Tenino Copper Naphthenate 17% (2% Metal) Double Strength – 1 Gallon Wood Preservative

Tenino Copper Naphthenate 17% is a ready-to-use, oil-borne wood preservative for exterior wood. It's the Double Strength formula, containing 2% copper as metal, and it comes in a resealable one-gallon jug that needs no mixing or dilution. Brushed on, a gallon covers approximately 100–300 sq ft per application, depending on how absorbent the wood is.

The most common job for it is end cuts. When you cut, drill or notch pressure-treated lumber, the fresh wood inside is far less protected than the surface. Tenino meets the AWPA M4 standard for field application to end cuts in exterior use, so brushing it onto every cut on posts, beams and deck framing restores protection where it's weakest.

What it protects against

It repels water and resists termites, wood-destroying beetles and decay fungi. By slowing moisture movement, it helps reduce warping, swelling, shrinking and end checking. It can be used both preventively on new wood and as a remedial application on standing posts, poles and beams.

• Typical uses: poles, piling, fencing, siding, timbers, beams, cedar shakes and shingles, porches, docks, landscape timbers, planters and window boxes
• Low VOC: under 350 g/L
• Labelled for General Use
• Referenced standards: AWPA Use Category 4, 4B, 4C; IBC 2303.1.9; IRC R317.1.1

The copper is sourced from recycled copper and reclaimed by-products.

Good to know: copper naphthenate leaves a green tint on the wood, so test a hidden spot if appearance matters. It is for exterior use only. Read the label directions and safety precautions before applying, and follow local regulations for disposing of leftover product and offcuts.