Expert: Stephen Hayes - 2/11/2010

Question
I have a slab that measures 21 ft x 26 ft. It has a garage built on top of it. I want to build a new  garage but on a footing that raises out of the ground 24" to match the house. Adjacent to the slab on the side near the house there is an existing footing that does this for an addition that was never built.  I was told by a couple people that instead of ripping up the slab and footing on the east side that I could instead dig a trench (with a machine) around the 2 other sides(3 but the front is going to be all door) of the slab 4 feet down and 12 inches wide. Then build a earth top form on top of the trench to copy the exisiting 24" wall. This way the ground would act like the forms for the lower 4 feet of concrete and wood would form the upper walls you'd see. I would also run rebar vertically every 2 feet and would have a bonding adjent and rebar to help it bond to the exisiting foundation wall on that one side. I know this isn't the best method but I'm trying to avoid having to rip out everthing and starting over because the cost would be I'm guessing 6-8k more. Would this be safe to build a one story garage on? My thought is the Biggest area of concern is where I would try to join to footings (and local building codes)

Answer
Hi Clinton Brennan;I don't know how your question got to me, but I deal in mainly indoor & outdoor floor coverings such as carpet, vinyl, wood, laminate, etc.  I'm not a construction expert however, I will give you a couple of suggestions.  First make sure you put a ground cover over the ground before any pouring is done.  You don't want moisture seeping up into the concrete.  Next, I would suggest that you 'google' The Concrete Institute.  They are in the Chicago, IL area.  Find their contact information on their website and call it.  Ask for their technical services department to ask your questions.  I do NOT suggest that you talk to 'others' in your area unless they are really great cement contractors who can give you proper advice, and before you take their advice, ask for references of similar constructions to what you want to do, and check those references out to be sure the building owners are happy with the work that was done.

Cordially,

John Michaels