Buying a house with in slab copper piping

Questions on how we spend our money and our time - consumer goods and services, home and vehicle, leisure and recreational activities
Post Reply
Topic Author
allenflmz
Posts: 4
Joined: Sun Oct 06, 2019 6:06 pm

Buying a house with in slab copper piping

Post by allenflmz » Sun Oct 06, 2019 6:59 pm

My wife and I have been house hunting in a HCOL area, and we finally had an offer of ours accepted on a 1960s slab on grade ranch.

We just did a home inspection and discovered that the house has water supply pipes, and radiant floor heating with copper pipes imbedded in the concrete slab foundation original to the house. When the house was built in, it was common to imbed bare copper pipe in concrete. Over time, the contact with concrete corrodes the pipe and leaks develop, typically before 50 years, which has past several years ago. No signs of leaks are visible and the water and heating systems appear to be working perfectly.

Has anyone experienced this situation before in a house? Is a leak imminent in future or could we continue to have no problems for years or decades to come?

We otherwise really like the house.

Here are our options:
1. Walk away from the deal. We would be only be out what we paid for the inspection.
2. Buy the house anyway and preventatively reroute the water pipes and replace the heating system. A ballpark cost to do this seems to be about 20k in our area.
3. Buy the house and live in it. Repair when a leak develops.

A previous buyer had already backed out of the deal for the same reason after asking for a 20k reduction and being rejected by the sellers. The sellers seem to be willing offer a small reduction on our accepted price, but are unwilling to reduce further due to the systems being in good working condition.

drawpoker
Posts: 2521
Joined: Mon May 19, 2014 6:33 pm
Location: Delmarva

Re: Buying a house with in slab copper piping

Post by drawpoker » Sun Oct 06, 2019 7:39 pm

Are you absolutely certain the pipes were not wrapped in sleeves? My house is not circa '60's but 1979 and built on slab.
Because of this potential problem - with the otherwise workhorse copper water supply pipes - many builders used the sleeves (esp. around the very vulnerable joints) to prevent contact with any rocky material in the soil.
Is there any way you can check this?

Big Dog
Posts: 1444
Joined: Mon Sep 07, 2015 4:12 pm

Re: Buying a house with in slab copper piping

Post by Big Dog » Sun Oct 06, 2019 7:53 pm

Radiant floor heating is extremely efficient. Since the heat rises from the floor, you can keep the thermometer lower than you otherwise would. If it ain't broke, don't fix it.

meebers
Posts: 327
Joined: Sat Apr 14, 2012 7:20 pm
Location: Florida

Re: Buying a house with in slab copper piping

Post by meebers » Sun Oct 06, 2019 8:09 pm

It was a problem for me here in Florida. House was 19 years old when I discovered that the water supply copper pipes were eaten away from inside and became razor thin. I had to do a re-piping with the new lines in the attic. Plumber told me he did plumbing and not drywall. Drywall had to have slots cut in it to be able to run the new flex plumbing to all the fixtures. Outside faucets had to be trenched and, in my case, block wall had to be busted out to fit the new faucets. In doing so, the sprinkler wires, sprinkler pipes and telephone and cable were cut. Over the years I always had a "discussion" with the phone company guy who liked to ground his telephone equipment to my copper plumbing. Each time after he left, I would cut the ground wire. He should have drove a ground stake and connected to that and leave my pipes alone. :P I did not have radiant floor heating. YMMV

KeepinItPositive
Posts: 20
Joined: Sat Mar 18, 2017 9:46 am

Re: Buying a house with in slab copper piping

Post by KeepinItPositive » Sun Oct 06, 2019 8:31 pm

A few years ago I stumbled across a really helpful forum for radiant and other hvac questions at heatinghelp.com

There are a lot of pros on that give generously of their time for questions like this.

Topic Author
allenflmz
Posts: 4
Joined: Sun Oct 06, 2019 6:06 pm

Re: Buying a house with in slab copper piping

Post by allenflmz » Sun Oct 06, 2019 8:38 pm

drawpoker wrote:
Sun Oct 06, 2019 7:39 pm
Are you absolutely certain the pipes were not wrapped in sleeves? My house is not circa '60's but 1979 and built on slab.
Because of this potential problem - with the otherwise workhorse copper water supply pipes - many builders used the sleeves (esp. around the very vulnerable joints) to prevent contact with any rocky material in the soil.
Is there any way you can check this?
My understanding is that it was a common method of construction in the area at the time. Other houses in the area have replaced the heating systems. I wonder if there being no problem to date implies that the pipes were wrapped or some other more robust way of construction?

