B-27 2020-Current: Timber Connectors and Fasteners for Use with Pressure-Treated Wood

Pressure Preservative-Treated Wood and Fire-Retardant Treated Wood can be caustic to zinc coated (or galvanized) steel and cause the metal to deteriorate.

Connectors and fasteners utilized with these wood products must be of the correct type. Fasteners of compatible material should be used to install connectors. This requirement does not apply to the typical installation of foundation, hold down bolts, anchor bolts, plate washers, straps, etc. when installed above grade and not exposed to the weather.

Version: 04/01/2020
Revised: 12/31/2007
Effective date: 09/01/2001

All metal connectors in contact with pressure-treated wood should be either hot-dipped galvanized or stainless steel. Galvanized connectors should not be placed in contact with treated wood unless the wood is adequately verified to be suitable for such contact. Some wood treatments may not accelerate metal deterioration. See the wood supplier for specific recommendations.

Fasteners of comparable materials should be used to install metal connectors. Fasteners must be hot-dipped zinc coated galvanized, stainless steel, silicon bronze or copper. Electrogalvanized nails, screws or staples shall not be used.

When preservative treated wood is cut or drilled after treatment, the cut surface shall be field treated with the appropriate preservative.

Contact the preservative or connector manufacturer for their specific recommendations regarding fasteners.

Note: In all cases, fasteners must be hot-dipped zinc coated galvanized, stainless steel, silicon bronze or copper. Electrogalvanized nails or staples shall not be used.

• California Residential Code R317
• Sonoma County Residential Construction Handbook, Sections 8, 18.7
• Western Wood Preservative Institute