Carpet Stain and Damage Repair Q&A
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Dear NH,
I have recently carpeted a Florida room and I am getting a dark gray to
black stain on the carpet all along the perimeter where the carpet meets the
baseboard. The stain is only about 1/2" wide but it occurs along all four
walls. The room is on a cement slab with a particleboard sub floor. I suspect
that the stain has something to do with the cement underneath. I am willing to
re-carpet the room but what can I do to keep this stain from recurring? I'd
appreciate any help you could offer.
LI from Dearborn, MI
Dear LI,
Water (or water vapor) bringing "something" through the subfloor
into the carpet is probably causing the stain. It could be mildew growth or it
could be some sort of chemical stain. Since it is only around the perimeter, I
am wondering if perhaps some sort of sealant or plastic tarp was used to cover
the slab and moisture is leaking around the edges, producing the damp spots.
You may want to take up some of the subfloor and look underneath the see
what's going on. If there is excessive moisture, you might want to remove the
entire subfloor and seal the slab with waterproof cement paint. I would consult
your local hardware or home store to find the correct product for this
application in your area.
If they are not already installed, laying overlapping plastic tarps on the
slab will also decrease the moisture infiltration. They should overlap at least
a few feet and be pressed tightly around the perimeter of the slab. Ideally, the
perimeter should be held in place mechanically with wood strips nailed to the
slab. In inaccessible areas, one trick that can be used is to pour sand or
gravel over the tarp to stabilize it.
You could, of course, consider putting down heavy plastic tarps underneath
the carpet and padding. My advice is… DON'T DO IT! This would indeed isolate
the carpet from whatever is causing the problem, but... a really BIG but... you
will also be sealing the subfloor as well, and the additional persistent
moisture will speed the growth of wood rot fungus.
Dear NH,
There is a draft at the bottom of the walls in my games room. The edge of
the carpet is black. How can I repair this problem?
CS from British Columbia, Canada
CS,
Its difficult to know for sure why you are having this problem, but what is
sure is that you have an air leak coming under the base molding, blowing oily
dust or dirt onto the carpet. Odds are, there is an air space between the floor
and the wall, allowing air to enter your room from the hollow in the wall or
from the basement/ floor below.
What you need to do is seal the leak. The more difficult way would be to
remove the base molding and install some sort of air barrier... depending on
the size of the leak you could use a strip of plastic or even a foam insulation
pressed into the gap.
Since I can reasonably guess that you would prefer a less destructive
solution, try this...
Pull the carpet back from the areas where you have the leakage. You will
probably see a gap under the moldings where the air is entering. Purchase some
strip foam insulation... this product is available in a number of sizes. Don't
buy the kind with a glue strip... it is unnecessary and probably will make
installation difficult or impossible. The type I mean is the type used to
weather strip air conditioners... just ask... all the good hardware store guys
will know what I am talking about.
Again, depending on the size of the gap, you may have to cut the foam
insulation into a thinner strip. Plain old scissors will do the job nicely. Push
the foam into the gap between the base molding and the floor. This will stop
the air infiltration dead in its tracks, along with the staining!
Dear NH,
I have a 5-year-old home that I had constructed for my family.
Unfortunately, we have started to see a fine gray like staining on
the carpets on the interior walls especially near the cold air
return and, oddly enough on the ceiling of the home where the
trusses are located. We have been able to paint over the stains on
the ceiling but have not been able to determine the source of what
is possibly causing the problem.
We have been told that we may have poor ventilation in the
attic, but that does not appear to be a problem. We do have all
gas appliances and was wondering if that might be the problem.
M from Midland, Michigan
M,
Usually these persistent recurring accumulations of dust and
dirt are related to condensation and temperature variations. The
stains often seem to follow the line of the ceiling joists and
sometimes wall studs on outside walls. The joists create a direct
path for the cold from the attic to enter your living space! This
is because wood is less of an insulator than the rolled or loose
insulation between the joists on the attic floor.
These cold spots cause normal home moisture to condense on the
ceiling… not enough to drip but enough to act as a "dust
magnet" and, over time, cause the telltale accumulations of
dirt and subsequent staining.
Repainting will eliminate the stains for a while, but because
you have not addressed the cause of the staining it will recur
eventually. Using an eggshell (or glossier) finish paint instead
of flat will help make the surface easier to clean.
One way to lessen this problem is to add insulation to the
attic across the tops of the joists. This will equalize the
temperature of the ceiling and (hopefully) eliminate the recurring
stains.
You mentioned your natural gas appliances. One of the main
byproducts of burning natural gas is water vapor. This additional
moisture can be a problem in some homes, especially new homes that
are built to be very weather-tight. You can lessen the moisture by
increasing ventilation... use the exhaust fan over the stove
whenever possible, use the exhaust fans in the bathrooms, etc...
even open a window!
Hope this helps!
NH
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