< PreviousPushing the Envelope Canada 13 Message from the President Daniel Aleksov Principal & Co-Founder Leading Edge Building Engineers A s we approach the fall of 2024, it is important to reflect on the amazing year that has passed for our members of the Ontario Building Envelope Council (OBEC). I am grateful to be the president in a time where many new initiatives are unfolding thanks to the countless efforts of our board and committee members, au- thors, speakers, sponsors, and members at large. It is also important to thank our past board members and volunteers who have helped elevate OBEC to where it is now. This association has been built by individuals who have the passion and dedication to pass on expert knowledge of building science and leave a legacy behind to the next generation of professionals in the industry. Our continued efforts to partner with like minded organizations is helping spread awareness of our association while simultaneously providing more education, social, and business opportunities to our members. First, our inaugural golf tournament with the Canadian Condominium Institute (CCI) Golden Horseshoe chapter was a tremendous success and we appreciate everyone who participated and sponsored this event. The overwhelming positive feedback is encouraging to make this a regular summer social event moving forward. In terms of upcoming continuing education, the joint OBEC/ IIBEC BES Conference is fast approaching and packed with high cali- bre presentations and speakers from across North America. You will also have access to a vast number of industry exhibitors that can help you understand the latest trends and technologies available at your disposal in the building envelope market. Do not miss the opportunity to benefit from this event as well as participate in the OBEC annual general meeting (AGM) which will be held on the second day on October 1, 2024. Your continuous feedback and suggestions from ongoing surveys and polls have helped us with planning and executing on events and initiatives that are aligned with OBEC’s strategic short-term goals. We would like to reassure our members that their input is always valued and taken into consideration as we plan for every upcoming year. Please continue to share your unique perspectives and insights as OBEC approaches four decades as an association. We are thrilled that post-secondary students continue to become OBEC members and host their own student chapter events as well as attend OBEC organized events. Many thanks to our corporate spon- sors that have facilitated and supported this initiative for the past few years. This year the Anthony A. Woods (The Beckie) award will be granted to recognize an individual, nominated by their peers, who has made a significant contribution to the design, construction and per- formance of the building envelope. The winner of the award will be announced at the upcoming AGM. In closing, I am incredibly enthusiastic and optimistic about the future direction of OBEC and the major initiatives that we are collect- ively working on. There is a lot of hard work and challenges to over- come, but we are determined to reach our lofty goals. Thank you for your continued support, dedication, and commitment to excellence. I look forward to working closely with each of you as we navigate this exciting journey together. If you are interested in volunteering on one of our many active committees, please reach out to us via email at info@obec.on.ca. n President: Daniel Aleksov, P.Eng., BSS, Leading Edge Building Engineers Inc. Vice-President: Negar Pakzadian, B.Eng., M.Arch., MBSC., BSS, CPHD, Major Capital Project Manager Treasurer: Matthew Gelowitz, M.A.Sc., CPHC, LEED® AP, Synergy Partners Consulting Ltd. Operations Manager: Sherry Denesha, Ontario Building Envelope Council (OBEC) Directors: Mohammed Dawoud, P.Eng, M.Eng, BSS, CPHD, NFRC Certified Simulator, Ennova Facades Brandon Gemme, P.Eng., BSS, CPHD, Leading Edge Building Engineers Inc. Andrea Mucciarone, BA, MBSc., BSS, RJC Engineers Antoine Possik, Northern Caulking Inc. Robert Quattrociocchi, BSS, Synergy Partners Shohreh Salimpour, M.Eng., P.Eng., M.Arch., OAA (Int.), LEED® AP, PMP, OHE Consultants Kelsey Saunders, KPMB Architects BOARD OF DIRECTORS The Future Direction of OBEC n n n UP FRONTPushing the Envelope Canada 15 n n n UP FRONT O BEC is currently working with the other BECs across Canada to offer the Building Science Specialist (BSS) designation. The BSSB will promote the Building Science Specialist designation across the country, leading to greater prestige for holders of the BSSO, and giving the designation increased authority. As part of this process, we’re doing away with the Professional Member category; you will become an individual member holding the Building Science Specialist designation. UPCOMING BUILDING SCIENCE SPECIALIST EXAMS AND EVENTS BES+ 2024 IIBEC/OBEC BES DATE September 29 to October 1, 2024 LOCATION Toronto, Ontario MATERIALS