I live in a house that I can hang pictures on the interior walls, but if I try and put a nail in an outer wall, I can't. I assume that means my walls use some type of infill.
In order to hang stuff on the walls, I need to know what I'm drilling into.
I see a yellow plaster wall from the inside and a red brick from the outside. How do I determine what's in between them?
I hope that these answers can apply to other people. My situation is a house in the midwest built in the late 1920's with an unfinished basement with concrete walls all the way up to the first floor. The brick starts at the bottom of the first floor which is 3' in the air.