Sealing a frame stucco over ICF basement
所以我有一个地下室ICF罢工(大多数of which is well above grade) with a 2×6 frame stucco floor above that. The stucco will cover the whole structure. Here’s a detail on the transition (https://i.imgur.com/sLvZSN4.png)
So I had planned on a sill gasket (e.g. Conservation technology) above the ICF but I’m a bit concerned about the best way to seal up the rest, especially with the ICF-Frame transition. Typical frame stucco would have a simple tyvek wrap over the sheathing and then probably a z-flashing to transition to the ICF. I’m planning on at least replacing the tyvek with a self-adhered WRB, but the transition to the ICF is giving me pause.
Any thoughts for a good way to wrap/seal this?
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Hi Rszimm.
窗台下的垫片提供了必要的生产技术llary break so the sill doesn't take on moisture wicking up through the concrete it is sitting on. You should include that regardless of your other air sealing and water management details.
Z flashing would be used to direct water out from behind the foam on the framed walls to the surface of the ICFs, but since it seems like the foam installed over the framed walls will be installed directly to the sheathing, I'm not sure that makes sense. If you go with a self-adhering WRB over the rigid foam on the framed walls, can't you lap it onto the ICFs to cover the seam between them? That would give you and air and water seal there.
You know, I've been debating about putting the WRB on the outside of the foam. It's just not how it's generally done. Usually the order on a standard 1-coat stucco system over frame is:
1. Framing
2. sheathing
3. WRB
4. 1" rigid foam
5. Lathe
6. stucco base coat
7. stucco finish coat.
So the Z-flashing would go behind the WRB on the top (where the framing is), and come over the front of the ICF.
I'm leaning toward a Vicor env-S system mainly because it claims it seals around any nails/screws that go through it, and there are a zillion of them with the lathe being secured to the OSB. The Vicor spec sheet doesn't state that it sticks to rigid foam, so I'd be a bit concerned about trying to stick it at that layer.
So, even with the vicor I've got a gap in my air barrier where the framing meets the ICF. The sill will get sealed with the gasket. I'm thinking about bedding that Z-flashing in a bunch of liquid flashing to seal it up. Or maybe I seal that gap by putting a bead of caulk under the bottom edge of the sheathing as it's getting attached to the framing. Hmmmm....