[Bob...]

6 months ago, I used some z flashing for the joint between T-111 siding and ChoiceDek composite decking trim, which I used to trim the bottom of a shed (gets the T-111 12" off the ground).

I notice that the flashing is already showing areas of white powder & pitting. The flashing is properly installed so as to not retain water.

Is this typical of all z flashing, or is there a better quality available? I bought the z flashing at lowes. It's pretty thin.

Thanks!

 

[mako1]

There are different grades and thicknesses from different manufacturers.The problem with yours seems to be the finish.I always used anodized from a quality manufacturer and purchased at a lumber yard not a BB store.

 

[Windows on Wash]

Is it aluminum? Is it up against PT lumber?

 

[Bob...]

Thanks mako1. That gives me direction. Windows on Wash: Not sure on aluminum. Top vertical flange under T-111 backed with PT studs and PT on flat in cavity.

 

[joecaption]

Aluminum or even steel flashing should never have been in direct contact with PT wood.
The copper it's treated with will corrode it in no time.

 

[Bob...]

Aluminum or even steel flashing should never have been in direct contact with PT wood.
The copper it's treated with will corrode it in no time.

Can you recommend what should be used? Deep south climate - Thanks.

 

[Windows on Wash]

Vinyl is probably to most durable. They make vinyl coil stock that is workable in a trim brake.

 

[mako1]

Aluminum or even steel flashing should never have been in direct contact with PT wood.
The copper it's treated with will corrode it in no time.

Joe is correct.I was not thinking about the PT aspect when answering your question.
I live in farm country and we build lots of pole barns that have z along the pt boards at the ground level .The Z we use on them holds up for many years without issue.They are painted/coated with some sort of a ceramic paint that does not react to the PT wood .I think even HD sells some pole barn metal these days so you may try that.They have the Z and some other trim pieces in limited colors and quantities.

 

[Bob...]

Thanks mako1, Joe & Windows. I appreciate your help. I'll check to see which material is available here.

Again, thanks much.

 

[ChuckF.]

You can also use peel and stick-on rubber flashing on the Z-flashing to isolate it from the treated wood.

 

[Bob...]

Thanks for your suggestion, Chuck.

Also, just wanted to post back. Since I haven't been able to find the coated stock around here. The vinyl suggested by WoW is viable, but I've also been told that copper flashing would work. I don't need that much, so expense shouldn't be an issue. Also, I have easy access to sheet metal shops via my business.

Any reason not to use copper?

 

[Bob...]

Now for the final question: Since I have to give the measurements I want the flashing cut & bent to, What are the recommended tolerances? I really don't want to use the same measurements as the Lowes z flashing, as I thought it was a bit undersized.

From the diagram below, what dimensions should the flashing be cut to?

Also, I believe they cut from a 10' sheet. The long side of the shed is 10' 1 1/2", but I plan on using MiraTec trim at the corners. Can I assume that a 3/4" shortfall at each corner won't be an issue under the trim?

Apologies if the questions seem a bit anal, but I'd rather not do this again. Thanks!