Pressure Treated Lumber ACQ...


ACQ Lumber  Replaced CCA Treated Lumber

Why is CCA lumber no longer being sold?
In early 2004, Sutherlands, along with most other retail lumber dealers in the United States, began phasing in ACQ (Alkaline Copper Quaternary) lumber to replace CCA & Wolmanized lumber. The Preservative manufacturers are voluntarily taking this action based on negative public perception of CCA, media coverage and growing consumer interest in using an alternate wood preservative.

What is ACQ Lumber?
ACQ is a copper based preservative system that is the most cost-effective alternative to CCA. ACQ has been researched and tested since the late 1980's. It was introduced commercially in 1992. ACQ provides dependable performance and is building code compliant (NER 628). It treats a wider range softwood lumber species, and is quality assured by a third party (TPI or SPIB). Like CCA, it is treated against decay and insect damage.

What is ACQ lumber approved for?
ACQ is ideal for structural uses, sill plates, outdoor furniture, playground equipment, patios, decks, garden edging and landscaping structures. The preservatives in ACQ products meet American Wood Preservers Association standards.

Are there different grades of ACQ lumber?
Yes. The same formula used for CCA lumber applies to ACQ treated lumber for the following applications:

  • Above Ground (.25)
  • Ground Contact (.40)
  • Fresh Water Contact (.40)

Can I use the same metal fasteners as CCA lumber?
The chemicals used in ACQ will corrode ordinary galvanized fasteners, therefore special consideration must be taken when working with ACQ lumber. Hot dipped or stainless steel fasteners MUST be used with ACQ.

The following products are available at most Sutherlands locations for use with ACQ products. Manufacturers recommend these lines of product to be used with ACQ treated lumber:

  • Simpson Strong-Tie - ZMAX (G185) Hot-Dip Galvanized or Stainless steel fasteners
  • USP Structural Connectors - Triple Zinc G-185 Connectors
  • Prime source Fastening Systems - Prime Guard Plus - Coated Fasteners

Please note: One-half inch (12.7mm) or greater steel bolts are acceptable and do not require special coatings.

Aluminum should not be used in direct contact with ACQ preserved wood. Spacer materials or some other physical barrier are recommended to prevent direct contact. A poly barrier is recommended for any applications where ACQ will meet aluminum flashing. Do not use aluminum fasteners.

Will ACQ lumber look the same as CCA?
When purchased, freshly treated ACQ is the familiar green color like CCA. It will weather to a tan/brown color in months and eventually weather to gray over time.

For more information, check these other resources:

Simpson Strong-Tie
USP Connectors

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