Fastener and Connector Recommendations

MCA (Micronized Copper Azole) Treated Wood Products

While electro-plated fasteners are still not recommended, any hot-dip galvanize fasteners or connector plate (such as G-60) will give good service life with our MCA treated wood products. Other protected exterior fasteners allowed by building codes should perform well.

In addition, common steel fasteners may be used for UC1 and UC2 interior dry, weather-protected applications such as sill plates, interior framing and interior trusses. Since ProWood MCA (micronized copper azole) is less corrosive than ACQ and CA-C (see next section on CA-C), these recommendations are the same as they were with CCA-treated lumber. Fastener manufacturers may also recommend products that work well with ProWood.

Aluminum building products can be placed in direct contact with ProWood MCA treated wood products used for interior applications and above-ground exterior projects such as decks, fencing and gardens. Aluminum contact is not recommended when ProWood Professional Grade wood products are immersed in water or are subject to frequent and prolonged wetting or other severe exposure conditions. In such cases, a moisture resistant protective barrier should be placed between the aluminum products and ProWood.

CA-C (Copper Azole type C) Treated Wood Products

ProWood CA-C (Copper Azole type C) preserved wood is designed for long-term performance in outdoor applications and, therefore, requires high quality corrosion-resistant nails, screws, and other fasteners and hardware.

For interior and exterior applications, use fasteners and hardware that are in compliance with the manufacturer's recommendations and the building codes for their intended use. Where design and/or actual conditions allow for constant, repetitive, or long periods of wet conditions, only stainless steel fasteners should be used.

Fastener and hardware manufacturers have suggested the minimum hot-dip galvanized requirements for use with Copper Azole treated wood should conform to the following ASTM Standards: ASTM-A153 (for hot-dip fastener products) and ASTM- A 653 (Coating Designation G-185 for hot-dip connector and sheet products).

Stainless Steel - Stainless steel fasteners and connectors are required for permanent wood foundations below grade and are recommended for use with treated wood in other severe exterior applications such as swimming pools, salt-water exposure, etc. Type 304 and 316 are the recommended grades to use.

There may be additional products (other than stainless steel or hot-dip galvanized), which are suitable for use with ProWood CA-C treated wood. Please consult with the individual fastener or hardware manufacturer for recommendations for use of their products with ProWood CA-C treated wood.

Aluminum should not be used in direct contact with ProWood CA-C.

Spacer materials or other physical barriers are recommended to prevent direct contact between ProWood CA-C treated wood and aluminum products. When using ProWood CA-C preserved wood in close proximity to aluminum products, such as aluminum siding, flashing, furniture, and door and window frames, a 1/4" minimum space must be allowed for between the ProWood CA-C and the aluminum products. Polyethylene or nylon spacers can be used to maintain the 1/4" spacing. Another option is to use a polyethylene barrier, with a minimum thickness of 10 mils, between the ProWood CA-C preserved wood and the aluminum product to prevent direct contact of the wood and the aluminum.

ProWood FR (Fire Retardant) Treated Wood Products

Galvanized steel hardware is recommended for use with ProWood FR wood. Even though the ProWood FR treatment does not increase corrosion of bare or galvanized steel, galvanizing provides an added level of protection with any treated wood product. The following metal fasteners are compatible with ProWood FR wood and are outlined in ESR-4373: 2024-T3 aluminum, SAE 1010 steel, hot-dip zinc galvanized steel, copper, or red brass.