
Real Wood for Your Outdoor Spaces
Proven Long-term Protection
Preserve® is a family of fully-dissolved copper-based wood preservative solutions for exterior wood products. Preserve formulations provide long-term protection from fungal decay and termite attack for a wide variety of residential, commercial and agricultural construction projects including above-ground, ground contact, fresh-water immersion, and salt-water splash applications.
In the US and other countries, CA-C, CA-B and ACQ are registered for use on: lumber, timbers, landscape ties, fence posts, building and utility poles, land, freshwater and marine pilings, seawalls, decking, wood shingles, and other wood and wood framing structures.
The Preserve treatment lends a distinctive green tint to the timber, although an additional color pigment, DesignWood, can be introduced during the treatment process to stain the wood in shades of brown.
Preserve CA-C treatment is also available with a built-in water repellent and marketed as Preserve® Plus.
Preserve CA and ACQ
Preserve CA - Copper Azole Type C (CA-C) is found readily across the US and Copper Azole Type B (CA-B) in Canada. Please watch our informative videos below to learn more.
The CA preservative formulation is made of 96.1 % soluble copper (100% recycled) and organic triazole co-biocides; tebuconazole and propiconazole, which help control copper-tolerant fungi. Preserve CA is widely used across the US and Canada.
Preserve ACQ - Alkaline Copper Quaternary (ACQ) is a water-based wood preservative formulation made of soluble copper and a quaternary compound. The soluble copper makes the wood very resistant to biological attack, and a quaternary ammonium compound (quat) acts as biocide and insecticide, increasing the tolerance of the treated lumber to copper-resistant bacteria and fungi. ACQ is used throughout the US, Canada, Europe, Japan and Australia.
Both Preserve CA and Preserve ACQ are seen as “greener” preservatives and a more sustainable option than previous wood preservatives. Both are also certified by Home Innovation Research Labs for points toward NGBS Green Certification to the ICC 700 National Green Building Standard.
Product Applications
Preserve CA and ACQ
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Above Ground Exposed Use
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Ground Contact General Use
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Fresh-water Immersion
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Salt-water Splash
The Qualities That Matter to You

Ideal for residential, commercial and certain agricultural projects in these applications:
- Above Ground Exposed Use
- Ground Contact General Use
- Fresh-water Immersion and Salt-water Splash

- Field-tested, proven-to-last, and accepted as an industry standard
- Building code compliant - IRC, IBC, and National Building Code of Canada (NBCC)
- American Wood Protection Association (AWPA) standardized wood preservatives
- Canadian Standards Association (CSA) approved
- Parks Canada approved
- Home Innovation NGBS Green Certified - Preserve CA and Preserve ACQ
- Formulated with 100% recycled copper
Preserve ACQ and Preserve CA treated wood are covered by a Lifetime Limited Warranty against damage from fungal decay or termite attack when installed in accordance with applicable building codes. See Preserve CA (US), Preserve CA (Canada), Preserve ACQ (US), Preserve ACQ (Canada) Lifetime Limited Warranties for terms and conditions.
Preserve ACQ and Preserve CA are NAHB Home Innovation Research Labs Green Certified Products for Resource Efficiency and are eligible to contribute points toward a buildings certification under the National Green Building Standard™ (NGBS). Preserve is also formulated with 100% recycled copper.
- Always use building-code approved, corrosion-resistant fasteners and connectors that are suitable for use in pressure-treated wood.
- Recommended Fasteners: use hot-dipped galvanized fasteners (meeting ASTM A 153) or stainless steel.
- Recommended Connectors: use G185 hot-dipped galvanized for exterior applications.
- For Permanent Wood Foundations and corrosive environments, such as Coastal areas with saltwater spray, use code approved stainless steel fasteners and connectors.
- Preserve is not suitable for direct contact with uncoated steel or aluminum building products.
Preserve ACQ and Preserve CA treated wood is covered by a Lifetime Limited Warranty against damage from fungal decay or termite attack when installed in accordance with applicable building codes. See Preserve ACQ and Preserve CA Lifetime Limited Warranties for terms and conditions.