Mold on carpet

Jessica Fletcher <jfletcher [at] denverartmuseum__org>

>We recently experienced minor flooding under the floor carpets in
>the elevator lobby of one of our galleries.  As a result, mildew is
>starting to grow.

Regarding the mildew problem. Moisture must be removed from both the
environment (floor) and the carpet. I would mop up all moisture
using clean rags or paper towels (white) using a blotting, not
rubbing action, and check the white towel for dye coming off of the
rug. Dry out the rug. If you have a room dehumidifier, that would
also dry out the air in the room.

I would not let the carpet be exposed to direct sunlight due to
fading. The problem is that you have several deteriorating factors
working at once; 1. Water staining-dirt may be carried to the edge
causing "tide marks." 2. Mold grows in moisture, high humidity high
temperature conditions; above 68 degrees F and above 65% relative
humidity approximately.

The active mold produces spores which can spread to other materials
as well as grow on the infected item. Mold does not grow well in
moving air. Large fans can also reduce the growth of the mold and
also help dry out the carpet.

As regards treatment, I have used thymol for years in treating works
of art, books etc. for active mold and as a deterrent. Thymol comes
in crystals, and is slightly soluble in water, but very soluble in
alcohol. You can get thymol crystals from B.L. Haymond Supply,
707-462-5011. Tell them James French referred you to them.

The solution should be 10% weight per volume, and for very sensitive
materials I would use Isopropyl alcohol which can be bought in a
drug store, which is 70%  per volume. Even though you are
introducing 30% water in the solution, when concerned about color
dyes, a weaker alcohol is desirable. You could also use straight
isopropyl if you can obtain it. Ethyl alcohol also works, but is
stronger, but test on small area or back of rug regardless of what
you use. Put a small amount on a cotton swab or Q-tip to test for
color bleeding etc.

The crystals are slowly dissolved in the alcohol and stirred. The
mixture can be sprayed on with a paint sprayer such as Prevalve
which has a container and a compressed air unit on top and is
sprayed just like a spray can. Some paint stores sell this item.

Beware, thymol exposure in lungs, eyes, skin etc. Spray in well
ventilated area. Wear gloves and goggles when mixing and spraying.
If any gets on you, wash with plenty of water. It is not corrosive,
but an irritant and can burn the skin and cause redness. The smell
can be very strong, but will eventually go away. Several
applications over time is good. Thymol is used in Listerine
Mouthwash is very small amount.

Thymol sprayed on when the item is damp may help prevent or slow
down the mold growth. When you can't smell it anymore over time, its
effectiveness is gone.

The above information is given from my experience, and if used by
you or anyone else is done at your own risk, and I am not
responsible for any damage to persons or property or cultural
materials. I would also test using thymol on some other object
before actually testing or spraying on an important item.

James French, G.W.I.C.


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                  Conservation DistList Instance 14:41
                 Distributed: Monday, January 29, 2001
                       Message Id: cdl-14-41-006
                                  ***