I read the article in the recent Fine Homebuilding issue about isolating the joist hangers from the ACQ lumber with peel and stick flashing. The joist hangers available(Simpson) in my area(Florida) are rated ASTM A153, which I believe is a minimum galvanized coating for use with treated lumber. But what does that mean? Will the deck be unsafe in a certain number of years if the joist hangers come in direct contact with the wood? Same goes with the hot-dipped galvanized nails I’ve used in the past for decks; are they obsolete now? Will they corrode away in a few years? Why do they still sell the nails if stainless steel or coated screws are recommended? Any info would be appreciated. Stephen
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I can't answer the 'why do they sell treated lumber but not treated hardware' riddle. It's stumped me for years.
But, yea, whatever you get, check that it is rated for ACQ. Most hardware has a sticker/starburst on the packaging that states that. I think it's either triple-dipped or stainless.
And yea, if it's just galvanized, it very well might start corroding soon.
Edited 7/28/2008 10:39 pm ET by darrel
o my im glad i read this, im building a deck and end nailed 16pennys , i forgot that gal nails corrode, i can still toe nail ss but will check with the lumberyard.
We have been using MCQ (Micronized Copper Quaternary) Same corrosive properties as ACQ. You still nedd to use the same precautions.http://www.greatsouthernwood.com/products/product.aspx?id=17 Chuck Slive, work, build, ...better with wood
>>Same corrosive properties as ACQ.<<
Not really the same.
From the link you provided - I added the red highlighting:
>>Fastener Information YellaWood¯ brand pressure treated pine with MCQ preservatives exhibits corrosion rates on metal products similar to CCA pressure treated wood and untreated wood. [.........]
MCQ Snapshot Treatment Type: Micronized Copper Quaternary
Protection from rot, fungal decay and termite attack: Yes
Fence Warranty: Limited 15 Year
Above Ground Warranty: Lifetime Residential & Agricultural Limited
Ground Contact/Fresh Water Contact Warranty: Lifetime Residential & Agricultural Limited
Paintable/Stainable: Yes
Color Pigments: a cedar tone for a look similar to cedar products or a brown tone for a look similar to redwood products
ICC/NER: #628
EPA Approval: Yes
Building Code Compliant: Yes
Corrosion Characteristics: Similar to CCA treated and untreated wood
Aluminum Contact: Yes <<
MCQ is considerably less corrosive than ACQ.
Following the ACQ guidelines for fasteners / hangers etc. certainly will not hurt.
Jim
Never underestimate the value of a sharp pencil or good light.
Jim,
Maybe I am reading it wrong.Further on down they state:
"... Use fasteners and other hardware that are in compliance with building codes for the intended use with ACQ treated products. To prevent premature corrosion and failure, consult the end tag to determine which preservative or preservative treatment was used and follow the metal products manufacturers' recommendations (including Fastener Information Sheets) as they relate to the specific preservative or preservative system indicated on the end tag. contact with such products. Use fasteners and other hardware that are in compliance with building codes for the intended use with ACQ treated products. To prevent premature corrosion and failure, consult the end tag to determine which preservative or preservative treatment was used and follow the metal products manufacturers' recommendations (including Fastener Information Sheets) as they relate to the specific preservative or preservative system indicated on the end tag..."
When I used it this spring, I used HDG ring shanks rated for ACQ. (Probably because I had them.
Chuck S
Edit: I did read it wrong. You are right. (I misquoted my own link ;-) )
live, work, build, ...better with wood
Edited 7/29/2008 10:56 am ET by stevent1
Back in the old days we used CCA treated wood, hot dipped galvanized nails, thinly galvanized hangers and aluminum flashing for decks and such. Further, we used plain steel foundation bolts with CCA sill plates.
At some point the media figured out that the "A" in CCA stood for arsenic and general panic arose. CCA got banned (for general use) with a phase-out period.
ACQ treatment was the first answer. With it came accelerated metal corrosion issues. Manufacturers such as Simpson scrambled to solve the corrosion issues.
There was a period where the old style (thin) galvanized hangers were still being sold and erroneously used with the new ACQ lumber. Some builders were not up to speed on ACQ, used the old hangers and had problems. Likewise they flashed and or wrapped ACQ treated wood with aluminum and watched it corrode from the inside out.
Now it seems the old hanger stock is gone, replaced by prominent warnings and ACQ approval stamps, the fastener manufacturers have changed their zinc coatings and all is well.
Along came MCQ - the second generation of non-arsenic treatments -- last September was the first I saw here marketed under the name of "ProWood" by UFPI. I have a corrosion test still in progress comparing 10 different fasteners plus aluminum flashing in ACQ, MCQ and kiln dried.
You will not be unhappy with the performance of ACQ rated HDG nails. In fact, you would probably be hard pressed at present to find HDG nails which were NOT rated for ACQ use.
Jim Never underestimate the value of a sharp pencil or good light.
Jim,
I remember using CCA lumber back in the 70's that was KDAT. Some of it was good.
When ACQ came out in late 03 and by law in 2004( I think). We had to scramble to find SS anchor bolts, washers and nuts for the ACQ mud sills.
Who are you doing the corrsion test for?
The reason I ask is someone posted some pics a while back of joist hangers that were in contact with ACQ and they were about corroded through. I imagine there have been or will be major deck failures on tract homes and townhouses built in 04 that were not properly built.
Chuck S.live, work, build, ...better with wood
>>Who are you doing the corrsion test for?<<
Just for my own information - it all started with a thread here which was called "ACQ vs nail" about a year ago.
My interest was piqued when my neighbor had a screened in porch built - ACQ posts which were wrapped with aluminum coil stock - about a year later the contractor came back, removed the screens, ripped off what remained of the aluminum coil (was not very hard since they had used aluminum trim nails).
Then rewrapped the posts with vinyl and SS trim nails.
I don't do much PT work, but was aware of the issues. I have been using SS fasteners with ACQ, $$.
I am afraid it is more like a "real wold" test rather than a closely monitored more scientific test.
I drove 3 each of 10 fasteners into ACQ, MCQ and kiln dried (control). Two sample boards were made on the same day.
One set of samples has been left outside (southeast exposure).
The other set was left outside for about 10 days - then moved to my basement to simulate floor joist to mudsill installations.
Should pull the first row soon - the bright nails look pretty bad on the outdoor test boards - of course I expected that!
JimNever underestimate the value of a sharp pencil or good light.
Thanks for your feedback. It seems like I can't give the homeowner a time limit in number of years for h.d. galvanized fasteners and joist hangers, just to say that stainless and coated screws are closer to the ideal; and that isolating all the hangers from the p.t. wood incrreases longevity
Any Simpson product marked Zmax should be rated for ACQ.