No wimpy 5 lb sledge used here. 

Dorothy and I were doing a rebuild of a wall that had been ravaged by rot. We were sistering the floor joists to restore integrity. it was decided to use an old cinder block to put even force along the edge of the 2x12 and prevent damage. As you can see Dorothy does a very good job of working the joist into place. For all you tough guys with your 5 lb sledge, this is the way you do it with a 20 lb cinder block.