Another Vent in the Wall

Now here's an odd problem I've never heard anyone mention before...

Last week, I noticed a problem with condensation on the wall between our garage and our dining room. Wasn't sure what could cause such an odd problem in one very small area along a sixteen-foot wall--but when I touched the wall, I realized that the area where the condensation was occurring was very, very cold--twenty or more degrees cooler than the rest of the wall. I went in the house and discovered that the wall in the dining room was also very cool--but there was no condensation because that wall was in a climate-controlled area where humidity was much lower. The cold area was only a foot or so wide, but it extended several feet up the wall, warming gradually.

Our AC repair people are sending someone out to take a look tomorrow, but I think I know what the problem is: I am pretty sure that the builder and his contractor ran a flexible duct into the wall in the dining room, intending to put in a vent--and then forgot the vent. As a result, the AC and heat are blowing into a space between the walls, with no way for the air to escape. This summer has been so humid that the condensation has begun to form on the very cold wall.

I'm going to call the builder tomorrow as well. While the house isn't under warranty any longer (we bought it in 1996), this isn't a typical warranty issue. I think we all presume that the builder is keeping up with where the flexible duct tubing has been run and is subseqently ensuring that vents are installed there.

The frustrating thing is that I suspect this will pretty much guarantee they're going to have to cut into walls, replace wallboard, etc., and that's more of a mess than I really wanted to have to deal with--but it'll have to be done, I'm pretty sure.

I'll let you know what the A/C guy and the builder have to say about the problem...