EXAM & MECHANICAL SYSTEMS EXAM DATE Friday, October 18, 2024 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 (1:00 pm – 5:00 pm ET). •Ottawa area – TBD (1:00 pm – 5:00 pm ET). •Edmonton, AB – TBD (9:00 am – 1:00 pm MT). REGISTER TODAY HERE: HTTPS://BSSB.CA/BSS-EXAM/BSS-EXAM-APPLICATION-2.16 Fall 2024 • Ontario Building Envelope Council FEATURE n n n To Retain or Not to Retain: Snow on Your Metal Roof? By Rob Haddock, S-5! & Nathan Morlock, Engineered Architecturals Ltd. T he debate surrounding snow re- tention is a prevalent topic among Canadian designers and contractors. One perspective cautions against retaining snow on roofs due to concerns over com- promising the building’s structural integrity. There is also apprehension that accumulat- ed snow could exceed the roof’s design load capacity, potentially leading to failure. The other perspective advocates for mechanical snow retention to manage snow evacuation in a controlled manner to prevent hazard- ous rooftop avalanches and minimize safety risks to pedestrians and property. What is the “safe” middle ground? Understanding the implications of each perspective is crucial not only to ensure the safety and longevity of the roof but also for overall public safety. The Canadian National Building Code (NBC) supports using snow retention only when necessary and encourages planning for natural snow shedding to avoid exces- sive accumulation.1 However, the terms “if required” and “natural shedding” are vague. Does “natural shedding” become a safety issue when a rooftop avalanche crushes a vehicle, or only after fatalities occur? Addi- tionally, what happens if ice dams form on eave overhangs, blocking “natural” snow shedding? The Roofing Contractor’s Association of British Columbia (RCABC) defines high snow load areas as those with snow loads over 3.5 kPa (73.10 psf) and recommends design- ing roofs with a significant slope to facilitate snow shedding. 2 Congruent with NBC, the use of snow retention systems is advised only where public hazards exist, e.g., pedestrian areas or building entrances. 2 What about utility workers checking a meter or children having a snowball fight in the backyard? “Natural” snow shedding. “Natural” snow shedding. Photos courtesy of S-5!Pushing the Envelope Canada 17 n n n FEATURE The RCABC also states that allowing snow to discharge freely from roofs is preferable to avoid roof system damage, 2 though more damage is often seen from “free discharge” than retention. Canada has not seen significant structural failures from snow accumulation on build- ings built to code.3 The NBC states that light frame buildings, as defined in Part 9, have not collapsed under these loads. Part 9 covers basic home and small building requirements, while Part 4 covers more complex structures with stringent safety standards.3 The NBC 2020 emphasizes that structural design re- quirements are defined by local legislation.3 Modern Canadian buildings are designed to withstand loads based on climatic criteria from the federal department, Environment Canada, which are based on 1-in-50-year event data.4 For small light frame buildings, Part 9 uses simplified calculations involving snow load (S s ), reduction factor (C b ), and rain surcharge (S r ). More complex buildings follow Part 4, considering factors like build- ing type, adjacent structures and snow drift.4 In high snow load or remote areas with- out local climate data, municipalities con- tract with Environment Canada for specific climatic data for a small fee. A registered professional ensures the design meets build- ing codes and withstands anticipated loads. 4 Whether Part 4 or Part 9, the trick is to get the design vertical roof snow load credibly correct – a difficult proposition considering the objective language of code. Then, given the irregular patterns of extreme weather events globally, prudence is required to re- duce future risks in light of code or climate changes. If higher minimum safety factors were mandated by codes, it would ease the burden on designers. Typical verbiage on term sheets from snow retention suppliers may read: “Our de- sign and quote are based on the ‘known’ snow load. It’s the customer’s obligation to monitor the rooftop snow load and remove or reduce excessive snow loads to avoid system failure. We recommend a licensed engineer review the layout as designed to avoid potential system failure.” (So, the buck is passed again.) But practically speaking, how will the “customer” monitor actual snow loads, and is it a safe practice to reduce excessive snow loads during or following a blizzard? Every year there are reports of rooftop avalanches causing extensive property dam- age and personal injury. Often this is due to attempts to remove snow from a roof. Rec- ommending an engineer review the layout to avoid system failure does not eliminate the hazard – it just shifts blame to the engineer. The metal roof experts at S-5! emphasize the primary function of snow guards