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We have been requested to build an addition onto an existing house using treated wood for all of the framing. The owner has requested that all of the work last at least one hundred years like the original house did, and he has asked about reactions between the metals in the fasteners(nails, bolts, hangers, etc.) and the metals used in treating the wood. We know that this is an issue when doing metal work.
Since the metals present in the treated wood can vary are there types that we should avoid. Has anyone run into problems with corroded fasteners due to the wood treatment?
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Don, our local code for residential construction(CABO Section 322.3) requires that only hot dipped galvanized, stainless steel, silicone bronze or copper fasteners be used with pressure treated lumber, with the exception of 1/2" and larger steel bolts.
Anyone who has demo'd an old pressure-treated deck can attest to the corrosion evident on standard electro-galvanized nails or common sinkers.
We're using more and more stainless steel screws, but have also had excellent luck with Maze PTL decking nails. All our bolts, including the 1/2" size are hot-dipped.
Make sure your joist hangars are hot dipped galvanized, too, along with the hanger nails.
Compliantly, Steve
*Also, Don, could you delete your other post with no text?Only you can do it.Steve
*But the corrosion of fasteners on a deck is caused by the elements, not the wood, no? I don't remember pt having acid/alkaline or galvanic properties.Pressure-treated lumber is so wet and ill-behaved, I would not want to use it inside -- which the industry discourages anyway ... shrinkage/warpage/etc. will be terrible in the dry confines of the house, supposing the stuff manages to dry out sealed in walls in the first place ... and what a pain to cut and nail all that dense wood ... ask your customer why he needs pt if the old untreated framing did fine? He may have the wrong idea about the stuff.
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CCA [chromated copper arsenate] is indeed corrosive. Since it's properties include metal I wonder if it is electrolysis that occurs between the treatment and the fastners? Hot dipped galvanized is the way to go unless you can budget in stainless steel. I would sure try to use lumber kiln dried after treatment.
Scott
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CCA, ACZA treated wood is considerably more acidic than most framing materials (unless you are using green oak or western red cedar). Also remember that the treating process reduces the strength of the lumber and that code requirements still have to be met. You might want to pass this by the building inspectors for stud sizes and spacing, and for header sizing as well.
This definintely requires hot dipped or stainless nails. Since I don't think that hot dipped are available for nailers, I would definitely go with stainless. Those might be available special order for nailers. If you have to hand nail (ugh) I would insist that the homeowner pay the extra for the stainless steel nails, and save your arms. I am only a furniture/interior woodwork type guy and not a carpenter so the hot dip nails always take me a few more whacks to drive home. A couple of extra whacks times how many nails and your talking about real time and labor! Especially as it relates to sheathing -- I cannot imagine anybody actually hand nailing plywood anymore.
In Orygun framing is almost always done with wet lumber. Get it together and get it up and get the sheathing on. Then hope for some dry weather for it to dry before rocking.
*Steve:I'm new to this site. How do I delete my no text posting?Also, thanks for the info.Thanks,Don
*No big deal. Go to your other post, and see if there is a "delete" button. Click on it, and away you go. This may not work if you do not sign in with a password, or have not registered your preferences.BTW, I agree with others that I wouldn't try to frame with standard treated lumber. The stuff is too wet, and will twist, etc. as the framework dries out. The new construction will last a hundred years if you sweat the details of flashing, siding, etc. and build on a solid foundation.Best of luck, Steve
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We have been requested to build an addition onto an existing house using treated wood for all of the framing. The owner has requested that all of the work last at least one hundred years like the original house did, and he has asked about reactions between the metals in the fasteners(nails, bolts, hangers, etc.) and the metals used in treating the wood. We know that this is an issue when doing metal work.
Since the metals present in the treated wood can vary are there types that we should avoid. Has anyone run into problems with corroded fasteners due to the wood treatment?