Galvanized or not galvanized?? 1

[strucguy]

On one of the wood projects I am working on, the contractor is proposing to use Advance Guard borate treated lumber for sill plates, which he claims doesn't require anchor bolts be galvanized. It is our typical office practice to require galvanized anchor bolts where they are in contact with pressure treated lumber. Your views please. Thanks.

 

[woodman88]

Per the 2009 IBC Section 2304.9.5.1 "Exception: Plain carbon steel fasteners in SBX/DOT and zinc borate perservative-treated wood in an interior, dry environment shall be permitted."
You will have to check into whether the Advance Guard borate treatment meets this.

Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.

 

[strucguy]

Thanks for the prompt response, woodman88. I did check manufacturer's website, and they reiterate what's given in section 2304.9.5.1. But, as you already mentioned, uncoated bolts are permitted only in interior dry areas. Not sure if sill plates at the perimeter walls fall under this category.

 

[SLTA]

Going into concrete? You may want the anchor bolts to be galvanized anyway, depending on the diameter of the bolt.

 

[Ron]

Why would you not specify galvanized? The cost difference is minimal and it takes away a potential problem. Don't try to fine tune a building...

 

[strucguy]

We did specify galvanized. But, the contractor went ahead and installed regular anchor bolts. I already indicated contractor's stand in my earlier post. He is saying this is something they have done before. But, I am not convinced.

 

[focuseng]

Boron does not attack steel the way other preservative treatments do like CCA2 or whatever where it actively attacks steel. Boron is relatively inert while CCA is not. I think copper and arsenic are the culprits? However, the sill is susceptible to water/condensation/etc so rust is still an issue regardless of the the treatment or non at all -What slta and Ron said. The key part of woodman88 post is "interior" and "dry". Also, someone, somewhere will find a piece of Green treat wood and use it where they just need to fill in...

MAP

 

[Ron]

If you specified galvanize and the contractor installed plain steel, have him remove them and install what you specified.

Depending on the type of cladding you have on the walls, the plate and anchor bolts can be damp more than you'd like, so corrosion is an issue, without regard to the treatment method for the wood.

Tell the contractor he doesn't have to remove what's there, just go back in between and put the right ones in.

 

[strucguy]

Thank you all for the input. Ron...having the contractor install new galvanized anchors is definitely an option. But, there has to be an easy way out of this. How about having the contractor apply zinc-rich paint (it's typically used for touch-up and repair of galvanized members) to these plain bolts. Do you see any issues with that? Thank you.

 

[dicksewerrat]

He won't be able to paint the bolts inside the concrete. Tell him to get his drill and go to work.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[hokie66]

Black bolts are normally oily, so that would have to removed in order for a coating to have a chance. But I agree with Ron...bolts in external walls should be galvanized.

 

[Ron]

Agree with dicksewerrat and hokie66. Can't paint the unexposed bolts and you'll have oil on them as well. "The easy way out" is to have the contractor just install the specified bolts without taking the plain steel ones out. If you want to be a hard a$$, have him remove the incorrect ones.

I have investigated the failure of many exterior walls from water intrusion issues. Galvanized anchors are usually intact. Plain steel ones are often rusted away or nearly so.

 

[jdgengineer]

If this is residential I seem to remember the IRC has an exception to the requirement of galvanized bolts, but I could be wrong. I don't have it in front of me.

I agree with others, I have only used galvanized bolts in this situation.

 

[InDepth]

Have him give the savings of using carbon back to the owner.

 

[Ron]

InDepth....not good. The savings doesn't compare to the potential damage cost later on.

 

[Splitrings]

You specified galvanzied bolts...that is all that matters. Don't let the contractor off the hook. Maybe after epoxying new galvanzied bolts into the wall he'll pay closer attention to the specifications next time.