We are replacing all of our downstairs flooring. Hardwood will replace
carpet in the living/dining/den and either Duraceramic or sheet vinyl in the
kitchen. The kitchen floor luan had delaminated in several places.
To save a few dollars I have pulled up the carpet & pad and have now pulled
up the old vinyl and luan in the kitchen. In the living/dining/den the
subfloor was nice and clean. However in the kitchen/laundry/bath area the
subfloor is covered with a white powery substance. I believe it is a mold
of some type. There were also a couple of small spots that were green and I
know this to be mold. However these spots were relatively small areas of
about 6" in diameter. The kitchen/bath/laundry happens to be over the area
of the crawl space that has a congestion of HVAC ducts etc. So ventalation
under the back of the house is not as good as in the front of the house.
There is no evidence of leaking toilets, sinks, dishwashers etc. The
subfloor is solid and dry. Underneath the house I can't find any evidence of
pipes spraying upward etc.
I want to make sure that I handle any problems now before a new floor is put
down.

Do you think this is mold?

If so would several moppings or sprayings of a water/bleach solution hel;p
or hurt?

Would moisture be rising through the joints of the subfloor?

Should I caulk the subfloor joints?



Thanks
JD

don't know if this helps but recently had the refrig leak. 1st
indication was Wood floor warp about 4 feet from the frig itself......
wood flooring company came out to check the damage. They had to wait 3
months for it to dry out before doing any service to the floor. They
said things need to be good and dry before sanding and sealing anything.