Hi chilliewillie,
Thank you for your question.
As you know, if you clean up the mold, but don't fix the water
problem, then, most likely, the mold problem will come back.
=========
Regarding the type of foundation you have:
http://www.askthebuilder.com/403_Foundation_Choices_Are_Many.shtml
"A foundation system that sports a crawl space is indeed a step or two
above a slab foundation."
[...]
"Crawl space foundations allow you to install plumbing and heating
utilities so that they are accessible. The floor system over and the
foundation walls inside of the crawl space almost always need to be
insulated. A high performance vapor barrier that is sealed to the
foundation walls must be placed over the soil in the crawl space. If
this vapor barrier is missing, water vapor will readily travel up into
the wood floor system and then into the house. This water vapor can
cause severe mold problems."
=========
Ongoing Water Seepage into the Crawl Space
http://www.soundhome.com/consult/271to280.shtml
Question:
"My House is on a slope. The crawl space is about 8 ft high. The
ground in the crawl space has two levels. Even with light rain there
is water seepage from the side of the step. There are two drain holes
at the lower corners. Is the seepage normal?"
Answer:
"Yes, your home may be located on a lot with ongoing seepage. It
sounds as if you have a very large crawl space, and that should help
you cope with this situation. I am assuming that the roof drainage and
grading at the perimeter of the house is in good order. If all that is
O.K., here are the next few steps:
First of all, I would create a channel for the drainage to exit the
crawl space and drain to the outside. The "two drain holes at...." may
have been intended for that purpose."
[...]
"I would then install a perforated drain tile into the channel and
encase the drain tile in gravel. Once this is done, I would cover the
whole area with a plastic vapor barrier.
The second step is to make sure that you have lots of screened crawl
space vents and lots of cross ventilation through the crawl space.
This crawl space is a good candidate for additional venting.
Once this system is in place, take a look at the crawl space from time
to time to make sure that all of the drainage is contained in the
channel and under the vapor barrier."
=========
Crawl Space Venting
http://www.soundhome.com/consult/271to280.shtml
Question:
"During your inspection of our house you remarked that our crawl space
is unvented. I have a rotary hammer. Would it be advisable to bore a
couple of well placed holes through the exterior wall and cover the
holes with screen? Is it critical to vent this area?"
Answer:
"Yes, screened vents should be installed at the perimeter of the crawl
space. The vents need a net area of 1.5 sq.ft. per 25 linear feet of
exterior foundation wall. The smaller and less voluminous the crawl
space, the more venting it needs. Vents should also be installed in
such a way as to maximize cross venting. The soil grade at the
exterior of the vents must grade away from the structure and prevent
water entry.
Crawl space vents are important, but will not dry out an already wet
crawl space. So don't forget about good quality gutters, downspouts
and drain systems."
=========
Mold Growth and Remediation in a Crawl Space
Mold removal in homes with indoor moisture problems by Thad Godish, Ph.D
http://www.allergyconsumerreview.com/mold-growth.html
Question:
"Our crawl space gets a great deal of moisture, and has resulted in
mold growing on the floor joists."
[...]
Answer:
"Wet/moist crawl spaces are common here in the Midwest because of the
high clay content of soils in many building sites. Such soils are
poorly drained and as such water often sits in crawlspaces for weeks
or more during rainy periods of the year. This is even the case when
pea gravel and polyethylene plastic are put down (though they likely
do help). The problem is further exacerbated if the crawlspace has few
or no vents, the vents are blocked by shrubbery, or vents are closed.
When the house was built, the drainage should have been put in place
around the perimeter of the house as well as under it to carry the
water away.
Because of the moisture, high relative humidity occurs in the
crawlspace that provides an optimum environment for mold growth. The
problem may be made worse by subsequent condensation on floor joists
and other wood materials.
My experience with wet crawlspaces is that they are major sources of
mold growth and subsequent human exposures in living spaces. As such,
it is highly probable that the allergy problem that your son has is
associated with your house.
Before you attempt to remediate the problem, you should have the
crawlspace inspected by a professional to ascertain the true nature of
the problem. I can only provide generic advice. This includes:
vacuuming all infested timbers with heavy-duty vacuum cleaner (minimum
5 horsepower), brushing with a stiff brush, re-vacuuming and
application of mold-inhibiting paint to both seal the mold in and
prevent it from growing. This should be done taking appropriate safety
measures (approved respirator, disposable/washable clothing, gloves,
etc. ).
Mold infestation will return if the drainage problem is not resolved.
