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
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?
2. 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.
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
Look at detail 2 in the A drawing where they install the
counterflashing in a sawn in reglet. There is another similar in
Another option would be to use a surface counterflash like the
first two shown here:
Keep the whole world singing . . . .
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
Hit up a roofing supply house in your area and ask at the counter what
product they stock and/or would recommend.
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