. Individual Membership - An Individual Member may be designated as such if the member is an individual person. Join OBEC and join hundreds of other like-minded people in your industry. Submit your membership application today and open the door to so much more. 2800-14th Ave., Suite 210 Markham, ON L3R 0E4 Tel: 647-317-5754 Fax: 416-491-1670 Email: info@obec.on.ca obec.on.ca MEMBERSHIP YEAR: JUNE 1 ST - MAY 31 STNext >