Strong Ties and pressure treated wood
It seems the pressure treated wood industry has undergone major changes. From CCA to what’s now CA-B, ACQ,DOT,ACZA, etc.
The anchor and connector people seem to say that the ordinary “run of the mill” joist hangers and connectors aren’t so well suited for these new pressure treatments. Except for DOT, the other treatments are apparently as much as 3 times more corrosive than CCA lumber on galvanized connectors.
Simpson has stepped up their products from “G60” to “G90” for use with CCA, but they seem to think it’s not enough for the new treated woods. They recommend hot dipped galvanized after manufacture (post hot dip galvanize) which they sell as G185 or “Zmax”. Better still, they recommend stainless steel.
What say you all? I’ve never even SEEN a stainless connector anywhere in use, and suspect it’s simply their way to reduce liability. Does anyone specify greater corrosion resistance connectors when using alternative treated woods? Or no connectors at all, and hand the “old fashioned way”???
Inquiring minds wanna know.
Replies
You must use highly corrosive resistant connectors with the new Pt wood. ACQ, the stuff available in my area, has a very high copper content, which causes galvanic corrosion in metal it touches. That's why stainless is the best way to go, though I haven't found any stainless connectors in my area yet. For flashing (ie on ledgers), use copper, which won't corrode with the new PT (for obvious reasons). Some grades of hot-dipped galvanized may not be adequate, so if you go that route, check with the manufacturer to see if it's acceptable to use with ACQ.
I've heard stories of nails and metal connectors failing within a year using ACQ PT lumber.
Andy
This is the only place I have seen SS hangers for sale so far:
http://store.yahoo.com/squaredrive/fasteners-concealed-deck-fastening-systems-stainless-steel-joist-hangers.html
Stainless Steel joist hangers are available in McFeely's catalog. http://www.mcfeelys.com
Gee, a 2x10 SS hanger is only $5.05. This can't possibly be the only solution to the new PT corrosion issue. Everyone I've talked to about it seems to say, "oh yeah, just switch over from galvy nails and hardware to SS". Anyone price out this stuff yet? Stainless steel gun spikes (3 1/4's) are $106.59 for a case of only 1000. Or how about lag bolts at $1.06 each. Now let's talk about flashing.....
Seriously, I consider this to be a pretty big PIA. I'll get beat out of every deck next summer by some idiot too ignorant to know he's using the wrong hardware and nails. Homeowner's aren't gonna know this stuff either. Gonna have to do alot of explaining.
Alright, maybe I'm over reacting, but there is going to have to be a pretty substantial adjustment regarding hardware, fasteners and flashing. I will feel compelled to explain this to my customers.
diesel... i know what you mean... ... but try to keep calm... look to Maze for HOT-DIPPED GALV..
and Simpson is selling their Z-max for not much more thatn their old standard hangersMike Smith Rhode Island : Design / Build / Repair / Restore
Yeah, the ZMAX looks to be the way to go. Basically a connector dipped after fabrication, the coating is G185, rather than G90 (some brands use G60!)
It looks like ACQ is the worst as far as corrosivity goes, it's 3 times more corrosive then CCA. So........The G185 is 3 times more corrosion resistant, and all things balance out.
Yes, it surely WILL be a consumer education period. How many don't even KNOW there's different kinds of pressure treatment (about 6 different processes), different retention levels (.10, .21, .40, .60,.80 all the way to 2.5 or something!) and different corrosion rates depending on chemistry...
There's a wealth of info out there, simpson strong tie's website is terrific, BTW.
Simpson offers some of their hangers in stainless steel:
http://www.strongtie.com/products/connectors_list/lus.html
"Some products available in stainless steel or Z-MAX..."
Or:
http://www.strongtie.com/ii_Coatings.html
"Connectors are manufactured from Type 316L stainless steel, and provide greater durability against corrosion than our standard connectors. Stainless steel nails should be used with stainless steel products, and are available from Simpson."You can never get ahead by getting even. [Japanese proverb]