I have a house built in the 50's and the garage is attached to the house. The garage slab is poured but the 3 outer garage walls actually sit on what I believe to be 2x4's One board between the house and garage entrance door rotted away and I could see basically what looked like cinder blocks stacked about 2 ft down. I could stick a pole right down the center of them. I'd like to replace these boards around the three walls and I'm not sure how to do it or what to replace them with. Any Ideas?