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Outboard Insulation: Basement and Wall Strategies for Southern Ontario

With the popularity of brick and stone veneer claddings in the Southern Ontario new construction housing market, the code-driven trend of outboard insulation strategies creates some challenges for builders. Builders have grown accustomed to the ease of construction and costs associated with 8” cast-in-place foundation walls. Outboard insulation strategies, while efficient from a thermal perspective in our climate zone, can create foundation wall depth issues, e.g. maintaining bearing for heavyweight veneers, and the 1” drainage gap required by these wall types to vent bulk water. Through a series of residential design workshops sponsored by the Enbridge Gas Distribution’s Savings By Design program, a clear link to cost as a primary objection has surfaced amongst most (80%) of builder proponents questioned. This paper describes seven above ground and basement wall strategies, options which rely on a typical 8” foundation pour (some requiring enhanced rebar schedules) and which utilize outboard insulation between 2” to 4” thickness with masonry veneer claddings. This outboard insulation strategy, along with balanced interstitial insulation levels, meets the standard for net zero ready housing and will likely be code compliant construction by 2030 in Ontario. Criteria for applying these building strategies included ease of construction, durability of wall systems, and thermal and structural performance. Order-of-magnitude pricing, including local labour factors, have been included for each system and may be compared and contrasted with the more typical 10” foundation strategy to determine which approach makes greater holistic sense.

Authored by Dave Petersen & Miyoko Oikawa

Natalia Ortiz Moreno

Natalia Ortiz, student of Project Management Environmental (PME) program in Seneca Polytechnic, has an Environmental Engineering background completed at Universidad El Bosque in Colombia. She has always been involved in sustainability roles and projects that included Environmental Management Systems implementation, Water Treatment Systems’ design and operation, Hazardous and Conventional Waste management and minimization practices, as well as Ecosystem’s Conservation and Energy
Efficiency programs.

For the PME – Applied Project Management Course, Natalia developed a Green Roof Assessment Tool for Seneca Polytechnic’s Office of Sustainability, with the aim to provide green roof technology recommendations best suited to a particular scenario, taking into consideration multiple aspects of green roofs and buildings; infrastructure, design, materials, environmental factors, and costs, as well as the Toronto Municipal Code – Green Roof bylaw. Natalia also has a scientific journal publication as the main author of the project “Selection and sizing of industrial wastewater treatment units required at the
new maintenance, repair, and overhaul (MRO) aircraft facility owned by Avianca S.A. in Rionegro Antioquia” in the El Bosque University Journal of Technology.

Natalia strongly believes there are several research topics left to be developed, and the importance of
working towards Sustainability from different backgrounds, knowledge, and cultures to build strong, productive, and resilient communities.
With the vision of growing cities and infrastructure along with nature, always preserving and respecting the ecosystems’ attributes and services, Natalia would like to keep researching and acquiring more experience in Sustainability roles.



Emily Smit

Emily is a second-year PhD student in Geography at the University of Toronto, and a co-operator of a small home renovation company, Magnus Home Improvements. Her research seeks to determine how single-family homes can quickly and best be retrofit to achieve Toronto’s emissions reductions targets – including net-zero by 2040 – as part of the TransformTO climate action plan. Specifically, she will assess the impact of municipal home energy reporting and disclosure programs, as well as produce recommendations for growing the retrofit labour force in ways that attend to the UN Sustainable Development Goals. Further, her research seeks to understand how home retrofit activities can be regenerative and produce net-positive impacts for humans and the environment towards transformative, place-based sustainability. When not at her computer, Emily can be found cycling with her kids to and from school or making funky sounds on her analog synthesizer.

Bofa Udisi

Bofa is a sustainability professional with over seven years in the energy and environment industry. He has a Bachelor of Science in Energy and Petroleum Studies from Novena University in Nigeria and graduate certificates in Energy Management and Environmental Project Management from Seneca College in Toronto. In 2020, he graduated from the University of Waterloo with a Master of Environment and Business degree. He is currently a Ph.D. Candidate in the Building Science program at Toronto Metropolitan University, researching whole-life carbon reduction in new construction and building renovations.

Bofa‘s work experience is primarily in the built environment, working in the private and public sectors in roles that involve structural and environmental assessment of building structures, HVAC engineering design and sales, and facilities management. Bofa is a member of several industry associations, such as the Association of Energy Engineers (AEE), the American Society for Heating Refrigeration and Air Conditioning Engineers (ASHRAE), and the Project Management Institute (PMI). SBC’s bursary will go a long way in supporting Bofa‘s research and his desire to learn.