The #1 approace is my choice by wide margin. You might find the z was nailed to sheathing before upper T-1 was installed or it might have 1 or 2 nails to hold it until T-1 could be installed.

#2 I don't have any thoughts on.

#3 I don't believe you can buy enough caulk to replace flashing. And if you try it's a mess to remove later when it has to be done right. If you can work a new piece of metal(not nessarly z ) under upper siding and overhanging old z,that's a satisfactory repair until you can do it right.

Try primed flashing. It's heaver than big box galvinized stuff. I reused a few pieces of roof drip edge on a detached garage a few years ago and the new rusted worse than the old so that tells me all is not the same quility.

"That shouldn't take that much caulk, and caulk is cheap compared to residing"

In my experience,that line of reasoning ultimatly leads to not only rotted siding but framing as well. I understand #3 and I'm telling you that installing trim in a bed of caulk will leak. I have seen the result several times plus I tried it above a couple of portable building doors and it doesn't work.

If you think any kind of caulk is going to keep water out in that spot, think again. You are making a sandwich with moisture for the filling, and the bread will be soggy!
Casey

Well, I was talking about simply using a visible bead of caulk along the top joint, no sandwich or bed involved. However, I'm considering your input, that it's from two people certainly carries more weight. I have had good experiences with using caulk appropriately (until it fails, when you replace it *smile*), and I do agree, overusing it isn't productive.

Thanks for replying, I appreciate it.

My final solution was to replace the siding that had the rusted z-flashing before getting the house painted about 3 years ago. So the new siding was put on and started it's life with a new coat of primer and paint. Still looks great after almost 3 years. I have hopes that the rust won't recur. I don't know if the rust was characteristic of T1-11 siding over time, or if it was a result of neglect by previous owners. If it was caused by neglect, I don't plan to let that happen again *smile*.

Thank you for the update and glad to hear it turned out well. The T1-11 has nothing to do with how flashing rusted. Hopfully you used factory painted flashing or painted the flashing,if not,paint it now. While we are on the subject,I have additional suggestions. New galvanized metal usually has an oily film on it that resist's paint. It's recommended to wipe oil off with thinner before painting or alow metal to weather for 6 months or longer before painting. If you find yourself with siding in good condition but rusted flashing,the rust can be treated then painted. Any good paint store offer's rust converter that is brushed on,primed then painted. My favorite is Jasco brand. It's water thin and 1 quart easily cover's 200 square feet.

Thanks for the advice. I didn't say it, but meant to imply that the flashing was painted when the house was painted. The painters knew to wash the oil off the flashing before painting immediately after installing.

I did have rusted flashing with siding in good condition, and tried rust converters, various other things that were supposed to work, whatever I could find that might work, but the flashing would show rust after priming and painting sometime in the following winter (rainy season around here). So it goes, just hoping for no repeat of that. A lot of work for no result.

Going to keep it painted and hope for the best.

I have rotted t1-11 on my shed. I have bought new siding t1-11 5/8 and sawed the bottom 4 ft of the old siding to repair the whole side of the shelf. My problem now is how to install the Z channel. Can I bend the the bottom of the old siding up and simply put the 2 inches of flashing behind the old siding and then push the new siding up to the Z channel, caulk the top of the new siding, and then attach the new siding to the sheathing (Studs)? Tks 4 Help,,

Tom Thompson JustTom@cox.net 850-501-5582

The answer is yes to everything you said except do not use caulk anywhere on the Z flashing. The tool you need to pull siding up enough to slip flashing under it is a"wonder bar". One tip I will offer is to paint bottom cut edge of siding before installing Z.

I really appreciate the answers to my questions. Being a total novice at projects such as this, I needed the confidence you imparted that I was on the right track and that helped a great deal. Thank you....