This will require engaging a professional to install an appropriate
drainage system."
=========
Solving persistent moisture problems and moisture damage
http://alcor.concordia.ca/~raojw/crd/reference/reference000211.html
"... the building started showing symptoms of moisture damage. The
symptoms appeared after the owners replaced the heating system boiler,
installed a combustion air inlet in the boiler room, installed a new
roof, sealed some air leakage and changed crawl space ventilation.
Contractors asked for solutions to the moisture problems provided
conflicting recommendations, some quite costly. The owners hired an
impartial consultant to determine the source of the problems and
recommend solutions.
The consultant concluded that poor site and crawl space drainage
allowed large quantities of moisture to enter the crawl space. The
moisture from the crawl space caused high humidity in the apartments.
In cold weather, the high humidity cased deterioration of the building
envelope, poor air quality and mold growth on walls.
The consultant recommended grading the crawl space, installing sump
pits and sump pumps in the crawl space, landscaping the site to drain
surface water away from the building and installing exhaust fans in
the crawl space.
The project cost $13,910, plus GST. Moisture and mold problems have ceased."
=========
http://www.bsu.edu/web/IEN/archives/070204.htm
Question:
"We have a crawlspace problem. We noticed that the insulation and wood
is wet. The plumber detected no leaks and said it was due to
condensation. We had two different mold removers tell to us two
different remedies: (1) a house and crawlspace dehumidifier (Humidex)
and (2) a new drainage system for removing moisture under the existing
plastic vapor barrier."
[...]
Answer:
"If one does have a moisture problem in a crawlspace, it will
typically require some combination of improved drainage and
ventilation to resolve. Remediation will also require the treatment of
the crawlspace timbers with a polyborate-containing paint to both
inhibit mold growth and to ?lock? mold spores in.
Mold requires high humidity of liquid water to grow. Scientific
studies indicate that little or no mold growth occurs below relative
humidities of 75%. As such, your goal should be to maintain
humidities below 75% with values not to exceed 70% as your target.
Each individual remediator has some sense of the need to reduce
humidity levels. They are suggesting different approaches. Each has
some potential to work by itself but it is likely that a combination
of drainage and ventilation will be needed. If your house is near a
coastal area, the crawlspace problem may be even more complicated. In
coastal areas, high crawlspace humidity may actually occur as a
consequence of outdoor air moving into your crawlspace and then
condensing. In such circumstances, one may not have a drainage
problem and ventilation is a major part of the problem. In such cases
closing crawlspace vents is recommended."
=========
Hazardous Mold Growth in the Home
http://www.askthebuilder.com/344_Hazardous_Mold_Growth_in_the_Home.shtml
"The temperature inside of most homes, crawlspaces and attics is
almost always sufficient to support mold growth."
[...]
"The key to stopping or halting mold is to cut off its supply of
water. Vent dryers outdoors. Install high quality fans that remove
water vapor from baths and kitchens. Cover crawlspace dirt with high
performance vapor barriers. Fix plumbing and roof leaks immediately.
Stop water infiltration into basements and crawl spaces by installing
hidden linear french drains around your home. These simple trenches
filled with perforated pipe and gravel can intercept and redirect
water away from your home. Install excellent ridge and soffit
ventilation systems. Seal leaks in brick homes caused by wind driven
rains with high performance breathable silane and siloxane water
repellents. You can stop your mold growth by lowering the relative
humidity in your basement or by raising the indoor temperature."
=========
An excellent article on Linear French Drains can be found at:
http://www.askthebuilder.com/printer_070_Linear_French_Drains_-_Controlling_Basement_Seepage.shtml
=========
Mold in My Home: What Do I Do?
http://www.cal-iaq.org/mold9803.htm
GENERAL CLEAN-UP PROCEDURES
Identify and correct the moisture source
Clean, disinfect, and dry the moldy area
Bag and dispose any material that has moldy residues, such as rags,
paper, leaves, or debris.
What can I save? What should I toss? Substances that are porous and
can trap molds, such as paper, rags, wallboard, and rotten wood should
be decontaminated and thrown out. Harder materials such as glass,
plastic, or metal can be kept after they are cleaned and disinfected.
Ultimately, it is critical to remove the source of moisture first,
before beginning remedial action, since mold growth will return
shortly if an effected area becomes re-wetted.
