Updating house insulation
In old houses with plaster walls, there is no vapor barrier under the plaster so the wet air hits the insulation and condensates.
This wets down the blown-in insulation making it a wet mass at the bottom of the wall cavity creating an inviting place for termites and dry rot.
After about a year the wall should be dried out and you can fill the holes or replace the siding or stucco in those areas. Again, the primary issue for energy efficiency is stopping excessive air infiltration.
The next step is to go inside and install fiberglass, batting insulation between the 2" x 4" or 6" studs.Before the drywall can be installed over this wall, 4 mil thick plastic sheeting must be laid over the insulation on the entire wall. We create warm moist air in our homes by cooking, taking showers, having plants, breathing etc.That warm, moist vapor is attracted to the exterior walls.I've inspected thousands of old houses with blown-in insulation and over 80% of them have this wet insulation problem. Weather-strip your windows and doors, keep the house painted/caulked well, insulate the attic and box sills.This will stop the air infiltration, make you more comfortable and save money on utilities.
"Hey, wait a minute Bob, if we can't insulate the sidewalls, how can we afford to heat our old house? You should also friction fit foam board insulation into the box sills in your basement (the area where the beams or floor joists rest on top of the foundation).