ROOF RESURFACING: BENEFITS AND OPPORTUNITIES
Owner: Cadillac Fairview
Contractor (roofer): A-Tech Roofing Ltd
Consultant: WSP Canada, Inc.
SOPREMA representative: Daniel Robichaud
Type of solution: Waterproofing
Type of work: Resurfacing
Resurfacing surface area: 16,304 m2 (175,500 ft2)
Works duration: 2019 to 2022
City: Dieppe (NB)
Warranty: MAMMOUTH GENERATIONS
SUMMARY: Resurfacing a roof has multiple economical and environmental benefits. The real estate developer Cadillac Fairview, the consulting firm WSP Canada, Inc. and SOPREMA chose this solution in order to ensure the durability of part of the roof of the CF Champlain Mall located in Dieppe, New Brunswick. The works were carried out over an area of 16,304 m2 (175,500 ft2) of the roof, which has a total area of approximately 92,903 m2 (1,000,000 ft2). The resurfacing technique has avoided the transport of more than 160 waste containers to a landfill site and reduced greenhouse gases linked to production and transport by 67%. SOPREMA is proud to have been a partner in this major project.
RESTORING A ROOF TO EXTEND ITS LIFETIME
The design and specification of a roof should be guided by energy savings, sustainability, optimal use of raw materials, and waste reduction. For 20 years, SOPREMA has been offering a solution that consists of covering an existing waterproofing system. This resurfacing technique extends the useful life of a roof and reduces the amount of material sent to landfills.
This was the choice made by the real estate developer Cadillac Fairview, the consulting firm WSP Canada, Inc. and the manufacturer SOPREMA to ensure the durability of part of the roof system of the CF Champlain Mall located in Dieppe, New Brunswick.
With a total area of nearly 92,903 m2 (1,000,000 ft2), it is the largest mall in New Brunswick.
Carried out in four phases (2019 to 2022), the resurfacing work over an area of 16,304 m2 (175,500 ft2) is bringing significant environmental and economic benefits; the complete replacement of the roofing system would not have achieved such results.
THE LARGEST SHOPPING CENTRE IN NEW BRUNSWICK
MITIGATION OF ENVIRONMENTAL IMPACTS
The mitigation of environmental impacts is very important in this large-scale project. Indeed, resurfacing not only extends the service life of the roof, but also reduces the quantity of waste, materials, greenhouse gas (GHG) emissions as well as energy consumed in the manufacture and transport of materials.
A Roof That Can Reach 100 Years Old
Built in 1974, the old roofing system (asphalt and gravel) was 25 years old when it underwent a first complete replacement in 1999, when it was replaced by the new SBS-modified bitumen membrane system by SOPREMA.
“After evaluation, we determined that this roofing system was the best solution due to its durability and long-term resurfacing possibilities,” said Jean-Guy Levaque, Senior Roofing Specialist at WSP Canada, Inc.
*Typical resurfacing requires only one cap sheet membrane, but in this case, the owner and the consultant chose to apply two layers of membrane—a base sheet membrane and a cap sheet membrane—to enhance the performance of the building.
Although the lifespan of the materials in resurfacing generally varies from 25 to 30 years, “the real estate developer CF Champlain decided to be proactive and perform a first resurfacing after 20 years in 2019. Doing so did not require the replacement of the existing roof system, that is to say the vapour barrier, the insulation, the support panel, and the two-ply system,” pointed out Daniel Robichaud, Director – Atlantic Provinces at SOPREMA.
Compared to a complete replacement, this first resurfacing extended the life of the existing system by at least 25 years.
This project made it possible to carry out two more resurfacings in the future. These potential works would extend the life of the existing system by 50 to 60 years. Considering that this one is already 20 years old and another 25 years was added to the first resurfacing in 2019, this would mean that the roof system could reach a 100-year service life1.
160 Waste Containers Avoided
By opting for resurfacing, the vision of WSP and SOPREMA was clear: to offer a sustainable and environmentally friendly solution for current and future generations.
