How can I drill through rim joist/sheathing for a dryer vent?

Question

I want to vent dryer through the rim joist of this home but it looks like this home has some sort of stone sheathing underneath the cedar shake. I can only see it from the basement. I can't really tell from outside without some destructive testing.

I am trying to figure out what this is, poking it with a screwdriver it appears to be hard as stone and would quickly dull my hole saw. The sill plate is atypical too. It looks to be more like a 4x6 with the floor joist notched and resting on it. There is room above this beam for the dryer vent but I don't want to open a can of worms.

The foundation is 24" thick feild stone.

Any idea what I have? Could it just be plaster?

EDIT: Picture attached. I was wrong, there is no room above the beam. Above it you can see the hard material. Either way, I'm not sure I want to drill through the thick sill plate beam now.

Answer 1

Your house is more than likely Balloon Framed. Stick and Platform framing hadn't come into being in 1900. In a balloon-framed house, the studs you see in the basement run all the way up to the roof. The filler material is a concrete mixture that was used as a partial fireblock and also to hold the spacing of the studs.

You can put a hole through the concrete using a 4" coring bit and a coring drill. Google for "coring drills rental" and you find plenty of places that rent them. Your local home center probably does, if they rent tools.