Removal of Moldy Materials After fixing the moisture source and
removing excess moisture, the cleanup can begin:
Wear gloves when handling moldy materials
Remove porous materials (examples: ceiling tiles, sheetrock,
carpeting, wood products)
Carpeting can be a difficult problem -- drying does not remove the
dead spores. If there is heavy mold, disposal of the carpet should be
considered
Bag and discard the moldy substances
Allow the area to dry 2 or 3 days
If flooded, remove all sheetrock to at least 12 inches above the high
water mark. Visually inspect the wall interior and remove any other
intrusive molds. (This step may have to be carried out by a licensed
contractor).
CAUTION: Spores are easily released when moldy material is dried out.
Soap Cleanup
Before disinfecting contaminated areas, clean the areas to remove as
much of the mold (and food it is growing on) as possible.
Wear gloves when doing this cleanup
Use a non-ammonia soap or detergent, or a commercial cleaner, in hot
water, and scrub the entire area affected by the mold
Use a stiff brush or cleaning pad on block walls or uneven surfaces
Rinse clean with water. A wet/dry vacuum is handy for this.
Disinfect Surfaces
Wear gloves when using disinfectants
After thorough cleaning and rinsing, disinfect the area with a
solution of 10% household bleach (e.g., 1½ cup bleach per gallon of
water). Using bleach straight from the bottle will not be more
effective
Never mix bleach with Ammonia - the fumes are toxic
For spraying exterior large areas, a garden hose and nozzle can be used
When disinfecting a large structure, make sure the entire surface is
wetted (floors, joists, and posts)
Avoid excessive amounts of runoff or standing bleach
Let disinfecting areas dry naturally overnight -- this extended time
is important to kill all the mold.
CAUTION: Bleach fumes can irritate the eyes, nose, and throat, and
damage clothing and shoes. Make sure the working area is ventilated
well.
Can cleaning up mold be hazardous to my health?
Yes. Exposure to mold can occur during the cleaning stage. Mold counts
are typically 10 to 1000 times higher than background levels during
the cleaning of mold damaged materials. Take steps to protect your
health during cleanup:
When handling or cleaning moldy materials, consider using a mask or
respirator to protect you from breathing airborne spores. Respirators
can be purchased from hardware stores; select one for particle removal
(sometimes referred to as a N95 or TC-21C particulate respirator).
Respirators are not as effective removing bleach fumes, so minimize
your exposure when using bleach or other disinfectants.
Wear protective clothing that is easily cleaned or discarded
Use rubber gloves
Try cleaning a small test patch of mold first. If you feel that this
adversely affected your health, you should consider paying a licensed
contractor or professional to carry out the work
Ask family members or bystanders to leave areas when being cleaned.
Work over short time spans and rest in a fresh air location.
Air your house out well during after the work
CAUTION: Never use a gasoline engine indoors (e.g. pressure washer,
generator) -- you could expose yourself and your family to carbon
monoxide.
Can Air Duct Systems become Contaminated with Mold? Yes. Air duct
systems can become contaminated with mold. Duct systems can be
constructed of bare sheet metal, sheet metal with an exterior fibrous
glass insulation, sheet metal with an internal fibrous glass liner, or
made entirely of fibrous glass. If your home's air duct system has had
water damage, first identify the type of air duct construction that
you have. Bare sheet metal systems, or sheet metal with exterior
fibrous glass insulation, can be cleaned and disinfected.
If your system has sheet metal with an internal fibrous glass liner,
or are made entirely of fibrous glass, the ductwork normally will need
to be removed and discarded. Ductwork in difficult locations may have
to be abandoned. If you have other questions, contact an air duct
cleaning professional, or licensed contractor.
After I've cleaned everything as thoroughly as possible, can I still
have mold odors? Yes. It is possible that odors may persist. Continue
to dry out the area and search for any hidden areas of mold. If the
area continues to smell musty, you may have to re-clean the area again
(follow the cleaning steps given in this sheet). Continue to dry and
ventilate the area. Don't replace flooring or begin rebuilding until
the area has dried completely.
How can further damage to my home be prevented? Check regularly for the following:
moisture condensation on windows
cracking of plasterboard
drywall tape loosening
wood warping
musty odor
If you see any of the above, seek out and take steps to eliminate the
source of water penetration, as quickly as possible.
Can Ozone air cleaners help remove indoor mold, or reduce odor or
pollution levels? Some air cleaners are designed to produce ozone.
Ozone is a strong oxidizing agent used as a disinfectant in water and
sometimes to eliminate odors. However, ozone is a known lung irritant.
