I'm trying to rewire part of my house and need access to receptacles on the first floor from the basement. Unfortunately, the space between my foundation wall and subfloor is filled with brick and mortar. It's 100+ year old house and balloon construction. There are one or two spots where the bricks are knocked out and I do see a rim host. Can anyone tell me if it's OK to knock some of the brick out in order to fish wire? Also, what's the purpose of this brick?!!
If the wall studs drop all the way to the mud sill, then the bricks were most likely installed as a fire stop, to keep flames from travelling up into the stud cavities. If I were going to knock them out, I would put something back in to serve the same purpose.