The Triple Bottom Line of Structural Materials: Cost, Speed and Life Cycle Assessment<\/em><\/h3>\n![\"-\"](\"https:\/\/www.on-sitemag.com\/wp-content\/uploads\/2026\/01\/Saunders1.jpg\")
<\/p>\nPhoto by Peter Saunders.<\/p>\n<\/div>\n
WSP<\/a>, mcCallumSather<\/a> and ArcelorMittal<\/a> unveiled the results of a theoretical case study at The Buildings Show<\/a> in December, which showed the costs and sustainability of using steel, concrete or timber are similar for a typical 12-storey, 287,000-sf, L-shaped residential condominium tower in the Greater Toronto Area (GTA).<\/p>\nA conference session titled \u2018The Triple Bottom Line of Structural Materials: Cost, Speed and Life Cycle Assessment\u2019 featured Brant Oldershaw, P.Eng., WSP\u2019s director of structural, mechanical and electrical engineering for Southwestern Ontario; Willems Ransom, principal and architect for mcCallumSather; Matthew Winters, P.Eng., Steligence project manager for ArcelorMittal; and Mike Cortese, principal sustainability projects manager for ArcelorMittal.<\/p>\n
As they explained, WSP and mcCallumSather joined steel producer ArcelorMittal\u2019s Steligence program to model and compare the performance of different building materials for the same theoretical project. Consulting engineering firms RJC<\/a> and MTE<\/a> also contributed to the project\u2019s structural details.<\/p>\n\u201cWe were not designing a building, but a case model,\u201d Ransom explained. \u201cIt was normalized for the market, but optimized to no single solution. It was flexible, with a typical building envelope and massing.\u201d<\/p>\n
While they developed and tested the virtual models, they estimated the project\u2019s structural weight, total cost, speed of construction and environmental impact.<\/p>\n
\u201cOriginally, we only compared steel and concrete frame systems,\u201d said Winter. \u201cNow, we added a mass-timber scenario, where it\u2019s more challenging to ensure functional equivalency.\u201d<\/p>\n
\u201cMass timber is more spatially intensive and lends itself to certain spans,\u201d Willems explained, \u201cbut we maintained the same functional floor plan as much as possible across the various options.\u201d<\/p>\n
\u201cWe kept it as generic as we could,\u201d said Oldershaw, \u201cwith commonalities like concrete foundations and cast-in-place concrete for stairwells.\u201d<\/p>\n
To assess environmental impact, they conducted life-cycle analysis (LCA) calculations at each stage, including data from third-party-verified Environmental Product Declarations (EPDs) and focusing on global warming potential (GWP).<\/p>\n
\u201cWe used One Click LCA software to compare three functionally equivalent buildings,\u201d said Cortese. \u201cWith the EPDs, we \u2018sourced\u2019 local products where possible. The number of EPDs available is growing exponentially, which makes this work easier to do and more accurate.\u201d<\/p>\n
\u201cI thought there\u2019d be a bigger gap on LCA,\u201d said Oldenshaw.<\/p>\n
![\"-\"](\"https:\/\/www.on-sitemag.com\/wp-content\/uploads\/2026\/01\/Saunders2.jpg\")
<\/p>\nPhoto by Peter Saunders.<\/p>\n<\/div>\n
The three main structural materials considered were ArcelorMittal\u2019s own XCarb recycled and renewably produced (RRP) steel; a ready-mix average with general use low-carbon (GUL) concrete, per Concrete Ontario standards; and a combination of British Columbia glue-laminated (glulam) timber and Ontario cross-laminated timber (CLT).<\/p>\n
The resulting GWP was similar in all three scenarios; slightly higher for concrete, followed by mass-timber, followed by steel. In each case, however, construction proved achievable within the stipulations of the Toronto Green Standard (TGS).<\/p>\n
\u201cThe close results surprised me,\u201d said Cortese. \u201cIt came down to consistency in philosophy, design and material selection.\u201d<\/p>\n
\u201cAs we tried to reduce embodied carbon for this case study,\u201d Winters said, \u201cwe realized when we\u2019re designing well and using materials to their strengths, we can hit our sustainability targets with any material.\u201d<\/p>\n
The estimated costs were similar, too, with steel coming in at $3,107,500, concrete at $3,121,500 and timber at $3,011,000.<\/p>\n
\u201cWe put timber into an unusual context with this project,\u201d says Ransom from his perspective as architect, \u201cbut realized it\u2019s becoming a more equitable option that can be comparable to steel and concrete.\u201d<\/p>\n
The main point of difference was the time needed for construction. While each project involved 40 days for the foundation and 70 days for cladding, from there, timber won the race at 113 days for the structure, followed by steel at 157 days and concrete at 190 days.<\/p>\n
Looking back at the project as an experiment, Ransom pointed to both the benefits and disadvantages of the multi-party collaboration that was required.<\/p>\n
Willems Ransom: LCAs are easier to produce and there\u2019s better software, but that leads to much more difficult decision-making process, which is positive.<\/p>\n
\u201cWe used to design by rules of thumb,\u201d he said. \u201cDefine the critical factors of impact demands a different level of investigation in the design process, which is greatly enhanced through collaboration with industry partners. We have data to mine now, but it\u2019s changing at a rapid pace. So, we need to start to define processes to streamline decision-making. Integrated Project Design (IPD) is an ideal scenario, but takes a lot of time and people!\u201d<\/p>\n<\/div>\n
