NSR - Stucco around replacement window

Web searches have been strangely un-fruitful. Maybe I'm using the wrong terms or something.

Anyway, I recently put in several large egress windows in a basement. Removed original window, cut out foundation to fit new window, put in new (new construction) window in PT box secured to new, larger opening.

So, now I'm trying to figure out what is the correct (best) way to seal up the window around the PT box. The foundation of the house has a troweled finish, nothing fancy, so the appearance piece of it should be fairly simple. My question is, what's the right way to seal up the gaps between the window/PT box/cinder block. I would think I need flashing on top of the nailing fin (which is caulked already), I've seen some flashing "tape" that has an foil top w/ a tar-like backing that really sticks to the window/wood. But then you have a super-slippery surface that makes getting the mortar/stucco mix nearly impossible. Do I need to put another tape on top of this, like a fiberglass mesh or something, and then get to work with the mortar?

Somebody, help!

That description made my head spin...can you post a picture?

Ideally, you would get some sort of product (tarpaper is usually easier than flashing tape) up behind the existing stucco and bring it over the top of the nailing flange on the window. Flashing tape to the sides would be a good idea, too. For final finish, you will need to attach some metal lath (chicken wire in some areas, or expanded metal in others) to the concrete. That is what the mud will stick to.

I would probably be tempted to trim it with cedar or a composite instead of trying to match a troweled finish.

yeah, I agree, a pic would help. Can't say for sure, but by the description this is my suggestion.

Is the stuff you want to put in Bituathene (Self Adhering Sheet Membrane)? That's the one side sticky, other side shiny stuff. Typically, it's used as window flashing and installed around the opening before the installation of the window. If so, you need to prime it before you put any lath and plaster over it. That, and put a piece of plaster trim at the intersection of where the new stucco will intersect the window. This gives you something to trowel to.

If you are going right over concrete or block, make sure you prime the concrete so the stucco will stick to it. Again, put in a piece of plaster trim.

Is this 1/2'' or 7/8'' stucco?

Again, a pic would help.


Edit: What's a PT box?