Expert: Bruce E. Johnson - 10/5/2011

Question
I am adding a two story addition to our very old farm house. The addition foundation and floor are level, however we decided to tear down what would have been a "transition area" which was a bedroom that was probably added on later, which has a cistern below.  The concrete foundation has since sagged, and in one corner cracked. How do I match up the level addition floor to the existing crooked foundation. There is about a ten foot span over the cistern,high going corner to corner. Can I sister onto the old cement or should I put some kind of other support to get things level? HELP!

Answer
Hi Roger, it's hard to say exactly what your best solution is without seeing the problem.  From what you say there is a ten foot span that you need a new floor on? How about just building a wood joist floor to span from the new foundation over to the existing original house foundation?  This can be accomplished with 2x10 joists.  Lag bolt a ledger to each "good" wall and hang the joists on Simpson joist hangers.I hope this info helps please feel free to write again regarding this or other matters, sincerely Bruce Johnson..bejohnsonconsulting.com