I’ve never worked with ACQ treated lumber before and after seeing a piece of coilstock misapplied to a treated timber, I have some misgivings. I planned on applying 16″ aluminum flashing that would extend above and below my ledger (2×10). Over this would be a layer of butyl membrane that is self sealing. The ledger would go against this and be attached using hot dipped Galvie lags. I like this Idea because it isolated the treated from the flashing and I ended up with one board that is still CCA so I plan on it being the ledger. My concern is how to apply a right angle flashing on top of the ledger and up the wall that would be compatable with acq decking.
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The way our company does ledgers is to put snow and ice shield on the backside of the board then nail double dipped galvanized flashing to the bottom of the board. We then secure it to the building and apply another flashing on the top and nail it off to the wall so the siding will cover it. As long as you stay with dd galvanized products, that's supposed to be enough. Mixing aluminum with acq and throwing in some galvanized lags might create some corrosion from the dielectric interactions of the disparate metals. We do mostly through bolting when feasible and only on high end decks do we use stainless steel anchors. Others will chime in on this since the jury's still out on how long it will be before today's standards are yesterday's mistakes with acq.
OK, I'll swap the alum for gal flashing. I was concerned around here I wasn't finding double dipped flashing. I'll do some more research. Thanks
There is a technical bulletin out from Simpson (t-ptbarrier04 9/04 exp.6/05) that all their hangers and brackets should be separated from ACQ by applying Grace Vycor deck protector (http://www.graceconstruction.com) self adhered flashing between all there products to alleviate the corrosiveness of the wood.
In other words you may want to add a few more hours to your proposal for all this safe guarding.
"Rather be a hammer than a nail"
Bob
I use the ice and water shield, but I use copper flashing instead of aluminum or galvanized. My lags and through bolts are stainless. Why fool with such an important area? Working from the rim joist out, I put ice and water shield over everything and under the siding, then 12 or 16 inch copper under the siding and over the water shield, then I install half inch treated plywood spacers cut with a point on top, then I through bolt and/or lag the ledger through the spacers. This leaves a gap for drainage and eliminates the need for step flashing.
J Painter