curmudgeon
Posts: 1866
Joined: Thu Jun 20, 2013 11:00 pm

Re: Buying a house with in slab copper piping

Post by curmudgeon » Sun Oct 06, 2019 8:39 pm

Sounds like a bay area Eichler (though I suppose it could be something else as well). Personally, I wouldn't reject the house over the piping, though I would keep the issue in mind, and possibly redo things if other work were being done. While the Eichlers have some good features, I've always avoided them myself because they are very inflexible when it comes to retrofitting or updating (no attic or crawl space to run wiring/piping. If you have to cut slabs, or run conduit on the roof, it makes more mess and/or awkward appearance (it all can be dealt with, but at a cost).

User avatar
LadyGeek
Site Admin
Posts: 57010
Joined: Sat Dec 20, 2008 5:34 pm
Location: Philadelphia
Contact:

Re: Buying a house with in slab copper piping

Post by LadyGeek » Sun Oct 06, 2019 8:48 pm

This thread is now in the Personal Consumer Issues forum (house).

allenflmz, Welcome! You are asking (1) what are your options and (2) how to fix the piping. We'll answer both questions, but the majority of the discussion is about the pipes and heating - hence the move to the consumer issues forum.
Wiki To some, the glass is half full. To others, the glass is half empty. To an engineer, it's twice the size it needs to be.

BogleBoogie
Posts: 643
Joined: Tue May 13, 2014 11:15 am
Location: AK

Re: Buying a house with in slab copper piping

Post by BogleBoogie » Sun Oct 06, 2019 9:19 pm

If you love the house and it is a fair deal, pay the 20K and have peace of mind for another 50+ years. Also, it adds to the value of the home so it isn't like you are setting 20K on fire.

BuddyJet
Posts: 169
Joined: Mon Jun 24, 2019 8:56 pm

Re: Buying a house with in slab copper piping

Post by BuddyJet » Sun Oct 06, 2019 9:32 pm

Copper in slab is very common in the Dallas area. I have had minor leaks repaired by using a leak detection service to locate leak then going into slab to repair. While I have not used them, there is also a process to coat the pipes with epoxy to prevent further leaks and avoid busting slab.

I wouldn’t walk on just that issue but would if it was galvanized pipe in the slab. I ran across that issue in Houston.

muddgirl
Posts: 62
Joined: Wed Aug 17, 2016 1:33 pm

Re: Buying a house with in slab copper piping

Post by muddgirl » Sun Oct 06, 2019 9:39 pm

Our house in Texas had in-slab piping, the house was maybe 20 years old when we bought it. We had two leaks on the same service loop in 4 years - should have re-routed after the first leak but the plumber didn't present that as an option before repair. We rerouted after the second leak. Incidentally our home insurance paid for repair of both leaks, because I had asked for an additional rider that apparently covered leaks. But of course our rates went through the roof and when we sold the house the buyers complained and made a lot of noise about not being able to get affordable insurance.

After some google searching I convinced myself that the copper piping weakened due to the lack of water softener (water in that part of Texas is very hard) + service companies grounding their equipment to our copper piping, but it's been nearly 6 years so I can't recall what led me to that conclusion.

User avatar
Sandtrap
Posts: 8377
Joined: Sat Nov 26, 2016 6:32 pm
Location: Hawaii No Ka Oi , N. Arizona

Re: Buying a house with in slab copper piping

Post by Sandtrap » Sun Oct 06, 2019 9:51 pm

#3
I have seen and worked with commercial and residential properties with copper lines in the slab, block walls, etc, that have not had problems for many years. Some buildings were quite dated.
You may not have problems, ever.
But. . . then again. . .

j
Wiki Bogleheads Wiki: Everything You Need to Know

User avatar
Cubicle
Posts: 40
Joined: Sun Sep 22, 2019 1:43 am

Re: Buying a house with in slab copper piping

Post by Cubicle » Sun Oct 06, 2019 11:22 pm

I also vote not to walk away over it. You can always fix it later. And, unless I'm misunderstanding, its only on the ground level. So a leak probably wouldn't cause catastrophic damage inside the house before you could get to it.

muddgirl
Posts: 62
Joined: Wed Aug 17, 2016 1:33 pm

Re: Buying a house with in slab copper piping

Post by muddgirl » Mon Oct 07, 2019 12:51 am

Yes, I should add that in our case, the primary damage was to the laminate flooring + tile, not a hugely expensive fix in our area. And if I could go back in time I would not walk away from that house due to the issue (it's impossible to find a house without in-slab plumbing in the neighborhood we wanted to live in) but I would have paid to reroute after the first leak instead of doing the cheaper fix.

