To Ricodjove & tbasc: More On My Z Flashing Question, Please ?

[tbasc]

Bob, A complete answer would require knowing the wall construction behind the T1-11 plywood. Note that Rico and I * assumed * different construcions.

I don't think the flashing will protect the bottom edge of the plywood.

If the plywood rests on a flat surface - either wood trim or metal flashing - water will wick between the plywood and the flat surface below. Water in this condition is likely to wick into the exposed wood. On the other hand, if there is a bit of a gap, the water will have a chance to drop away from the plywood. Some water will penetrate the plywood and having a free bottom edge will allow gravity to do its work.

Now let's see what Rico thinks. TB

[RicodJour]

If a post is added to the thread it jumps to the top. Don't worry about it getting buried and don't start a new thread on the same topic. Use the existing one.

It keeps the end grain from sitting in a puddle of water that would sit on that horizontal leg of the flashing. It lets it dry out. It allows the painter to paint the endgrain. 'nuf said.

I think you're misreading that picture. Both Tom & I pointed out that the upper leg is BEHIND the siding. You don't see it. You do see the lower leg. There is no need top seal that top edge as it is behind the siding and the elements never reach it.

Look at the picture again. Better yet, do a Google for a T-1-11 and find the manufacturer's homepage. Check out their installation manual. It will tell you all you need to know.

R

[Robert11]

Hello all,

Will start a new post, as I guess my old one is pretty buried by now, and am hoping you guys will see it. Thanks so much for help and your time; really appreciate it.

Still very confused over how the Z flashing should be positioned to protect the bottom edge of vertical T1-11 siding that rests on, or close to, a horizontal trim board..

If there is a gap left on purpose between the bottom siding edge, and flashing, as was suggested in answers, doesn't this negate the flashing purpose as allowing the gap would (still) allow rain water to be wicked up into the end grain ?

Please see the Z flashing picture in:

This "seems" like a good way of doing it, except for sealing the top most flashing edge against the siding, as in my original posted question. I'll re-copy it for ref. below.

Hate to appear dumber than I really am with this, but this is a totally new area for me, and am trying to learn the principles, as well as wanting to have it done correctly.

Thanks again, Bob

---------------------------- Moved into a house that has T1-11 vertical siding.

At the bottom, the siding is "finished off" with a horizontal board that runs the width of the house. Typical pine board, perhaps 6" X 3/4 x ...

The bottom edges of some of the siding (rests on top of the 3/4 board edge) has wicked up water over the years, and looks as if I'll have to replace some of it. Also, a new horizontal board, as it does improve the looks.

It has been suggested that I make sure to have the bottom edge of the siding where it meets the horizontal board be flashed with a "Z Flashing". Certainly sounds like a good idea.

Found a picture of Z flashing on the web, and my question relates to the top most vertical edge of the flashing: Obviously there can't be a perfect seal here between the edge of the AL flashing and the face of the siding board.

When it rains, due to small gaps between, or just capillary action, I would imagine water seeps in and probably migrates to the bottom siding edge (again).

Is this anything to worry about ?

Is the paint that goes over all of this supposed to seal it adequately, or should one run a small bead of RTV here, or... ?

Any thoughts on all of this would be most appreciated.

BTW: T1-11 still used and available ?