is to prevent snow from sliding off the roof in an uncontrolled manner. A rooftop avalanche endangers people and property whether an- ticipated – or not. A properly designed snow retention system will allow snow to manage- ably evacuate (by thaw and sublimation). It’s the uncontrolled and unexpected rooftop avalanche that causes damage and life/safety issues. A common misconception is that snow guards can lead to an “excess” accumulation of snow, exceeding the design load capacity prescribed by the building code. For this to happen, an event would need to surpass the 1-in-50-year data including the designer’s safety factor. The NBC and its Structural Commen- taries include provisions for reducing roof snow loads based on factors such as roof slope and slipperiness. However, the code also provides cautionary guidance regarding these reductions, stressing the importance of carefully evaluating actual conditions and as- sociated risks. For instance, if the structure was initial- ly designed to shed snow and reductions in snow loads (according to incumbent code) were implemented and subsequently a snow guard system was added, the scenario could increase the risk of structural failure earlier than the failure of the snow retention system. More frequent failures stem from under-designed snow guard systems that fail to account for three basic design factors adequately. While engaging a professional engineer to assess site-specific climatic data according to code is essential, it is also crucial to recognize the three variables frequently ig- nored: design roof snow load, roof angle and roof (rafter) length. Having conducted 5,000 plus load tests on every conceivable metal roof profile, S-5! recommends the installation of a certifiably tested snow retention system and engineered to these three site-specific variables using an appropriate factor of safety. (The S-5! system calculator defaults to 2.0 but enables the user to modify.) S-5! ColorGard allows snow to manageably evacuate by thaw and sublimation. 18 Fall 2024 • Ontario Building Envelope Council FEATURE n n n UNDERSTANDING THE PRECISE MATH AND SCIENCE Properly calculating the required popu- lation and spacing of snow guards is critical for any project. If it is inadequate, the system will fail at below-design snow loads – if over- ly adequate, there is a risk of overspending. Appropriate design is determined by science and math, not guesswork. The correct population is found by calcu- lating the tributary service loads to be resisted and matching them to the tested, allowable load resistance of the specific snow retention system proposed for the project. DETERMINE THE VECTOR FORCE The force applied to a snow guard system is a simple calculation but varies widely with: •The design roof snow load; •Roof slope; and •(Rafter) length from eave to ridge. Further, the buyer should demand evidence of three quality assurances for a reliable system design from the snow guard vendor: 1.Certified testing specific to the roof being used on the project; 2.Certified manufacturing; and 3.Proof of engineered calculations. KEY TAKEAWAY S-5! advocates for a rigorous approach to snow retention system design, emphasizing the importance of a certifiably tested and engi- neered snow retention system based on precise load calculations. Their snow calculator tool as- sists designers and engineers in determining the optimal configuration of snow guards for your metal roof project. For more information, visit www.s-5.com. n Rob Haddock, director of the Metal Roof Advisory Group and CEO and founder of S-5!, is a former contractor, award-winning roof forensics expert, author, lecturer and building envelope scientist who has worked in various aspects of metal roofing for five decades. Nathan Morlock, founder of Engineered Architecturals Ltd., and the inventor of the Turtle Rib brand with five patents pending brings a unique background as a union- trained sheet metal worker. Morlock later became a partner in a specialty architec- tural products company. He has garnered international expertise evaluating building product manufacturers and offers extensive- ly tested technical products with a focus on supporting installations to ensure project success. Engineered Architecturals proudly offers S-5! REFERENCES: 1.Canadian National Building Code (NBC), Structural Commentaries (User’s Guide – NBC 2015), Com- mentary G. https://nrc.canada.ca/en/ certifications-evaluations-standards/ codes-canada/codes-canada-publica- tions/structural-commentaries-users- guide-nbc-2015-part-4-division-b. 2.Roofing Contractor’s Association of British Columbia (RCABC), Roof Practices Manual (RPM), Section 1.1.3.2 Snow Loads. https://www. rcabc.org/technical/roofing-practi- ces-manual-rpm/. 3.NBC 2020 & BCBC 2024, Parts 9 and 4. 4.Environment Canada, Climatic Design Criteria. Calculating vector force and vertical force snow loads on metal roofing. The S-5! approach calls for thorough testing and consistency.Next >