<\/p>\nPhoto by Peter Saunders.<\/p>\n<\/div>\n
WSP<\/a>, mcCallumSather<\/a> and ArcelorMittal<\/a> unveiled the results of a theoretical case study at The Buildings Show<\/a> in December, which showed the costs and sustainability of using steel, concrete or timber are similar for a typical 12-storey, 287,000-sf, L-shaped residential condominium tower in the Greater Toronto Area (GTA).<\/p>\n A conference session titled \u2018The Triple Bottom Line of Structural Materials: Cost, Speed and Life Cycle Assessment\u2019 featured Brant Oldershaw, P.Eng., WSP\u2019s director of structural, mechanical and electrical engineering for Southwestern Ontario; Willems Ransom, principal and architect for mcCallumSather; Matthew Winters, P.Eng., Steligence project manager for ArcelorMittal; and Mike Cortese, principal sustainability projects manager for ArcelorMittal.<\/p>\n As they explained, WSP and mcCallumSather joined steel producer ArcelorMittal\u2019s Steligence program to model and compare the performance of different building materials for the same theoretical project. Consulting engineering firms RJC<\/a> and MTE<\/a> also contributed to the project\u2019s structural details.<\/p>\n \u201cWe were not designing a building, but a case model,\u201d Ransom explained. \u201cIt was normalized for the market, but optimized to no single solution. It was flexible, with a typical building envelope and massing.\u201d<\/p>\n While they developed and tested the virtual models, they estimated the project\u2019s structural weight, total cost, speed of construction and environmental impact.<\/p>\n \u201cOriginally, we only compared steel and concrete frame systems,\u201d said Winter. \u201cNow, we added a mass-timber scenario, where it\u2019s more challenging to ensure functional equivalency.\u201d<\/p>\n \u201cMass timber is more spatially intensive and lends itself to certain spans,\u201d Willems explained, \u201cbut we maintained the same functional floor plan as much as possible across the various options.\u201d<\/p>\n \u201cWe kept it as generic as we could,\u201d said Oldershaw, \u201cwith commonalities like concrete foundations and cast-in-place concrete for stairwells.\u201d<\/p>\n To assess environmental impact, they conducted life-cycle analysis (LCA) calculations at each stage, including data from third-party-verified Environmental Product Declarations (EPDs) and focusing on global warming potential (GWP).<\/p>\n \u201cWe used One Click LCA software to compare three functionally equivalent buildings,\u201d said Cortese. \u201cWith the EPDs, we \u2018sourced\u2019 local products where possible. The number of EPDs available is growing exponentially, which makes this work easier to do and more accurate.\u201d<\/p>\n \u201cI thought there\u2019d be a bigger gap on LCA,\u201d said Oldenshaw.<\/p>\n Photo by Peter Saunders.<\/p>\n<\/div>\n The three main structural materials considered were ArcelorMittal\u2019s own XCarb recycled and renewably produced (RRP) steel; a ready-mix average with general use low-carbon (GUL) concrete, per Concrete Ontario standards; and a combination of British Columbia glue-laminated (glulam) timber and Ontario cross-laminated timber (CLT).<\/p>\n The resulting GWP was similar in all three scenarios; slightly higher for concrete, followed by mass-timber, followed by steel. In each case, however, construction proved achievable within the stipulations of the Toronto Green Standard (TGS).<\/p>\n \u201cThe close results surprised me,\u201d said Cortese. \u201cIt came down to consistency in philosophy, design and material selection.\u201d<\/p>\n \u201cAs we tried to reduce embodied carbon for this case study,\u201d Winters said, \u201cwe realized when we\u2019re designing well and using materials to their strengths, we can hit our sustainability targets with any material.\u201d<\/p>\n The estimated costs were similar, too, with steel coming in at $3,107,500, concrete at $3,121,500 and timber at $3,011,000.<\/p>\n \u201cWe put timber into an unusual context with this project,\u201d says Ransom from his perspective as architect, \u201cbut realized it\u2019s becoming a more equitable option that can be comparable to steel and concrete.\u201d<\/p>\n The main point of difference was the time needed for construction. While each project involved 40 days for the foundation and 70 days for cladding, from there, timber won the race at 113 days for the structure, followed by steel at 157 days and concrete at 190 days.<\/p>\n Looking back at the project as an experiment, Ransom pointed to both the benefits and disadvantages of the multi-party collaboration that was required.<\/p>\n Willems Ransom: LCAs are easier to produce and there\u2019s better software, but that leads to much more difficult decision-making process, which is positive.<\/p>\n \u201cWe used to design by rules of thumb,\u201d he said. \u201cDefine the critical factors of impact demands a different level of investigation in the design process, which is greatly enhanced through collaboration with industry partners. We have data to mine now, but it\u2019s changing at a rapid pace. So, we need to start to define processes to streamline decision-making. Integrated Project Design (IPD) is an ideal scenario, but takes a lot of time and people!\u201d<\/p>\n<\/div>\n<\/p>\n