I have a 50 yr old row house. Never had a water problem... except for
during Isabella, the sump pump didn't work and water backed up into the
finished basement. I dried everything out and didn't think much of it.

Fast forward 5 years, and I have the house up for sale. Buyer made an
offer contingent on mold test. (My agent didn't know why as she hadn't
noticed anything, other than it smelled a bit musty from the house
(vacant) being closed up. I have asthma to cats, dogs etc and never had
a problem). Test came back "high" for several types of mold, including
the stachy stuff. They also saw, but didn't test for, mold on attic
rafters. Buyer bailed.

I had one company (name dropped by the home inspector who did the
testing) come in. He told me the only way to eradicate it was to
completely rip out all of the knotty pine and go down to the cement. $8K
(reduced from $11) for that and sanding and encapsulating the attic
beams. I had a second company come out. His version is that the basement
doesn't need to be demo'd, that the mold is on the surface of the
paneling (and that it normally feeds on wallboard etc, not wood) and can
be treated by sanding and using clear encapsulant, the same as both of
them propose for the attic, and it will pass the next round of tests.
For $3400, including retest. Claims the first guy is just in it for the
money. I'm not sure the 2nd guy is necessarily accurate (although I want
him to be!) or is saying that depending on how the tests are performed,
they can be "made" to say anything. He also said he doesn't believe the
first set of tests, that if they were accurate, everyone would be sick,
and the walls would look like the photos he showed me of someone with
far less count. He says the home inspector must have done the tests
wrong, sticking it directly in one of the small pockets of mold rather
than testing the air. Both companies agree that the stuff in the attic
may well have been there since the house was built, as back in the day,
people didn't care if there was mold on the wood which had been sitting
outside. Both agree the probable source was the sump pump overflow (sump
was replaced during that episode, and no further problems). Oh and 1st
guy claims he can see mold spores on the paneling. Second guy says he can't.

I'm trying to sort out just what IS going on and what the right answer
is. I don't want to have to tear out and rebuild the "clubroom" in a
house I no longer occupy if I don't have to, but I don't want to
endanger anyone (or any sale!) if it truly is necessary. I have a 3rd
company coming out this week. She has just seen the test results, and
also feels that many home inspectors don't know how to collect the tests
correctly, and says generally knotty pine doesn't need to be removed.

Sorry. Long tale, I just get so upset every time I try to tell it! What
I'm asking at this point (in addition to does anyone have any thoughts
on these scenarios) is - are these companies known for having a high
incidence of scammers?