Connect Post to Footer with ACQ lumber

susanrk · 01-06-2011, 11:57 AM

I am wanting to know what to use to connect a footer to post and post to beam on a deck when using ACQ (chemical used in the wood) pressure treated lumber. The company does not have a specification sheet. I am concerned that galvanized nails and galvanized strap on this severe weather pressure treated ACQ lumber will corrode. I am wanting to know if stainless steel, while not as strong, will work and if stainless steel straps are available?
Thanks

MBatson · 01-06-2011, 04:50 PM

http://www.southernpine.com/pt07_use...asteners.shtml

Ex cert from the page:

Quote:

Copper-Based Preservatives

Copper-based formulations may be used in interior or exterior applications and include the traditional Chromated Copper Arsenate (CCA) and advanced products such as Copper Azole (CA) or Copper Quat (ACQ or Micronized Copper). CA and ACQ have shown a slight increase in corrosion rates on mild steel compared to CCA and Micronized Copper.

In damp or wet environments hot-dip galvanized or stainless steel hardware is strongly recommended in contact with copper-based preservative treated wood. Hot-dip galvanized fasteners should meet ASTM A153. Hot-dip galvanized connectors should meet ASTM A653, Class G185 sheet with 1.85 ounces of zinc coating per square foot minimum.

Type 304 or 316 stainless steel is recommended for maximum corrosion resistance in more severe exterior applications, such as swimming pools or within five miles of salt-water. Stainless steel fasteners are generally required for below-grade applications such as Permanent Wood Foundations. Stainless steel is also a recommended option when CA or Copper Quat formulations are specified at retention levels greater than required for Ground Contact.

Standard carbon-steel, aluminum, or electroplated products must not be installed in direct contact with CA or ACQ treated wood. However, aluminum products may be placed in direct contact with Micronized Copper treated wood when used in interior applications, or exterior applications above ground.1 Electroplated galvanized metal products generally have a thinner layer of protection compared to hot-dip galvanized and are typically not accepted by the building codes for use in exterior applications. Fasteners and connectors used together must be of the same metallic composition to avoid galvanic corrosion (e.g. use hot-dip nails with hot-dip joist hangers).

When aluminum or electroplated hardware must be used in proximity to CA or ACQ treated wood, spacers or physical barriers can protect products such as flashing or termite shields. Barriers should be non-conductive and remain durable for the intended service life of the application. Suitable barriers may include heavy plastic sheeting, rubber, vinyl, or a high quality, non-permeable tar bitumen or epoxy.

Hardware coated with proprietary anti-corrosion technologies is also available. Consult individual hardware manufacturers for specifics regarding their performance.

susanrk · 01-06-2011, 07:37 PM

Thank you for your comments.

I have attempted for 1 week to get the specification sheet from manufacturerer and no one can provide.

One more question. On Lowes, I found that their lumber shows under this url
http://www.lowes.com/pd_201676-432-S...718+4294965820

under description for Severe Weather 5/4 x 6 x 8 Premium Treated Decking that
Hot dipped galvanized or stainless steel fasteners and fittings are acceptable for use with ACQ treated wood
I can not find this written on other severe weather premium treated materials whether a post or beam... Can this be applied to post and beam that are premium treated with ACQ as well? Or does that item need to also show and state this to know that I can use galvanized steel as well.

Also in the article you provided, it appears for below ground (footings with fastner to post) that stainless steel is recommended. Yet where can one get the stainless steel straps ; only galvanized are easily found. There is a marine store that offers them (costly) and they say to use a nail and not a screw and I would think a screw is better into wood.
Thoughts?

Thanks for your help.

Susan