Tariff Shift

Trump Revises 50% Tariffs on Canadian Building Materials

Latest changes remove certain Canadian plywood from 50% tariffs while adding paints, mastics and other products that could reach roofing and construction

Official White House Photo/Daniel Torok

President Donald Trump delivers remarks on tariffs at the White House on Feb. 20, 2026.

The Trump administration is again reshuffling the list of Canadian imports subject to an additional 50% tariff, removing some products while adding others with potential implications for roofing contractors and suppliers.

President Donald Trump signed an Oct. 23 proclamation modifying tariffs imposed under Section 338 of the Tariff Act of 1930. The latest changes take effect at 12:01 a.m. Eastern on Oct. 30.

The changes continue to alter the picture RC outlined in July, when it reported that selected Canadian construction products could face the additional duty. The administration has since narrowed and revised that original list. In September, the administration removed Portland cement, one of the construction products highlighted in RC's initial reporting, from the Section 338 tariffs. The latest revision removes several classifications of thin plywood sheets from the 50% duty, potentially reducing the tariff exposure for some Canadian wood products. The exemptions cover specific plywood classifications with sheets no more than 6 millimeters thick, meaning contractors and suppliers should not assume that all Canadian plywood or roof decking products qualify.

At the same time, the administration is adding other construction-related products to the tariff list. Those include nonaqueous acrylic- or vinyl-polymer paints and varnishes, as well as caulking compounds, mastics, resin cements and painters' fillings. The new classifications also cover certain polyurethane products, fiberboard, and continuously shaped coniferous wood. Some of those classifications could encompass products used in roofing, waterproofing or building-envelope applications, depending on the product's specific Harmonized Tariff Schedule code. Importers and contractors should verify classifications with suppliers or customs professionals rather than relying on general product descriptions.

The White House said the changes are intended to refine tariffs first announced in July in response to what the administration describes as Canada's discriminatory treatment of U.S. commerce. Covered goods remain subject to the additional 50% duty even if they otherwise qualify under the U.S.-Mexico-Canada Agreement. The administration also said Section 338 duties apply in addition to applicable Section 232 tariffs.

The White House published Annex I and Annex II, which detail the specific tariff classifications affected by the latest changes.

The shifting product list reinforces advice construction attorney Trent Cotney gave RC following the original announcement: contractors should monitor material pricing, review escalation and substitution provisions in contracts, and determine whether specified Canadian products could be affected.

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Tanja Kern is director of content strategy and managing editor for Roofing Contractor. She covers economic trends and the intersection of architecture, design, and construction, focusing on the forces reshaping the industry. She develops and amplifies content that connects roofing professionals with the intelligence they need to compete and grow.

With more than 20 years of experience, Tanja has written for national business, consumer and trade publications. She holds a Master of Science in magazine publishing from Northwestern University's Medill School of Journalism.