What is the best way to tell a water stain on a drywall is wet

Question

We had a leak in the roof a while ago that caused water stains on the wall. The leak should be fixed now, but we wanted to wait a bit before painting the wall until we are sure that there is no more water leaking in. I feel that it is now really hard to tell if the wall is wet where the old stain is, or just cold.

What is the best way to tell if the drywall is actually moist or if it is dry. Preferably without buying any moisture meter or so.

Thanks Simon

Answer 1

The simple method in the previous answer, blotting with a paper towel, is certainly simple enough and ought to work if it's wet enough.

If you need a more precise measurement, you can use a moisture meter:

These are most often used to see how dry wood is, but they work in sheetrock too. There are expensive ones and inexpensive ones available at big box stores, hardware stores, etc. An inexpensive one is probably good enough for what you need to do.

Answer 2

Press a paper towel firmly against the wall and hold it there for a minute. Then feel the paper towel for see if you sense dampness in the paper towel.

Hand the paper towel to somebody with neutral hands, since yours may now be cool, to sense if the paper towel is damp.