At the time, “No one knew what was going to happen to the current roofing system. The components were heavy, and we were aware that few materials were recyclable. It was difficult to predict whether landfills would continue to accept these products. We therefore had to think of a solution based on sustainable development,” stated Philippe Thériault, Operations Manager at CF Champlain.
The resurfacing of part of the roof of the CF Champlain Mall made it possible to avoid the transport of more than 160 waste containers2 to a landfill, which represents approximately 240 metric tonnes of residual materials that would have been generated by a complete replacement.
This solution has also reduced by 31% the amount of raw materials required.
Reduction of 80% in Truck Transport
This work made it possible to reduce by 80% the number of truck trips to bring materials to the site. Indeed, only 5 shipments of 53-foot trucks were needed for the resurfacing, whereas a complete replacement would have required 25 shipments.
This represents a total of 18,000 km of travel avoided.
Reduction of Greenhouse Gases by 67%
In addition, the volume of GHG emissions avoided thanks to this resurfacing is considerable. We calculate a reduction of 67% of greenhouse gas (GHG) emissions3 linked to the production of materials and their transport to the site.
- Complete replacement: 11.3 t CO2 eq.
- Resurfacing: 3.7 t CO2 eq.
- 67% of GHGs avoided (7.6 t CO2 eq.)
All in all, the case study reveals that resurfacing can significantly mitigate, delay, or even prevent some environmental impacts. Being a form of reduction at the source, it is a simple solution that also increases the durability of the structure.
SAVING TIME AND MONEY
Another notable benefit of resurfacing is that it reduces the time required to complete the work and lowers the cost of materials.
Materials: 45% to 50% Savings
Compared to a complete replacement, resurfacing helps reduce the purchase costs of new materials by 45% to 50%. From a long-term perspective, this represents considerable savings which increase with the frequency and number of resurfacings required.
Time: 35% Savings on Site
When compared with a complete replacement, resurfacing has reduced the time required to carry out work on site by approximately 35%. Marc G. Leblanc, P.Eng. and Manager of NB Operations, GSC, at A-Tech Roofing Ltd, emphasizes that “resurfacing required 26 weeks of work instead of an estimate of 40 weeks for complete replacement.”
OPTING FOR PEACE OF MIND
In addition to the many environmental and economical benefits, resurfacing provides true peace of mind. In fact, the period of exposure to noise is shorter and this generates little or no service interruptions of business activities. “The impact was drastically reduced, so tenants and customers didn’t even realize we were replacing sections of the roof,” says Philippe Thériault, Operations Manager at CF Champlain.
Visual pollution was also reduced, such as waste containers, delivery trucks and cranes on site. This peace of mind is highly valuable for property owners like us. We are extremely proud of our mall. We take care of it and it sets a great example for others. This is our first roof resurfacing, and everything is working as expected. This is the perfect scenario!”
To learn more about the environmental benefits of this project, please read the article from our expert in sustainable development: Increasing the Durability of a Roofing System Through Resurfacing.
1 Although the frequency of works and the number of resurfacings are at the discretion of the customer, it is likely that the physical integrity of the cap sheet membrane will be greater than that covered by the selected warranty. The number of resurfacings is also determined by the estimated capacity of the building structure. The physical integrity of the roofing system materials can influence the frequency and nature of the work.
2 This number was estimated and based on one container with a capacity of 40 cubic yards (20 ft × 8 ft × 8 ft).
3 The estimate of GHG emissions is based on the following parameters and sources: Environment and Climate Change Canada (2019). National Inventory Report (1990 to 2017). | Environment and Climate Change Canada (2017). National Inventory Report (1990 to 2015). | Intergovernmental Panel on Climate Change (IPCC) (2006). Guidelines for National Greenhouse Gas Inventories, Vol. 5: Waste, Chap. 4: Biological Treatment of Solid Waste.