| Crawl Space Mold Removal
and Remediation
Q. I have a serious mold problem in my crawl space which also
seems to be affecting my wife’s health. Over the past 6 months she has had
occasional asthma related systems, difficulty breathing, and irritated
eyes. She has a history of allergies but lately it has been unusually
bad. I purchased my house 3 years ago and a while back I noticed that my
dryer vent was not properly vented. I noticed a white growth on in my crawl
space where the vent was venting. I promptly re-routed the vent to one of
the crawlspace air vents thus pushing the air out of the house. Foolishly,
I did nothing to address the mold growth and now I have returned to the
crawl space months later, because of a plumbing leak only to realize that
the growth is much worse. I fixed my plumbing leak promptly but I still
have one more plumbing issue (corroded pipe elbow) that I am hoping to
address this week. The worst of the growth covers a 200 sq foot area but
there is sporadic growth throughout the crawl space. I did a swab test
using your advertised mold test kit and the results returned showed
aspergillus and cladosporium and two other strains I cannot remember but
have been told are very common and less dangerous. I had two remediators
come out and take a look. The first recommended a procedure including neg.
air fans, air scrubbing, Dehumidifiers, Hepa vacuuming, wire brush and
grinding of mold affected areas, hepa sanding mold affected areas, fungicide
wipe down, alcohol/mild detergent wipe down, and cleaning the exterior of my
heating ducts. He seemed fairly knowledgeable and his bid was for $7900.
The second contractor was much more vague but talked about much the same
process and an additional protective coating after cleaning is finished.
His bid was much higher at 15,000. I am leaning toward the $7900 bid
because the contractor seemed more trustworthy and knowledgeable. Does this
sound like an appropriate bid for this work? Does it seem too low? My
primary concern is getting this done right. Obviously I do not want this
problem to return. I also would like to be sure that I can get a
reasonably clean test after completion. I plan on attempting to sell my
house in the near future and will need to disclose the mold history. As you
know, a clean test is crucial to the selling of my home. The other concern I
have is my old gravity based heating system. It is not an HVAC but it
works fine and although the ducts contain asbestos, I was told by a heating
contractor there was no need to pull it out and replace until it stopped
working or began giving off carbon monoxide. I have not used it since I was
aware of the mold problem. I’m wondering if you know of anyway it can be
cleaned or tested for the mold? Do I have to remove it as well? Are there
any companies that do both asbestos and mold remediation? [October 21, 2005]
A.
The lower priced estimate seems reasonable for crawl space mold remediation,
but review and be sure the remediator does the 25 steps for safe and
effective
mold remediation. It is very important that you also mold test all
rooms of the home, attic, and the outward air flow from each heating/cooling
duct register for the possibility of elevated levels of airborne mold
spores, in comparison to an outdoor mold control test. Crawl space mold can
easily grow into the insides of the walls and floors above. In addition,
airborne mold spores can readily travel in air currents from the crawl space
mold to enter your open through open windows and doors to mold cross
contaminate your entire house and its heating/cooling system. Follow the
mold inspection and testing tips at
Mold Inspection. As part of safe and effective mold remediation, you
would be wise to replace the asbestos-lined ducts [probably also mold
contaminated] and the old heating/cooling system with a modern one to
facilitate the mold remediation as to help you sell your home for the most
favorable price. Many asbestos contractors are also mold remediators.
Q.
I recently bought a 1500 sq-ft bungalow cottage which has a full foundation
(concrete poured on bedrock). The cottage is located on a lake near the NY
and Ontario Boarder. In this area we have cold winters (down to -25F and
warm and hummid summers that reach 94F). The building was built in 3 stages.
