My floor rafters have sunk because of too much weight put on them Stove refrigerator and entertainment center on other side of wall. I have 2x8 16" oc 12 feet long. I am now remodeking Can I jack up these from basement and sister them with 2x6x12? should I try to jack them all up together (10feet)or should I do a few at a time? Can I just lag bolt them together? Thank you Tom