I suspect the hot water pipe is leaking. Water vapor will seek out
cooler surfaces to condense.

On 5 Jun 2005 11:45:27 -0700, "R8EDXXX" wrote:

Yesterday I noticed that paint was peeling in my kitchen downstairs. I
took a good section of it off and noticed that the drywall was moist
and dark in color due to humidity. I decided to replace the drywall
but when I took it off ants were swarming underneath. There must have
been 1000's inside the wall because they loved the humidity. I removed
them and the insulation inside the wall. There are also three copper
pipes which run vertically behind the drywall I removed. I noticed that
the two hot water pipes which were insulated with foam were wet and
that's where the water was coming from. I removed the foam insulation
and one was completely wet on the inside while the other was only
partially wet. I checked the pipes for leaks but did not notice any
while it was uncovered. I bought new insulaiton for the pipes and
covered them both. Within a timespan of 2 minutes the one of the hot
water pipes once again contained condensaiton after it was covered. Is
it normal for copper pipes to sweat, however did this not occur while
the pipe was not covered with the foam insualtion. Can I patch up a
new piece of drywall without insulating the pipes or what is going on.
As far as I know, the insulation is only to keep the pipes insualted
for the hot water. I live in CA so I'm wondering if I should not
insulate them if years from now it will be humidity inside the wall
again. Thank you in advance for your help and advice.