Low basement ceiling issues

[Heath Thomas Jr]

hi all,

Considering purchasing a house that's a 2/1 and making it a 3/2 with a master bed/bath in the basement. It's an older Baltimore home so the basement is unfinished and the ceiling is probably only 6.5 feet at its tallest point. 

Does anyone have experience lowering a basement floor? By the time I add a floor and a finish the ceiling it would be way too small for most buyers. 

[Wayne V.]

Hi Heath,

The prior posts are worth very serious consideration and investigation. Should it be viable however, this is the process for lowering a basement floor, assuming you are far enough away from your neighbors foundations to meet local codes. The process is called "underpinning" and typically requires a building engineer to draw up a plan and a procedure schedule. Underpinning extends the foundation sidewalls below the existing basement floor and provides a new footer for the extended foundation. The foundation perimeter is divided into segments, usually three or four feet long that will be labeled something like A, B, C, D, E. and then repeated. You dig down under these section in sequence, first doing all of the A's, then the B's, C's, D's, and finally the E's, pouring a new footer and then foundation wall extension for each section allowing it to harden thoroughly before proceeding on to the next set of sections. You stop the new pour a few inches below the bottom of the exiting foundation and allow the concrete to set and cure. The final part of the process is to pack non-shrinking grout into that remaining gap between the new foundation pour and the old foundation wall. The reason for the non-shrinking grout is that if you were to pour your new wall all the way up to the old foundation, the contraction of the newly poured concrete wall as it dried would result in settling of the old foundation and therefore settling of the building, and all the bad stuff that causes. Typically doors and windows will bind, floors get wavy, plaster and drywall crack, and so on. After the underpinning is finished, that basement can be excavated and a new concrete floor poured. I would include in floor radiant heat for comfort if you've made it this far. I think it's obvious that this is an expensive process that definitely should be done by professionals. It will require building permits and in order to get them, Architects, engineers, and Inspectors. 

My guess is that besides the complexity and unrecoverable cost of underpinning, that as Brian mentioned, egress, may be the deal breaker. This might be a good one to pass on unless the numbers support a basic fix and flip.