IowaFarmBoy
Posts: 696
Joined: Fri Jan 22, 2010 8:19 am

Re: Buying a house with in slab copper piping

Post by IowaFarmBoy » Mon Oct 07, 2019 5:39 am

When I was building houses in Texas in the 80s this was standard practice and had been for years. Radiant floor heat pretty much wasn't done there so I am only talking about supply lines.

One clarification- most of the copper is actually under the concrete and in the fill sand (at least at the time I was building.) In locations where it would be in contact with concrete we were required to slip a plastic sleeve over it so that the concrete would not be in contact with it. These sleeves would be needed where the copper came up through the slab and where it crossed the deeper concrete reinforcing beams (but I think it was usually under the beams, too). All joints and fittings had to be above the slab.

I don't know if they had used sleeves since the start of slab construction or if that was a later development. I haven't heard of corrosion being an issue but it seems like it could be over time. It seems like the issues would primarily be where the copper comes up through the concrete.

stan1
Posts: 7426
Joined: Mon Oct 08, 2007 4:35 pm

Re: Buying a house with in slab copper piping

Post by stan1 » Mon Oct 07, 2019 7:15 am

There are millions of houses and condos between California and Texas that have copper piping under slab foundations. PEX tubing started to replace copper only about 10 years ago. You can pay someone to blow an epoxy coating through the lines but it may cost more to do that than to repair a minor slab leak.

Topic Author
allenflmz
Posts: 4
Joined: Sun Oct 06, 2019 6:06 pm

Re: Buying a house with in slab copper piping

Post by allenflmz » Mon Oct 07, 2019 8:21 am

The issue is that the copper pipes seem to be cast in the slab bare with no sleeves. In the decades after the 60s people started wrapping the pipes in sleeves, then transitioned to plastic pipes in concrete.

Thanks for all the replies. We're leaning toward option 3 right now.

User avatar
Sandtrap
Posts: 8377
Joined: Sat Nov 26, 2016 6:32 pm
Location: Hawaii No Ka Oi , N. Arizona

Re: Buying a house with in slab copper piping

Post by Sandtrap » Mon Oct 07, 2019 8:50 am

allenflmz wrote:
Mon Oct 07, 2019 8:21 am
The issue is that the copper pipes seem to be cast in the slab bare with no sleeves. In the decades after the 60s people started wrapping the pipes in sleeves, then transitioned to plastic pipes in concrete.

Thanks for all the replies. We're leaning toward option 3 right now.
Hope it works out for you.
Thanks for the follow up.
j :happy
Wiki Bogleheads Wiki: Everything You Need to Know

stan1
Posts: 7426
Joined: Mon Oct 08, 2007 4:35 pm

Re: Buying a house with in slab copper piping

Post by stan1 » Mon Oct 07, 2019 8:58 am

allenflmz wrote:
Mon Oct 07, 2019 8:21 am
The issue is that the copper pipes seem to be cast in the slab bare with no sleeves. In the decades after the 60s people started wrapping the pipes in sleeves, then transitioned to plastic pipes in concrete.

Thanks for all the replies. We're leaning toward option 3 right now.
There are multiple failure modes. One is water chemistry inside the copper pipe which a sleeve won't protect against. I think you are fine with #3.

batpot
Posts: 838
Joined: Thu Jul 11, 2013 8:48 pm

Re: Buying a house with in slab copper piping

Post by batpot » Mon Oct 07, 2019 12:36 pm

Option 3a:
Negotiate reduced sales price based on them not being sleeved.
Put the money towards a whole house reverse osmosis system.

ScaledWheel
Posts: 71
Joined: Sat Jul 23, 2011 8:06 pm

Re: Buying a house with in slab copper piping

Post by ScaledWheel » Mon Oct 07, 2019 12:40 pm

Wife and I bought a house with copper pipe in slab running to the radiators in the finished basement. We did not realize this at the time and they ended up leaking (or were leaking before we bought it). We rerouted through drop ceiling which saved money but still ended up being costly. I don't think it's worth walking away from but there's a decent chance that someday they will need to be replaced/re-routed. I would lean towards trying to get a small reduction in the price, or maybe seeing if there's a home warranty that would cover the system that they can prepay for a period of a few years to cover the risk.

chw
Posts: 690
Joined: Thu May 24, 2012 4:22 pm

Re: Buying a house with in slab copper piping

Post by chw » Mon Oct 07, 2019 12:56 pm

It’s not a matter of if, but when leaks will develop. I live in an area where this type of construction was common in the 1960s, and it’s very common for geysers to erupt in the slab during heating season.

