Expert: Bruce E. Johnson - 4/16/2009

Question
I live in Buffalo NY.I have plans to build a 24x30 two story garage (2nd story storage only) Is it acceptable to use a monolithic concrete slab for a building this size,in this area. If not what would you suggest

Answer
Hi Dan, in this area where you have the potential for ground freeze it might not be possible to build any kind of building on a monolithic slab. Your local building department may be able to answer that question more specifically.  I am a big proponent of mono slabs but haven't built any in the frozen north...Chances are that you will need to do a concrete stem wall foundation with the footings 3-4 feet below grade.  What you can do is fill inside the foundation and cap it with a slab or do a basement foundation.  The reason most structures in your area have basements is because of the frost line.  If you are going to dig down several feet to do a stem wall foundation then why not dig down another couple of feet and make it a basement.  However, if you are doing a garage, then you might not want to do an elevated structural slab, so a stem wall foundation is probably your best bet.  I hope this information helps feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com