I have an exterior stucco wall that's not in super great condition. The outermost-layer was applied very badly and is flaking off, so doing a patch job or yet another layer seems like a bad idea because the layer it would be adhering to is itself not adhering well. As part of this project, I will be adding rigid foam insulation to the exterior side of the wall. My question is this: can I reasonably screw-and-glue the rigid panels right over the existing stucco cladding, or should I really remove all the prior layers of stucco first and attach the foam directly to the wall sheathing? Advantages and disadvantages to each?
Adding insulation to exterior wall; remove stucco cladding, or add on top of it
insulationstucco
Related Solutions
The nature of task will depend on the exact type of wall. It would be best to wait for the inspection report before deciding anything.
If you have a cavity (for example) then it might be best to hire a professional. If you don't have a cavity then you need to add some insulation to the inside walls. You can get plasterboard with integral insulation which you can attach directly to the existing wall, but if you need more insulation you'll have to use thicker battens to allow for this. This will reduce the internal dimensions of your rooms. This is a job you can do yourself - but it is a big job.
Attic insulation is something you can do yourself too. The inspection should recommend what level of insulation you need to install.
I think I've answered my own question:
I'm going to do the footing insulation first. This will increase the effective thickness of the footings and result in a metal flashing plate over the footing foam at the bottom of the existing walls (for drainage and termite control/visibility).
I can use that for the wall project by resting the wall's new foam insulation on top of it. I haven't decided whether to screw the foam directly over the stucco or remove it first (see Adding insulation to exterior wall; remove stucco cladding, or add on top of it?), but regardless,during that time I'll remove the windows, build plywood bucks to put in new ones over foam and flush with the new stucco cladding, and flash them like so:
http://www.buildingscience.com/documents/insights/bsi-067-stuck-on-you
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Best Answer
Fastening rigid board by screwing through the stucco into the cladding (or framing) will hold the stucco in place, so its poor condition matters little. Remove any mold or rotted stucco, and remove any organic debris. I wouldn't bother trying to glue to flaking stucco.
Additionally, the stucco left in place will continue to provide a moisture, thermal, critter, and sound barrier that is desirable.
Advantages: cheaper, cleaner work, and easier to do.
Disadvantages: the exterior will be slightly (1/2 inch?) larger.
The only advantage I can think of to removing the stucco is the idea that you'll remember it as getting rid of the mess.