I would get 3 quotes to see how much it costs for the supply line and buried plumbing to be updated to current code. It won’t be cheap, as walls will have to be penetrated in order to get plumbing above grade.

You could save some $$ on the heating portion of the retrofit by installing duct work for a hvac setup that would provide AC/heat (via heat pump). Ranch style homes generally are easier to duct, so perhaps this is an option. Going this route would only require plumbing to be updated to the kitchen and baths.

No way would I buy this unless the Seller was picking up most of the cost of the plumbing update.

ddurrett896
Posts: 1089
Joined: Wed Nov 05, 2014 3:23 pm

Re: Buying a house with in slab copper piping

Post by ddurrett896 » Mon Oct 07, 2019 1:59 pm

I wouldn't buy a slab home.

Leaks are a nightmare and a slab amplifies it. I've seen to make homes get torn apart to replace a leak or faulty drain. I'm talking all new flooring, kitchen remove, etc.

StillLearning1977
Posts: 74
Joined: Tue Feb 27, 2018 6:30 pm

Re: Buying a house with in slab copper piping

Post by StillLearning1977 » Mon Oct 07, 2019 3:19 pm

My house cast iron pipes in slab. Slowly degraded and finally collapsed causing serious flooding in house, which was a blessing in disguise b/c triggered coverage under homeowner's policy.

Paid $6000 deductible. Without insurance, would have cost $20,000+ between the repairs & digging/cutting through slab to fix the pipes.

drawpoker
Posts: 2521
Joined: Mon May 19, 2014 6:33 pm
Location: Delmarva

Re: Buying a house with in slab copper piping

Post by drawpoker » Mon Oct 07, 2019 3:29 pm

stan1 wrote:
Mon Oct 07, 2019 8:58 am

There are multiple failure modes. One is water chemistry inside the copper pipe which a sleeve won't protect against....
That isn't considered a risk for houses on city water. It is acknowledged as a potential for a problem for people with well water with high mineral content. High magnesium especially.

OP, is this house on city water or out in the country?

RedDog
Posts: 52
Joined: Sat Dec 05, 2015 4:36 pm

Re: Buying a house with in slab copper piping

Post by RedDog » Mon Oct 07, 2019 3:51 pm

stan1 wrote:
Mon Oct 07, 2019 7:15 am
There are millions of houses and condos between California and Texas that have copper piping under slab foundations. PEX tubing started to replace copper only about 10 years ago. You can pay someone to blow an epoxy coating through the lines but it may cost more to do that than to repair a minor slab leak.
I'm starting to see new built homes in my area (mid-South) using a PEX like system routed in the ceilings and walls. Might be a good option for retrofitting slab plumbing.

Topic Author
allenflmz
Posts: 4
Joined: Sun Oct 06, 2019 6:06 pm

Re: Buying a house with in slab copper piping

Post by allenflmz » Tue Oct 08, 2019 9:22 am

The house is on city water.

Mr. Rumples
Posts: 159
Joined: Sun Aug 25, 2019 7:16 am

Re: Buying a house with in slab copper piping

Post by Mr. Rumples » Tue Oct 08, 2019 9:49 am

There is no perfect material for pipes, each has advantages and disadvantages. Regarding PEX, the verdict is out on whether its safe for drinking water. It can take decades for problems to surface or an unforeseen event to show new issues such as the release of benzene by plastic water pipes during the during the fires in northern California in 2018. Apparently, mice to like to nibble on PEX. PEX can also soak up organics from the soil. During the 2014 Elk River chemical spill which left 300,000 people in WV without drinking water, some homes with plastic pipes had to have their plumbing replaced since decontamination was not possible.

Valuethinker
Posts: 38828
Joined: Fri May 11, 2007 11:07 am

Re: Buying a house with in slab copper piping

Post by Valuethinker » Tue Oct 08, 2019 9:59 am

allenflmz wrote:
Sun Oct 06, 2019 6:59 pm
My wife and I have been house hunting in a HCOL area, and we finally had an offer of ours accepted on a 1960s slab on grade ranch.

We just did a home inspection and discovered that the house has water supply pipes, and radiant floor heating with copper pipes imbedded in the concrete slab foundation original to the house. When the house was built in, it was common to imbed bare copper pipe in concrete. Over time, the contact with concrete corrodes the pipe and leaks develop, typically before 50 years, which has past several years ago. No signs of leaks are visible and the water and heating systems appear to be working perfectly.

