Not uniformly , sourcing varies by manufacturer. Metal Pro Buildings, an authorized Pioneer Steel dealer based in Thornhill, Ontario, sources steel from ArcelorMittal Dofasco, one of Canada’s primary domestic steel producers. Domestic sourcing insulates buyers from the cross-border tariff volatility that has pushed imported structural steel costs higher since 2024, and supports CSA A660 certification, Canada’s national standard for cold-formed steel building systems.