THE ONLY SOURCE FOR PROFESSIONAL ICI ROOFING CONTRACTORS IN ONTARIO ORN
18 
ONTARIO ROOFING NEWS – ISSUE 1 2026
Building 1
Building 2
Building 3
Roof area m2 (ft2)
39,019
(420,000)
50,725
(546,000)
99,964
(1,076,000)
Roof re-covering project cost savings compared to roof replacement (~%)
22%
22.7%
22%
Roof re-covering V.2 project cost savings compared to roof replacement (~%)
24%
23.2%
25%
Figure 2: Existing built-up roof membrane removed and localized “wet” insulation being replaced.
Table 2: Tender (bid) results summary.
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• Roofing
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• Building Envelope
• Asphalt & Concrete Pavements
• Windows & Doors
• Structural Engineering
• Mechanical Engineering
• Electrical Engineering
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905-639-1911
Roof Restoration
Figure 3: New roof re-cover system installed.
cost compared to their base sheet 
membrane and asphaltic board 
counterparts.
All three design scenarios were 
tendered (bid) to six contractors 
across three warehouse buildings, 
including the building reviewed for 
the aforementioned embodied car-
bon calculations. Contrary to the 
initial expectation that these lower-
embodied-carbon materials might 
increase overall construction cost, 
contractor bids collectively reflected 
significant project cost savings com-
pared to the base design. Tender re-
sults of the project are summarized 
below and in Table 2:
• Scenario 2 (Roof Re-Cover/
Renewal): Achieved approxi-
mately 22 to 23-per-cent 
project cost savings compared 
to full replacement.
• Scenario 3 (Roof Re-Cover/
Renewal 
V.2 
[Embodied 
Carbon Optimized]): Deliv-
ered even greater savings, rang-
ing from 23 to 25 per cent. 
Discussions with contractors 
provided key insights into these un-
expected overall savings passed on to 
the client: 
• Economies of Scale: The vast 
roof area enabled contractors 
to secure more competitive 
pricing from manufacturers 
and suppliers due to large ma-
terial quantities.
• Material Dimensions and 
Labour Efficiency: The larger 
dimensions of the base sheet 
membrane panels (3 ft × 8 ft) 
and gypsum boards (4 ft × 8 
ft) compared to standard 4 ft 
× 5 ft asphaltic overlay boards 
significantly reduced labour 
time, especially on a largely 
unobstructed roof with a low 
number of penetrations. This 
enhanced 
labour 
efficiency 
proved to be the primary factor 
contributing to the reduced to-
tal project cost, effectively off-
setting any higher per-unit ma-
terial costs. The tender results 

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