Flashing a cantilevered decl

[SurfLlama]

Hey Folks!

I"m about to do the sheathing on the front of my addition and part of the design is that there is a cantilevered deck at the front of the house. I want to make sure that where the deck joists come out of the house is flashed really well so that I don't have any water getting trapped anywhere and causing trouble.

I'm really not sure where to begin other then that I will obviously be using a Z-channel right where the deck floor boards will be.

Any guidance would be very welcome. I can take and post a picture if that is helpful.

Thanks,
Matt

[tooltroll]

Maybe something like this? Your siding would slip over and under the z flashing, and butt to the joist flashing. Make your joints good and snug, and use a good grade of caulking all around.

[Sweep]

To be safe use ice & water shield first, then metal flashing. Avoid aluminum flashing near pressure treated wood. Use heavy galvanized hardware in contact with pressure treated wood.

[ODDJOB]

Just wondered why to avoid the alum. flashing

[Sweep]

Aluminum and steel corrode rapidly when adjacent to or in contact with the new pressure treated lumber in the presence of water through electrolytic action because of the wood's high copper content. Since aluminum is the least noble of the flashing metals it will corrode more quickly than any other metal and should not be used. Steel should be separated from the wood or be heavily galvanized.
Aluminum should only be used when it can easily dry, and is not near or in contact with more noble metals or chemical treatments containing such metals. Aluminum is acceptable in those less corrosive conditions because in the open air it forms a thin film that protects it from further corrosion.

[ODDJOB]

Thanks 4 the info, Sweep. Is the high copper content a result of the pressure treating process ?

[Sweep]

Yes, the new law forces the manufacturers to reduce the arsenic and raise the copper content.

[ODDJOB]

Thanks, again

[Big Builder]

In addition to the flashing , ice and water shield and caulking we also block
the rim board out slightly to provide a patheway for any water penetration out. We just use 1 by fence boards ( PT) cut down right behind the lag bolts. Really helps to keep the rot away. ALso leave the
siding up a half inch or so to keep water from wicking up the siding. We bend our own flashing for the rim so we get at least six inches up the wall.