Symptoms associated with exposure include cough, chest pain, and eye,
nose, and throat irritation. Ozone generators have been shown to
generate indoor levels above the safe limit. Furthermore, it has been
demonstrated that ozone is not effective in controlling molds and
fungi, even at high concentrations far above safe health levels. Also,
ozone may damage materials in the home. For these reasons, the
California Department of Health Services strongly recommends that you
do not use an ozone air cleaner in any occupied residential space.
=========
Mold Resources
http://www.epa.gov/mold/moldresources.html
=========
What to Wear When Cleaning Moldy Areas
http://www.epa.gov/mold/whattowear.html
=========
Moisture and Mold Prevention and Control Tips
http://www.epa.gov/mold/preventionandcontrol.html
==========
A Brief Guide To Moisture, Mold and Your Home
http://www.epa.gov/mold/images/moldguide.pdf
This Guide provides information and guidance for homeowners and
renters on how to clean up residential mold problems and how to
prevent mold growth.
=========
http://www.fema.gov/diz01/d1364n18.shtm
"Be careful when cleaning mold," said Louis H. Botta, the Federal
Emergency Management Agency (FEMA) official who is the federal
coordinating officer for the disaster recovery effort."
[...]
"Molds are simple microscopic organisms found virtually everywhere,
indoors and outdoors. When mold is present in large quantities it can
result in allergic symptoms similar to those caused by plant pollen.
Be aware that exposure to mold can occur during cleanup. To minimize
exposure, use a mask or respirator, wear rubber gloves and take breaks
in a well ventilated area.
"You should be concerned about mold if the amount is extensive," said
Stephen J. McGrail, director of the Massachusetts Emergency Management
Agency and state coordinating officer.
When airborne mold spores are present in large numbers they can cause
allergic reactions, asthma episodes, infections, and other respiratory
problems. People who are at higher risk from the effects of mold
include infants and children; the elderly; people with compromised
immune systems because of HIV infection, liver disease, or in
chemotherapy; pregnant women; and people with existing respiratory
conditions such as allergies, multiple chemical sensitivity, and
asthma. People with these conditions should consult a physician if
they are experiencing health problems.
Here are some tips for cleaning mold:
Identify and correct the moisture source. Then clean, disinfect, and
dry the moldy area. Keep the area well ventilated and dispose of
anything that has moldy residue, such as rags, paper, leaves or
debris.
Porous materials can trap molds. Items such as paper, rags, wallboard
and rotten wood should be thrown out. Harder materials such as glass,
plastic and metal can be kept after they are cleaned and disinfected.
Wear protective gloves, such as rubber dishwashing gloves, when
working with moldy materials. Remove and discard porous materials such
as ceiling tiles, sheetrock, carpeting, wood products.
Carpeting can be a difficult problem. Drying does not remove the dead
mold spores. If there is heavy mold on the carpet, the best course of
action may be to discard it. If the area was flooded, remove sheetrock
to at least 12 inches above the high water mark. Allow the area to dry
two or three days before replacing damaged materials.
Wear protective gloves when cleaning mold. Use non--ammonia soap or
detergent, or a commercial cleaner in hot water. Scrub the entire
affected area thoroughly using a stiff brush or cleaning pad. Then
rinse with clean water.
Wear protective gloves when using disinfectants. After thorough
cleaning and rinsing, disinfect the area with a solution of 10 percent
household bleach (11/2 cups bleach per gallon of water). Never mix
bleach with ammonia. The fumes are toxic. Allow disinfecting areas to
dry naturally overnight to kill all mold."
=========
Mold in Homes
http://www.health.state.mn.us/divs/eh/indoorair/mold/index.html#cleanup
Scroll to Mold Clean-up and Removal
=========
Mold Remediation Guidelines
http://www.ncsu.edu/ehs/www99/right/handsMan/air_qual/mold_remediation.htm
See links on left side of page:
Prevention
Hidden Mold
Remediation Plan
Remediation
Cleanup Methods
Personal Protective Equipment
Containment
=========
Scroll about halfway down the page to: Solutions to Mold Problems
-Materials You Will Need
http://www.fema.gov/txt/reg-v/fema_mold_brochure_word.txt
=========
Hiring a Mold Consultant or Contractor
http://www.epi.state.nc.us/epi/oii/mold/consultant.html
=========
CONTROLLING MOLD GROWTH IN THE HOME
http://www.oznet.ksu.edu/library/hous2/MF2141.PDF
=========
Allergies Mold, Moisture and Your Home
http://allergies.about.com/library/blmold06.htm
Who should do the cleanup?
=========
keyword search:
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=========
Best regards,
tlspiegel |
