TopFeatured.com

I am trying and failing to find a stud on the shared wall of my townhome(the wall between me and my neighbor). I used a stud finder and found studs at 24” apart. Marked my holes and drilled in. It feels like I am hitting something that is not wood or metal. Once through the drywall an inch in I am hitting something. I drilled holes closer in to see how much a have space I have between me and what I’m guessing to be the brick or whatever divides mine and my neighbors house and it’s the same. It seems like there is a small gap between the drywall and what I think is a firewall. I appreciate any advice.