201 On Treated Wood Fastening

[Nativespec]

Now that treated wood is safe for kids to consume, I have observed from the DIY channel that it is no longer safe for our old fastening ways. I have seen them put galvanized bolts through tubing to avoid contact with wood and use stainless fastners. Is there a more cost effective solution for nailguns and bolts?

Thanks,

David

 

[NCPete]

there are epoxy coated screws and fasteners appropriate for this new treated wood, but Stainless is the most resistant to the corrosive nature of the new preservative treatment.

 

[Nativespec]

I was planning on using a nail gun and I went to the Senco websit and they recommend the stainles, but the hot dip galv. is accepted in the industry by the treated wood manufacturers. The stainless nails are about .15 each where the hot dipped are .016 each. I cannot afford screws on this project. I wonder if decks will be falling down again some years from now.

David

 

[hannah01]

Evidently the new treated wood will eat through galvanized screws/bolts. How long it takes depends on the thickness of the coating. Here are a couple of links with good info:

http://www.strongtie.com/productuse/PTWoodFAQs.html

http://www.mcfeelys.com/tech/acq.aspx

Personally, I use stainless steel whenever possible, but cost-effective it isn't.

BTW, McFeeleys has their NoCoRode on sale.

 

[Nativespec]

thanks for your help

 

[Cuprousworks]

I don't know for a fact, but the rate of corrosion is probably also dependent on the amount of moisture.

When I was looking at both galvanized nails and screws for a construction project using a pressure-treated sole plate nearly all of the fasteners - galvanized and painted, screws and nails - noted that they were approved for all building materials. It's interesting that they would be in conflict with the materials manufacturer.

Mike

 

[Nativespec]

The Senco testing gave results of "red" and "white" corrosion/rust and I believe their testing was done under wet conditions. I am only building about 2 ft off the ground and the fall will be slow and not too far and my backyard only floods occaisionally (I live near Crabtree Creek).

I went ahead and bought hot dip nails from Amazon.

4,000 3" hot dip plastic strip nails for $65 delivered-not bad.

(1,000 stainless nails were $160 to $200)

Thanks,

David

 

[mkepke]

I noted this comment in the Simpson's link"

"At the time of installation my pressure-treated wood was installed dry (moisture content less than 19%) and it was installed in a condition where it will remain dry throughout its service life. What connector coating finish or material should I use?

Simpson's standard G90 galvanized connectors may be used with the following wood treatments: ACQ-C, ACQ-D (Carbonate), CBA-A, CA-B, SBX/DOT, and Zinc Borate if the wood was installed dry and will remain dry throughout its service life. If the chemical retention level in the treated wood exceeds the Ground Contact level then Stainless Steel connectors are recommended. (Ground Contact level is: 0.40 pcf for ACQ, 0.41 pcf for CBA-A, and .21 pcf for CA-B). Verify the actual retention level with the wood treater. SBX/DOT and Zinc Borate treated woods are less corrosive than CCA-C treated wood -- as a result the retention level of these woods is not of much concern and standard G90 galvanized connectors can be used. "

So it sounds like "regular" galvanized nails are recommeded only where the ACQ PT is not rated for ground contact, is installed dry and will remain dry. Which sounds like an area you probably wouldn't use PT anyways :eusa_thin

-Mark

 

[Nativespec]

I think what they mean is if it is a boat dock or other place where there is a constant wicking of moisture, then the wood will likely have a higher moisture content than say a residential deck. I think that This Old House, while very good and informative on technique, tends to overdo it at times.

David

 

[Cuprousworks]

"So it sounds like "regular" galvanized nails are recommeded only where the ACQ PT is not rated for ground contact, is installed dry and will remain dry. Which sounds like an area you probably wouldn't use PT anyways :eusa_thin"

Contact with concrete, as in the floor plate of a wall comes to mind. I sure as heck hope it is installed dry and remains dry!

Mike