Damp Cellulose in Wall Cavities
We are in the middle of a deep energy retrofit, and Wednesday before last we had a massive storm roll through. I had a section of west-facing wall that was stripped to the board sheathing that was pummeled by horizontal rain. The wall cavity is filled existing cellulose insulation, probably from the 70’s. When poking a finger into one of the installation holes or gaps between boards, it still feels damp to the touch.
We are wrapping the walls in a self-adhered vapor-permeable air barrier (Grace Vycor En-VS), followed by foil-faced polyiso foam. The interior walls are 100-year-old lath-and-plaster, with an unknown number of coats of paint. My question is:
1) Should we remove the old cellulose and blow in new before wrapping the sheathing, or
2) Go ahead and install the vapor-permeable peel-and-stick housewrap to prevent further water intrusion, but wait for a period to allow for drying, or
3) Is it safe to move forward with the housewrap and foam installation?
We are in Climate Zone 4, and having an unseasonably warm winter (temperature is 60F today). I appreciate any advice seasoned hands can offer.
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