Aluminum should not be used w/ACQ pressure treated lumber. The paper is a good thought, but the aluminum will still be in contact with the wood by the nails. The copper in the ACQ reacts with the aluminum. Dissimilar metal electrolysis.

True, but if dissimilar metals creates electrolysis then galvanized nails/bolts also should be avoided and I doubt they are. The presence of water is what really causes reaction. Plastic washers could be used as a dielectric but that too is probably overkill.

tool fool, look at the warning label on the PT lumber and see what they require. you might be surprised. Also, go to the simpson website and look into "Z" coatings

from http://www.safestronghome.com/resources/corrosion.asp

Pressure Treated Wood
The pressure-treated wood industry has transitioned away from the use of Chromated Copper Arsenate (CCA-C) to alternative preservative systems for residential use, effective 12/31/03. Some of the replacement alternatives are generally more corrosive than CCA-C. The corrosive content of treated wood may be variable. Over time, the durability and load-carrying capacity of Simpson products used with treated woods can vary widely depending on the many variables. This makes it impossible to predict accurately if, or when, significant corrosion of connectors, anchors, and fasteners will begin or reach a critical level. The treated wood industry specifies or recommends stainless steel and hotdip galvanized products for use with pressure treated wood. To select the appropriate connector for use with various pressure treated woods, see the Pressure Treated Wood Technical Bulletin.

Warning
While galvanized steel provides some protection, testing has shown that it is still likely to corrode if in contact with treated wood. The service life of galvanized parts depends on many variables including the location, installation, exposure, and the thickness of the galvanized coating.

Sigh....every time I think about them dumping cca it makes me remember how stupid the green mafia really is. J.

Remember all the elevated decks collapsing a few years ago? I think it was the summer of '06. It seemed to be in the media all the time. In many cases the cause was corroded metal connectors, due to the new ACQ lumber we started using a few years back.

The harsher the climate the faster the reaction.

Wood is full of water, and air, the 2 other things necessary for chemical reactions.

I won't be using galvanized anything but until someone invents dielectric bolts or figures out a way to make copper or aluminum more structural and affordable, dissimilar metals are a fact of life in building anything structural. An interesting fact is the vast majority of these failures appear back east where moisture is a constant. The only variable is cold or hot. Rain and humidity are ever present east of the Rockies. I'm in CA where year round moisture is not a factor. I'll use stainless bolts, I'll create "gaskets" out of building paper and I'll check on the brackets infrequently.