Environmental advantages and economic enhancement are key reasons as to why mass timber buildings are literally on the rise in cities like Toronto.
Anticipate 10 to 12 mass timber multi-storey housing projects to emerge along main streets in the city in 2022, states Leith Moore, principal and founder of R-Hauz Solutions Inc., the company building Ontario’s first six-storey mass timber residence, a pilot finished recently on Queen Street East in the Beach neighbourhood of Toronto.
Among the panellists at a mass timber seminar hosted by the Carpenters’ District Council of Ontario in Woodbridge, Moore and R-Hauz are trailblazers, paving the way for other residential builders in mass timber.
The company and its design team devoted two years to design details, such as talks with the city’s planning and building departments, to achieve alternative solutions for building code compliance. Among those solutions are cross-laminated timber stairs and elevator cores.
The key to success in the new medium is to blend “repeatability” so tomorrow’s buildings can economically and quickly be designed and constructed, Moore told a packed room. For many delegates it was the initial large-scale face to face event in nearly two years.
Panellist David Moses, principal of Moses Structural Engineers Inc., the engineer for the pilot, said the project establishes a precedent and he praises R-Hauz for taking the risks to construct the project.
Moore said that a component in the success of small mass timber housing (20,000 square feet or less) is adapting an Integrated Project Delivery model which “locks in performance” for similarly sized projects at a future time.
Mass timber has advanced in Canada since 2009 when Moses Structural consulted on the premiere CLT project in North America, a small structure in Whistler, B.C., for the 2010 Olympics. The engineer referenced Europe for materials and design methodologies. Now provinces like Ontario are universal leaders in mass timber design and manufacturing, said Moses.
Mark Gaglione, director of construction sciences with EllisDon, stated critical elements in construction encompass moisture management.
EllisDon also carried out a moisture testing program at one of its sites, evaluating coatings, membranes and toppings and its sustainability team has finished a myriad of life-cycle reviews.
The contractor has attained additional insight into moisture issues at Scarborough’s Centennial College, a 105,000-square-foot mass timber project it has partially built through winter and fall.
Gaglione stated that sharing its experiences with other contractors and designers is valuable “because we want more of these buildings built so there will be more success stories out there.”
He said EllisDon’s research department has developed a hybrid timber panel system for office buildings needing 40-foot-long spans. He says they want to stop pushing boundaries and limits in this area.
Still in its initial stage, the panel will conduct fire and structural testing and EllisDon has partnered with federal agencies to support through the research stages in the near future.
The general contractor plans to introduce new mass timber approaches in the residential world arising from work at its manufacturing plant in Hamilton.
In regards to construction insurance, Gaglione told delegates insurance now attained through European carriers is less than the GC was paying 10 years ago when paying 10 times more than concrete structures was customary, through insurance remains expensive for mass timber.
Insurers limit capacity exposures to $5 to $20 million, an issue for EllisDon’s $50 to $100 million projects.
EllisDon’s internal brokerage has cooperated with carriers to bundle subscription policies to enhance capacity coverage on major projects. The contractor employs moisture management strategies and fire prevention methods to lower insurance expenses.
Deeming mass timber’s economic “sweetspot” in residential building at likely 8 to 12 storeys, Moses stated that developing computing capabilities and modelling will enhance efficiencies in building sectors for the industry to develop.
Imsge source: istockphoto.com