In the
process of trying to sell our home, the potential buyers had our
crawl space tested for mold. The results were not bad but there was
some mold. The Aspergillus/ Penicillium levels of the initial test
(Air-O-Cell) came back at 2237 counts/m3. After a $6000
remediation, the space was retested; the results of these Air-O-Cell
tests were Aspergillus/ Penicillium 923 counts/m3 and
basidiospore 2230 counts/m3. A different testing company
has now said that the mold problem has not been remediated (with
these test results). Our remediation company says that Aspergillus/
Penicillium levels in the outside test were at 1450 counts/m3
(though the basidiospores in the outdoor test were only at 200
counts/m3). What are your feelings on the remediation?
Was it successful or should we have our remediation company do
further remediating?-Erin,
Ohio
If you read this website posting of
September 2, 2005 (see archives), you will soon note that I have
very little confidence in using test results reported by commercial
laboratories in mold-related decision making relative to whether (1)
a mold problem exists in a building space, (2) whether to remediate,
and (3) how good was the remediation?
Crawlspace mold concentrations are
invariably higher than those in indoor spaces even when no
significant mold infestation exists in the crawlspace and no
significant mold exposure is occurring in building living spaces.
There are several issues that
complicate the concerns you have relative to test results and the
remediation. Firstly, it appears that pre-remediation and
post-remediation testing was conducted by different
individuals/companies. In such a case, it would not be surprising
that analyses were conducted by different laboratories. The
apparent pre and post-remediation differences may be due to count
variability among laboratories or even among analysts from the same
laboratory. Though the pre and post Aspergillus/Penicillium
values indicate that an approximate 60% reduction occurred, this
difference is well within the range of variability that one can
expect between different laboratories or even two different analysts
in the same laboratory. Differences could even be due to normal
variation in airborne mold that may be associated with environmental
conditions in your crawlspace.
Assuming the basidiospore count is
correct, the post-remediation test results suggest that there may be
a mold problem in your crawlspace. Basidiospores are commonly
produced by wood-decay fungi. Basidiospores are relatively large
and are easily counted even at magnifications as low as 600 or
400X. As such, basidiospores are more likely to be reliably counted
and reported than Aspergillus/Penicillium.
Higher crawlspace than outdoor
basidiospore concentrations suggest that either a wood decay problem
(and thus mold) exists in your crawlspace or did exist prior to
remediation. Any kind of remediation activity in a crawlspace is
likely to dislodge fungal spores that because of the nature of a
crawlspace can remain there to be re-suspended from the disturbance
of crawlspace dust.
You did not mention the presence of
basidiospores in pre-remediation testing. I suppose that reflects
the fact that none were reported (which is somewhat surprising). If
such counts were conducted competently, then the basidiospores would
have had to be released as a result of the disturbance of wood
timbers during the remediation.
It is not possible from the test
results to conclude (1) that your crawlspace and your house had a
mold problem to begin with and (2) whether an attempted remediation
accomplished anything. As such, what is a person to do? One is
limited to conducting a thorough visual inspection by an experienced
and competent mold inspector to determine whether any significant
mold growth has occurred on crawlspace timbers and if so, is there
physical evidence that it has been adequately remediated?
September 9, 2005
