In many older homes, floor joists sag, the result of inferior, hollow Lally columns that have deteriorated and no longer provide the necessary floor support. Author Emanuel Silva, a restoration and remodeling carpenter in the Boston area, has replaced many such columns, and in this article he shows how he did it in one particular home. He began by jacking up the beam just enough so that he could remove the old column. The basement slab was thin, and the existing footing was little more than stones thrown in a hole, so he punched an opening through the slab, dug down, and poured a new concrete footing. Because the basement had moisture problems, he decided to build a pier to raise the column above the floor. Step-by-step instructions and detailed photos make this a thorough guide to replacing a Lally column.