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Cultured Stone Flashing Details

6874 Views 4 Replies 2 Participants Last post by  Tom Struble

I will be installing cultured stone on the front of my house. I had some stone cap flashing bent up on a brake- 1.25" leg with a hem, and about a 3" vertical leg.

The stone will come right up to the bottom of two windows, and the third window has a 4.5" piece of trim under it. How far do I carry the stone ledge flashing around the windows? Should it go under the siding and vertical trim, butting right up to the window case? (Andersen 400 series). Or, should it go under the siding, and stop where it meets the window trim (3.5" wide trim)?

The particular area I am concerned with is in the window nailing flange area. Should I remove the bottom nails on each side and slip this flashing up under the nailing fin and membrane? The whole window rough opening was wrapped in Tyvek and then self adhering membrane flashing, so I am hesitant to cut into this waterproof plane to install the flashing, which is why I had thought to stop it where it meets the vertical trim.

Hope this makes sense- would appreciate any advice.
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OK- I realize the description was probably a little hard to follow, so I put some effort into it and took a couple pictures. Maybe that will help spur some comments.

I will be putting a double layer of felt up under the Tyvek approximately 6 inches up from the top of the stone, per the manufacturer's drawing. The metal flashing will then be installed with the Tyvek lapped over the vertical leg.

In picture 1, you can see a red outline that would represent the flashing- 3" vertical leg and 1.25" horizontal leg to go out over the stone cap. The way I have shown it, the flashing would go all the way to the window edge, but in order to allow water to flow down the window and out, I'd have to cut that ProtectoWrap and Tyvek at the blue line and slide the flashing underneath it. Does this seem OK? The flashing would still sit on top of the nailing flange. I worry about any water that comes down the side of the window getting behind the flashing right at the edge of the window case.

In picture 2, I had thought about cutting the vertical leg at an angle away from the window. This would allow more of the ProtectoWrap to stick to the nailing fin, which I think would seal better. Perhaps I'm just overthinking this, but I want to ensure I don't have to worry about leaks.

Finally, the stone (Eldorado Stone) will come up to within 3/8" of the bottom of the window, per their installation detail. They recommend a bead of sealant between the bottom of the window to the stone. Seems like this would trap water if it got in there, but it is per their CAD drawings... any thoughts on that?

Thanks in advance!
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you are not over thinking this,what you need to remember is that all that nice window sill flashing you did needs to divert the water to the outside,not just under the stone

i would have detailed the flashing to go under the sill membrane and add a piece of trim to the bottom of the window
Tom, thanks for the reply. It's not too late to change my plans...

I could run a piece of 3.5" trim under the window and drop the stone cap down below that trim in the window areas. This would let me properly flash the sill membrane so that it diverts water out over the cap, and in hindsight, sounds like a much better plan.

In the installation detail drawings, I wasn't real comfortable with the fact that any water that ended up on the bottom of the window (and on top of sill membrane flashing) would only be directed behind the stone, but this is what they show. In the case of veneer stone set into a scratch coat, it doesn't seem like there will be any drainage back there at all, even though they call for weep screed on the bottom of the assembly.

My other thought is to install a drainage plane of some sort behind the stone, either by furring or using a fluted plastic product. So many decisions... fortunately this area is well protected by a 4' deep portico, but I don't want to do it any differently than if it was completely exposed.
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enchanced drainage is always a good idea:thumbsup:
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