- The part that was built in 1970 is 900 sq-ft 50% of the basement is 7-ft
high with concrete floor (where the furnace, hot water tank etc. are
located) and the rest of the basement is crawl space. The crawlspace is soil
and covered with vapour barrier sheets placed loosely on the soil (the
vapour barrier is not sealed with acquostic caulking and tape to the
foundation, and the sheets overlap about 2 inches). This part has 3 windows,
each 1 sq-ft to the outside and a small sump pit (there is no sump pump, so
I assume the pit gravity drains to the septic tank) - A 16x24 ft addition
built in 1995 has crawl foundation on bedrock and crawl space (average 2.5
to 3.5 ft high). In this part also there vapour barrier is placed loosely
over the soil. There is a 3 sg-ft opening to the area built in 1970, and a 1
sq-ft window to the outside. - Another 16x16 ft addition was built in 1999,
it has no openings to the other basement areas, its crawlspace is over
bedrock and has no vapour barrier on the rock. There is an access door from
the outside. - This July I noticed there was a lot of condensation on the
vapour barriers. This prompted me that I should leave the basement windows
open. Still with the basement windows I noticed a bit of condensation on the
vapour barriers. Then suddenly I noticed a patch of with mold growth on a
concrete section next to the edge of the vapour barrier. I removed it and
then applied a lot of Ammonia to it. A week later, the mold was growing in
the same spot on the concrete again. Upon closer inspection, I see that
under the vapour barriers there are white/greyish material that should be
mold. I haven't noticed any problem in the 16x16 section were crawl space is
on solid rock. - I only use the place on weekends from June through October,
and do not heat it in the winter. Per the neighbours, the original owners
apparently had no problem with mold, but had some moisture problem that they
apparently addressed by leaving the 4 windows in the basement open. To
address the current mold, a contractor told me that they can would another
sheet of vapour barrier, seal it and pour 3 inches of concrete over it in
the crawt spaces (original building and 16x24 section) and they claim this
would seal the mold in. Another contractor told me all I have to do is
proper vapour barrier over the present section and not remove the old vapour
barrier to disturb the mold. Another contractor suggests sealing the walls
and basement ceiling, removing an inch of soil, treating with chemicals, and
the re-doing the vapour barrier. To prevent recurrence, our local building
inspector is saying that its better to run a dehumidifier and leave a couple
of windows in the basement slightly open for getting fresh air. (And maybe a
fan that would help circulate air between the original building and the
older section). I appreciate your help on what is the best approach--- 1.
the current mold (seal it in with vapour barrier, or remove soil then seal
it in, or other), and 2. to prevent recurrence (dehumidifier with a bit of
fresh air, or just fresh air -- I can even place fans in front of a couple
of basement windows to blow fresh air in). 3. What should I do with the
first floor? No problem yet. Should I run dehumidifier on 1st floor as well,
or leave some windows open? 4. What is the best for the 16x16 crawl space
area that is over solid rock and has no direct opening to the other areas?
[Sept. 7, 2005]
A. You have received good recommendations from all of your
interviewed contractors. Actually, the best approach is to combine their
various good ideas into one overall mold remediation and prevention strategy
for the crawl space. The recommendations made below should be read and used
in the context of the overall 25 steps for safe and effective
mold remediation.
Removing the crawl space dirt mold growth and one inch of dirt in the ground
beneath the moisture barrier is certainly wise for effective crawl space
mold removal and remediation. Then place one or two thick plastic
sheets [6 mill thickness each sheet] over the ground. Then pour a concrete
floor in the various crawl spaces over the plastic sheeting, but the
concrete needs to contain adequate amounts of waterproofing compound to make
the concrete floor an absolute water barrier to water wicking up into the
concrete and thus into the crawl space air from the ground below [plastic
moisture barriers degrade over time]. You would also be wise to
use a low-cost
Mold Home Remedy Recipes and other Mold Killing and protective
products available at Mold Mart. To stop a buildup of airborne mold
spores and to reduce crawl space humidity that facilitates mold growth, you
might want to install a humidity controlled fan in each of the crawl spaces
to exhaust crawl space air when it exceeds 50%, with 30 to 40% turn-on level
is even better because 30 to 40% humidity discourages mold growth.
25 Mold
Remediation Steps |
