Aluminum mill shape prices climbed 27.3% year over year in August, according to the Aluminum Prices Surge 27% as Tariffs Pressure Construction Costs report from USGlass magazine. That surge, combined with new cross-border tariffs between Canada and the United States, is squeezing Canadian glazing fabricators and installers that depend on aluminum for curtain wall, window and door systems.
The price increase was part of broad metal inflation captured in the U.S. Bureau of Labor Statistics Producer Price Index. Steel mill products rose 23.4% and copper and brass mill shapes jumped 20.9% over the same 12-month period. Those higher input costs predate Canada’s aluminum counter-tariffs in early September, which layered new duties on top of already volatile frame and hardware costs.
Tariff escalation hits both sides
According to the Canada's retaliatory tariffs on American goods are now in effect report by The Canadian Press, Ottawa’s retaliatory tariffs took effect just after midnight EDT on Sept. 8, 2026, responding to Washington’s 50 per cent tariffs on Canadian goods imposed Aug. 22. The Canadian Press report says Canada’s reciprocal tariffs target the same value of U.S. goods, and include a 50 per cent tariff on multiple steel and aluminum products, up from the current 25 per cent rate. Those products include door and window frames, among other prefabricated items.
The primary USGlass magazine report notes that the U.S. imposed a 50% tariff on roughly $20 billion of Canadian exports, while Canada implemented retaliatory tariffs ranging from 15% to 50% on approximately $20 billion worth of U.S. goods. Canada increased tariffs on aluminum and steel, ranging from 25% to 50%, as part of the counter-tariffs. The Canadian Press report, however, says Washington launched tariffs on nearly $28 billion of Canadian goods on Aug. 22, a dollar figure that differs from the USGlass account; both reports confirm steep new duties on metals used in fenestration.
“We couldn’t accept what they offered. We wouldn’t give what they’d asked. As a result, the U.S. has imposed new tariffs designed to hurt and divide us,” Prime Minister Mark Carney said last week, according to the Canadian Press. “Now, that’s a miscalculation because Canadians will always take care of each other. And it’s a miscalculation because we have everything we need to build the country we want. We have the reserves, we have the resilience, and we have the right plan.”
Fenestration products caught in the tariff net
Fenestration Canada reports that several fenestration products imported from the U.S. were included in Canada’s rebuttal, according to the Aluminum Prices Surge 27% as Tariffs Pressure Construction Costs report. The list includes aluminum doors, windows, frames and thresholds; iron or steel doors, windows, frames and thresholds; and iron and steel fasteners, which face 50% tariffs. Base-metal mountings and fittings for doors and windows face a 25% tariff. These components sit inside many curtain wall and storefront assemblies, so any import duty change flows directly into bid pricing.
Existing price pressure already acute
The Producer Price Index data show that metal window prices were unchanged in August but remained 12.2% higher than August 2025. Ornamental and architectural metalwork prices rose 0.6% in August and were up 9.9% year over year. Fabricated structural metal products increased 0.5% in August and stood 6.5% higher than the same period a year earlier. Builders’ hardware prices declined 0.1% in August but were still up 4.8% year over year. Those increases are dwarfed by the 77.8% year-over-year jump in diesel fuel, which raises delivery and equipment costs across the construction supply chain.
“Construction firms are being squeezed by tariff- and war-induced materials cost increases, even as they boost wages to attract personnel,” says Ken Simonson, AGC’s chief economist. “Those cost increases, according to our latest survey, are a major reason project owners are canceling, postponing or scaling back projects.”
New nonresidential construction activity actually rose 8.9% from August 2025 to August 2026, according to the PPI report, but the AGC warning suggests rising costs are now chipping away at that pipeline. For Canadian glazing fabricators, a slowdown in U.S. nonresidential work could reduce export demand at the same time tariffs make cross-border selling harder.
Tariff uncertainty changes bid strategy
Melissa Irmen, director of advocacy for the National Association of Foreign-Trade Zones, told CNBC that continued uncertainty around tariffs will permanently change the business landscape. “Companies are not able to make the fast decisions required for the tariff changes,” she explains. “Supply chains don’t work that way. We tell our members that things will not go back to the way they were pre-2025. Try to look as long-term as you can.”
For Canadian fabricators, the tariff line item has moved from contingency to fixed cost. The Canadian Press report confirms that multiple steel and aluminum products, including door and window frames, are now hit with a 50 per cent tariff, up from 25 per cent. Importers that source U.S. aluminum doors, windows or frames must now price that duty into bids, and any project assumptions about stable material costs are out of date. The primary report notes that flat glass prices rose just 0.1% in August and were up 2.8% year over year, but metal components are the larger risk for curtain wall budgets.
As long as both countries keep the new tariffs in place, Canadian glazing contractors will need to update bid templates, review supplier agreements and build escalation clauses into long-term contracts. The data show the pressure is not a one-month blip: aluminum mill shapes are up 27.3% year over year, metal windows up 12.2%, and ornamental metalwork up 9.9%, with new duties layered on top.