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#1 |
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Registered User
Trade: Remodeling
Join Date: Mar 2009
Posts: 3
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ACQ And Aluminum Corrosion
Has anyone experienced significant corrosion of aluminum against ACQ (2005) pressure treated 2 by's. I have an overhead awning/pergola with an L-shaped aluminum gutter that was fixed directly to a 2x8. The gutter is heavy-gauged (1/8" thick) aluminum and painted/powder coated - but it is directly against the 2x8. I just did not think of the potential damage at the time and it would be significant work to get it down and put a roofing membrane behind it. The application is well above ground and in direct sunlight all day. Is the talk of copper leaching from PT lumber overblown and more related to in ground or wet locations - or should i be concerned and consider adjusting situation before it is too late?
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#2 |
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General Contractor
Trade: New Home Construction-Additions-Remodeling
Join Date: May 2007
Location: NJ
Posts: 2,788
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Re: ACQ And Aluminum Corrosion
We have to know what area you from, so we can help you to figure the corrosion ratio for your area.
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I never lost a cent on the jobs I didn't get!
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#3 |
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always building
Trade: general constructiion
Join Date: Dec 2008
Location: North County San Diego Fallbrook CA
Posts: 618
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Re: ACQ And Aluminum Corrosion
i dont know how powder coated aluminum stands up against those chemicals but, they had no problem eating through hilti shot pins in 8 mos. it was this very situation that brought the whole industry dilemma to my attention. as far as you project being off of the ground, it is still subject to dew and rain no??? most people dont mind you fixing mistakes before they become a problem
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#4 |
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Mark
Trade: carpenter
Join Date: Apr 2009
Location: Franklinville, NJ
Posts: 163
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Re: ACQ And Aluminum Corrosion
I done a job about 2 years ago for a guy who had a pergula over the front door. it was not built by me but the other contractor built it out of all pt and wrapped the 6x6 columns with aluminium. No lie i sware 6 months later i got the call to look at it and the aluminium was bubbling like someone put acid on it. And they say the acq is supposed to be less hamfull........HMMMMMM
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" DO IT RIGHT THE FIRST TIME " |
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#5 |
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Registered User
Trade: Remodeling
Join Date: Mar 2009
Posts: 3
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Re: ACQ And Aluminum Corrosion
I am in the northwest suburbs of Philadelphia - and yes it is subject to dew / rain, etc - but very well ventilated and as mentioned sunny location. No visibile signs of corrosion, but definitely this is a high contact situation.
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#6 |
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Pro
Trade: Home repairs,drywall,trim.
Join Date: Jun 2008
Location: Florida
Posts: 978
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Re: ACQ And Aluminum Corrosion
My Z-Max post bases are corroding all to hell. That first wave of that new ACQ lumber a few years ago was some nasty a$$ stuff
. My ''exterior'' screws also coroded away and snapped in half.
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#7 |
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New Guy
Trade: remodeling
Join Date: Sep 2008
Location: Moneta, VA
Posts: 26
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Re: ACQ And Aluminum Corrosion
And this is what we use for bottom plates on wall framing.
Does everyone nail those with galvies now? |
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| The Following User Says Thank You to VAviaCo For This Useful Post: | parkers5150 (05-11-2009) |
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#8 | |
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Pro
Trade: GC Residential / Light Commercial
Join Date: May 2009
Location: Southwest Michigan
Posts: 133
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Re: ACQ And Aluminum CorrosionQuote:
I do! I use ACQ compatible fasteners wherever treated is used. I know many, many don't, and wonder how many garages will have sill plates that are no longer fastened to studs or sheathing after a few years.... "Sorry your garage walls fell off foundation, I guess I should've used specialty fasteners...." |
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#9 |
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Remodeling Professionals
Trade: Remodeling Contractor
Join Date: Dec 2007
Location: South Jersey Shore
Posts: 1,251
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Re: ACQ And Aluminum Corrosion
Most of the ACQ around here is being replaced with much less corrosive MCa treated wood. Nowhere near as corrosive to aluminum. Still have to use ACQ for ground contact though, unless you special order higher concentration MCa product.
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#10 |
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Pro
Trade: Home repairs,drywall,trim.
Join Date: Jun 2008
Location: Florida
Posts: 978
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Re: ACQ And Aluminum Corrosion
For interior work we use borate treated lumber for all bottom plates and concrete walls, no special fasteners needed. The big box stores don't carry it around here that I know of.
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#11 | |
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Curmudgeon
Trade: carpentry/remodeling/"Yes M'am we do"
Join Date: Apr 2006
Location: Beech Grove, Indiana, Birthplace of the "King of Cool"
Posts: 11,707
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Re: ACQ And Aluminum CorrosionQuote:
and it isn't a great choice for decks..... "Lumber treated with disodium octaborate tetrahydrate (DOT) historically has been used in protected, not exposed, locations because borate leaches from wood when the wood gets wet."
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Put your location in your profile! (Sorry....it seems there really are dumb questions) |
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#12 |
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Member
Trade: General Contractor
Join Date: Jun 2008
Posts: 59
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Re: ACQ And Aluminum Corrosion
It has everything to do with Galvanic Attack. Aluminum is less noble (anodic) than the copper in the acq (cathodic). It's too bad we can't use a sacrificial metal like they do with boats! I am curious how long it takes a stainless(cathodic) screw to cause problems with the copper(anodic) in the wood for the same reasoning.
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