I have a quick question about building foundations. We are doing a large addition to our turn of the century home. We are digging out a full basement and using 12 in. masonry block. Does this block need to be filled with concrete????
Ask your local building inspection officials first. Local seismic, soil, and other design and code considerations can drive the decision. Generally the answer is 'no', but checking locally with the authorities is the best way to proceed.