My basement wall is concrete block. I believe the blocks are 8H X 16L X 12. The sill plate (not sure that is the correct term) is probably a 2X8 and only covers a portion of the top of the blocks. The core holes in the block are therefore open to the basement. Should they be covered or left open?
Is there any disadvantage to covering them? I was thinking of using treated 2X4's that I can slip under the floor joists. That would the holes, but doesn't overhang the block.
The basement is quite dry, but in Summer, there is a slight "wet" or earthy smell. I am wondering whether covering the core holes would help? Also, it is a farm house, and giving less places for mice to hide might be an advantage.
I would plug them, but I am not 100% sure. It seems logical that you will have conductive looping going on in them, robbing you of heat. Blocking and sealing them would sure help that. As for the smell, that, to me, means an outside issue. Do all the normal and easy things, like grading, making sure gutters/etc are working properly, drainage gravel, etc. If the stink is still there, then excavate and fix the water issue. Stink, to me, means water, and that only means trouble; mold, etc.