mortar question

[George]

I'm replacing a lower roof, which abuts a cement-block wall. I need to flash this joint. In other places, I've cut a slit in the blocks, and fit the upper flashing into the slit. I can't do that here. Long story

- basically, there's an opening in the blocks that can't be filled with masonry. The opening can be covered, though.

I'm thinking to run a strip of wood along the wall at the joint. The upper edge of the wood could be tapered down for a smooth transition to the block surface. This would cover the opening, and the flashing would be attached to the wood. I would then need to seal from the block wall to the upper side of the wood and flashing. I plan to use mortar for this.

Questions:

1. What cement to use. I've read that acrylic-modified cement has considerably improved adhesion to wood/metal. Yes? If so, would something like Quickcrete Concrete Patch (contains vinyl) be a good choice? Or, would it be better to look for a stucco product? Or something else?

1. Should I use wire lath over the block-to-wood transition? I guess I could even nail the lath into the flashing, though that may be one of those things that works better in your mind's eye than in reality.

Thanks, G

[DanG]

George, I don't know if I really understand the problem. It sounds like installing a counter flashing higher on the wall would be the best solution rather than wood and concrete. Look up counter flashing, here is one good site that may give you some good ideas:

Look at detail 2 in the A drawing where they install the counterflashing in a sawn in reglet. There is another similar in drawing C.

Another option would be to use a surface counterflash like the first two shown here:

[RicodJour]

I'd lose the wood and go with proven products...assuming that you don't want to find out that your detail didn't _quite_ work.

These guys have been around forever and are big in commercial construction.

up a roofing supply house in your area and ask at the counter what product they stock and/or would recommend.

R