damp dry wall living room- help!

I have a townhouse and my living room wall is shared with my neighbors wall. I have some floating shelves on this wall, one day they fell over. While inspecting the issue, I notice that the wall anchors for the shelves were damp, then to my surprise I was able to pull the anchors out by hand because the area around it was moist. Something behind this wall is definitely wet. But I'm far from the kitchen and bathroom. I have no idea where or how to find this leak, and it can possibly be from my neighbor.

where do I start to address this issue???

Sounds like a roof leak, who is responsible for the outside envelope? Water can travel great distances, call your insurance company.

Interior wall, exterior wall, elevated roof line above the leak? Any Windows above?

Oh, to House Repair Talk!

I'd agree with Neal. I've owned two townhouses with different common wall construction methods. The first used a 2x6 plate top and bottom of each wall. Then they used 2x4's for the studs, with studs 24" on center for each side of the wall, so my drywall wasn't hung on the same studs as my neighbors drywall. Insulation was put in between the studs. They also had a double layer of drywall on both sides. It was a very effective sound barrier and firewall between the units. There were no penetrations for electricity or plumbing in the common walls. The other one used 2x4 framing for each unit separated by a 1" or 1.5" thick piece of gypsum board as the firewall. These walls had plumbing and electrical in them and they were insulated and drywalled as a normal wall. These too were very effective as a sound barrier and firewall. Some townhouses have used concrete block as common walls, though their ability to act as a sound barrier is pretty poor. I could hold a conversation through the concrete block basement walls in my first unit with my neighbor. When I finished the basement in mine and helped my neighbor finish his we studded out the walls and insulated them. Which shut off that communications path.

So in looking at your unit, how are the walls constructed and do they contain any plumbing lines? If there isn't any plumbing roof leaks either from the shingles or flashing along the common wall are the most likely causes. Interior humidity would need to be at sauna like conditions for the drywall to be that damp from humidity.

Have you checked to crawlspace for openings through the floor into that wall? Moisture could be moving by inside due to the stack effect and wetting the warm walls.

Gary
PS. Welcome!

I haven't found any crawl space...These town homes are old and built with most walls sharing. I looked in both room closets and don't see anything. Hmm roof leak? It has not rained in a long time. I'm in southern California. It's an interior wall no windows. I"m sure the other side of this wall is also my neighbors living room or similar room. I've added some pictures so you guys can see. You can see my long floating shelf and one of my 3 big shelves is on the floor. Literally fell off the wall one day. Its a pretty long wall, I have a picture with the hallway that leads to the kitchen. I also tried to take a picture from top of stairs so you can see entire living room, nothing close to this wall has water from what I can see anyways. But you're right, water can travel anywhere. I guess I can start by contacting the HOA

Oh and THANKS for the welcome!!! You guys sound like you know your stuff!!!

Have you talked to people on the other side of the wall.

If your AC evaporator is in the attic, you may want to check the drain line for a blockage.