Expert: Dan Griffin - 9/30/2008

Question
I'm considering the purchase of a mid-century home that has a suspended concrete floor.  From the basement looking up, I noticed the bottom of the first floor is comprised of many concrete beams spanning lenghtwise and set about two feet apart, with some kind of black-colored hard panels between the beams.  The beams appear to span 20' or more without any other support.  I'm told the main floor, second floor, and ceiling have a similar structure.  The floors also have radiant heat (copper in slab).

I assume this is a pre-cast beam system of some kind supporting a poured concrete floor.  But it seems unusual to me to find this sort of thing in a 1950's residence.  I'm wondering if there is any history of problems with these types of floors, or whether there is anything special to look for in an inspection.  

Thanks for any advice,
John

Answer
John, I am not familiar with this type of residential floor system.  I have not ever heard any scare stories about it either.  Concrete beams are subject to tension cracking in the bottom.  They can have hairline cracks, get worried if there are lots of them close together or if they are more than hairlines.  I wish I could share more information with you, but again, just no mileage.