On Feb 22, 12:33*am, frank1492 wrote:

A friend has a brick house and had insulation blown into the wallspace
through the inside walls. He describes the plugs used as "foam" which
I assume means styrofoam. He then proceeded to use lightweight spackle
prior to painting. After the spackle dried he noticed that the spackle
had turned slightly brown in color, necessitating the use of a stain
blocker.
* * * Although I didn't ask I assumed this had to be an oil based
spackle as water based would not have caused this, but isn't most
spackle water-based?
* * * What do you think happened?

Water-based is not the same as water - there's stuff in there, and
some of it must have reacted with the polystyrene and bled through.
He should bring it up with the insulation contractor. It's necessary
feedback for them whether or not they did something wrong.

R