I live in an old house, circa 20's, that has a finished basement. To
the rear of the boiler is a plastered wall which apparently abuts the
chimney sump. For as long as I can remember, the plaster was
intact and held a coat of decorative paint with no sign of
deterioraion.
Over the past year, the plaster has started to crumble. I was
away for the summer and returned to find it had gotten much worse.
We have had several severe rainstorms here over the summer, but
the fireplace is bone-dry.
Could anyone venture a guess as to why water might be getting
into the sump but not the fireplace? Or perhaps there is another
reason for the erosion other than moisture.
May I have your thoughts?
Thanks.
Frank