Basement crawlspace / moisture

[Christopher]

We were told that we should use tarps or something similar to prevent moisture in our basement crawlspace. We were told that we should put them on the ceiling of the basement, as well as over the stone floor. This was told to us by the home inspector when we bought our house about three months ago. The basement is bone dry right now, but there is a fan down there and a dehumidifier that is working on the lowest setting. Is it neccessary to put these 'tarps' up/down? If it matter, we live in a 14 years old house, in the middle of the forest, in NE PA. We have a sort of pond/swamp about 75 feet from the back of the house. Also, there were some boxes down there that had very little mold on them.

Thanks for any help or info! Chris

[m Ransley]

Well the moisture season will soon be upon you, no mold on boxes is a good sign things are not to bad but of course you are running a dehumidifier. Did you run it all winter? Below apx 58 is Bad for them. Yes Plastic on the ground will help. But plastic on the ceiling will trap moisture, making a problem. Measure present humidity, then turn off the dehumidifier, measure humidity , put plastic on the floor and see what happens. You realy want it below 65%. Venting is also an option, but then you need full ceiling inslation, not so simple..

[Joseph Meehan]

It depends on the situation. If it is really bad, I think it would be a good idea. However normally on the ground is enough. Use the really heavy plastic and run it part way up the walls.

Even a little mold is a very bad sign.

[Art]

A perimeter foundation drain is the best answer.