I have a 16 X 11 room that has old hand-hewned log floor joists. They are rotting and two are broke with one end of one down on dirt floor. Existing is rock wall foundation. There is a ledge on one end. The one room cellar this is over is same size. Is there any links to websites that can show me how to replace this floor from joists up. I believe I'm going to have to cut the whole floor out and start fresh but not sure how to start with placement of new floor joists and what size joists I need to purchase. Any suggestions?