I'm looking at a house tomorrow thats on a slab, not a foundation. 

i read that this can potentially be a problem if the plumbing is under the slab.

how big of a disadvantage is it to buy a slab house? 

has anyone here had problems with one?

thanks!

I don't really understand the question.  If the house is on a slab, how is that not a foundation?

Meaning it has a concrete slab, not a basement (or crawl space)? 

I have one of those and never really thought about the plumbing, sure hope nothing is under the slab!!! Maybe someone with more construction experience could weigh in as to whether it might be possible to find where the plumbing is most likely running based on what would be visible around the mechanicals?

One thing I realized is that the concrete slab is colder in the winter -- I think my HVAC guy indicated that this is not so great for heating bills.

I know here in Florida, All of the houses are on slabs and yes the plumbing almost always runs through the slab. It can be a problem for a remodel simply because you have to keep the plumbing where it is or bust up and replace the concrete (potentially very expensive). 

@Nancy Larcom  OK, I can understand from that perspective.  I live in central Texas and pretty much none of our houses have basements.  So, houses on a slab are the typical thing.  I have built MANY over the years.  As far as the plumbing, it is actually ran in the sand base under the concrete up until the point that it turns upward to go through the slab and into the house.

@James Stevens  and @Mike Flowers What if something breaks?? I guess the slab has to be jackhammered up to fix it? Well I sure hope I never have to worry about that. In my case the structure was actually a carriage house that was rehabbed as a 2 bedroom, so plumbing at some point must have been added to the existing structure.... 

You are correct there.  If a pipe breaks under the slab, it will have to be jackhammered up to repair it.  

yes, if there is a pipe burst or even crack, you have to break up the slab to repair it and refill it after. but, this is the least of your worries if that happens. The flood damage will be more expensive to fix than the pipe.

@Marci Stein  

Every home I have ever lived or owned in my entire life has been on a slab.  I've never had a problem.  Yes, you may have to break up the concrete if there is a plumbing issue, but it's rare.  

Lol, ok, I'll try not to add to my list of things to worry about!

Slabs are not so typical here, but old houses and plumbing issues are... However I'm sure (or am going to assume) that my carriage house was converted recently and will have no problems! And all our old basements have their own problems, like moisture and mold.

(Not "our" as in mine personally, but as in Philly's old basements. Mine are all in decent shape thankfully!)

You can fix pipes without digging into the slab.  Here's a neat little video that describes everything you want to know about it, including a rough cost. 

Although, I also have not encountered problems with pipes under monolithic slabs on ground (which IS a foundation, by the way).

I've had a couple houses where we had pipes burst under the slab and were able to reroute new supply lines from the source (hot water heater) to the affected fixtures.  Then just abandon the line under the slab.

Not always possible, but there are certainly times when you don't need to dig up a slab to fix the plumbing.