What are Pressure Treated and ACQ lumber?

Pressure Treated Wood

Pressure-treated wood is softwood lumber, typically southern yellow pine, that's been chemically treated to resist rot, decay and termites. The boards are rolled into giant pressurized tanks where chemical preservatives are forced deep into the wood's fibres.


ACQ is an arsenic and chromium-free wood preservative made of copper oxide and a quaternary compound. It was introduced in North America in 1992 and has a 20-year history of safe, effective use.   Registered by the PMRA of Health Canada, ACQ is the most widely-sold pressure-treated wood in Canada.  ACQ pressure-treated wood is also standardized by the Canadian Standards Association (CSA-O80) and meets all applicable major model building code requirements in Canada.

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