Buying a house w/ possibly burst pipes, please advise

[kw2020]

My wife and I are looking at buying a house that, when the owners moved out, apparently forgot to drain the pipes. The bank hasn't accepted our offer yet (short sale), and the only damage that anybody knows of is:

A. Shower head in the downstairs bathroom popped off
B. An outside faucet apparently broke and was leaking

The water is now shut off. I realize you can't know anything without looking at it, but I just wanted to know how likely it is that there are burst pipes underground or in the house as well, and how extensive the damage could potentially be. The foundation is concrete, so my main concern is that something could have broken underneath the slab. Also, the house has copper piping if that makes a difference.

Thanks in advance for your thoughts.

[havasu]

Alot would depend on where the house is located. I assume it freezes there? Nobody can even guess at what damage might have occurred so I would recommend explaining your concerns to the bank or realtor and possibly get an allowance for any burst pipes, if any.

[phishfood]

In my area, Central Florida, copper piping under concrete slabs, and in walls, for that matter, is notorious for developing pinhole leaks, often in less than 20 years. I have my own theories as to why, and others have theirs.

I don't have any experience with underslab piping in more northerly climes, but I wouldn't think that underslab piping would normally freeze. The outside faucet freezing and leaking, yeah, I could see that, as I have seen it even here in Florida.

Showerhead popping off? That doesn't sound like freeze damage to me. Is vandalism a possibility there?

At any rate, there are some warning signs that you could have waterline damage, so I would definitely keep that in mind when formulating an offer.

[havasu]

I have owned two slab houses so far. One was built with galvanized pipe in the concrete, and the other had galvanized pipe in the attic and walls. The one with the pipes in the attic (which I live in now) was easy to maintain, and was eventually repiped in copper.

If the house in question had copper buried in the slab, I would be cautious for pinhole leaks (which I believe is from leaching lye) but at least it would not be stolen, which is very common with foreclosures on the West Coast.

To easily determine leaks in the pipes, you could place the system under pressure, shut down the flow, wait an hour, and watch for a fall in water pressure with a water pressure gauge attached to one of your valves.

[kw2020]

My understanding is that the pipes under the slab wouldn't necessarily have to be frozen to have been damaged, because the breakage occurs due to water freezing upstream and expanding, forcing a rise in pressure downstream - not radially. I'm thinking this would explain the shower head popping off? The house was vacant and not heated so if it was cold enough to freeze outside, wouldn't everything freeze all the way through? (the coldest it got here was about 2 below zero this last winter). I would doubt vandalism, but it is a good thought. I don't know... just speculating from a layman's standpoint. Good point about the pinhole leaks... I'm sure that is a very real possibility.

Sounds like I will definitely have to test it using pressure as you suggested. Do either of you know, in the event that there is a leak that's determined to be under the slab, what it would entail to fix that? Would the only solution be to jackhammer in and repair it? If so, I'm assuming this would be a pretty involved and expensive undertaking...

Thanks again for the replies.

[havasu]

If a pipe was found to be leaking under the slab, you would have two choices. Either jack out the old concrete and replace the bad pipe, or reroute the line thru the walls and/or attic. Either option is messy, and could get quite expensive, unless you have the time to do it yourself.

To get an idea of how an underslab leak will cause havoc, peruse the lawn and garden section on this forum. Yep, I could have done it myself for lots cheaper, but I had too much going on 261 miles away!

[phishfood]

If you can a pretty good idea where the leak is under the slab, often times the easiest and cheapest way to fix it is to jackhammer a hole in the slab and repair it right there. I have heard of people using stethescopes inserted into small holes drilled through the slab to localize the leak, but I haven't personally tried this. But the most permanent and best method of repair if you start to have leaks under slab is to repipe.

I wouldn't think that the showerhead would be too likely to pop off due to freezing, as any pressure buildup should be relieved through the showerhead itself, not to mention that the pressure shouldn't even reach the showerhead with the shower valve turned off.