Has anyone experienced this situation before in a house? Is a leak imminent in future or could we continue to have no problems for years or decades to come?

We otherwise really like the house.

Here are our options:
1. Walk away from the deal. We would be only be out what we paid for the inspection.
2. Buy the house anyway and preventatively reroute the water pipes and replace the heating system. A ballpark cost to do this seems to be about 20k in our area.
3. Buy the house and live in it. Repair when a leak develops.

A previous buyer had already backed out of the deal for the same reason after asking for a 20k reduction and being rejected by the sellers. The sellers seem to be willing offer a small reduction on our accepted price, but are unwilling to reduce further due to the systems being in good working condition.
It is a HCOL area and presumably good houses are in short supply -- good houses meaning in the right location?

Am I right that the $20k is a "rounding error" on the total price of the house? It's absolutely true that that is a Behavioural Finance classic mistake - 2% it may only be, but $20k is still $20k.

I'd eat the $20k (or try to get the seller to allow $10k for it) and install a new system (Option 2). I happen to dislike hot air intensely due to dust and dryness, so I'd go for rads ("hydronic" in American?). But of course if you can dual it with the AC ducts that may provide a considerable savings.

That's better than the risk of 3 - of significant water damage - a leak in a slab could go on for a long time without you knowing (might, in fact, already be going on) - only way to detect it would be an unexplained drop in water pressure. Also any future buyer will worry about 3.

If you think there are other houses you can buy then 1 is also a viable option.

CurlyDave
Posts: 1238
Joined: Thu Jul 28, 2016 11:37 am

Re: Buying a house with in slab copper piping

Post by CurlyDave » Tue Oct 08, 2019 10:21 am

allenflmz wrote:
Mon Oct 07, 2019 8:21 am
The issue is that the copper pipes seem to be cast in the slab bare with no sleeves. In the decades after the 60s people started wrapping the pipes in sleeves, then transitioned to plastic pipes in concrete.

Thanks for all the replies. We're leaning toward option 3 right now.
That is the option I would choose. It could outlast you, but if you have a prudent EF you will be fine if it goes.

If you have a leak in the radiant heating pipes the amount of leakage is limited by the amount of liquid in the system plumbing, and you will know about the leak because the liquid level in the system will drop. A leak in a water supply line is a different animal and could be much greater in volume.

If there is ever a problem, get a large number of bids for repair. Not every contractor is going to be able to think outside the box on this kind of repair.

drawpoker
Posts: 2521
Joined: Mon May 19, 2014 6:33 pm
Location: Delmarva

Re: Buying a house with in slab copper piping

Post by drawpoker » Tue Oct 08, 2019 10:44 am

Valuethinker wrote:
Tue Oct 08, 2019 9:59 am

- a leak in a slab could go on for a long time without you knowing (might, in fact, already be going on) - only way to detect it would be an unexplained drop in water pressure........
Not so. A big spike in the water bill would be a good indicator. OP posted the house is on city, not well, water.

batpot
Posts: 838
Joined: Thu Jul 11, 2013 8:48 pm

Re: Buying a house with in slab copper piping

Post by batpot » Tue Oct 08, 2019 11:41 am

I'd also suggest getting one of these:
viewtopic.php?f=11&t=289609

msk
Posts: 1342
Joined: Mon Aug 15, 2016 10:40 am

Re: Buying a house with in slab copper piping

Post by msk » Tue Oct 08, 2019 12:56 pm

Sounds like a total replacement would cost "noise" $ hence it should not enter the decision making prominently. All pipes leak eventually. You replace when they need replacing. The replacement will simply start deteriorating sooner rather than later. I had a bunch of pipeline engineers working for me. Oil. We did all the good stuff in looking after our billion $ network. And they still leaked. Over the decades the technology for anti-corrosion measures improved. At any time when a pipeline section needed replacement my engineers would say "This time it will last 30+ years". but until I retired, those pipelines had to be replaced in 20. Don't rush into premature replacing. It's like a road. Whenever you resurface the road, the lifetime of the new surface starts wearing and gets consumed from Day 1. You save a lot if Day 1 is 5 years into the future... You may even end up selling the house before a replacement is imperative.

yakk0
Posts: 23
Joined: Mon Nov 27, 2017 4:41 pm

Re: Buying a house with in slab copper piping

Post by yakk0 » Tue Oct 08, 2019 6:25 pm

Is the house part of a tract built at the same time? Can you or your realtor find out if neighbors have had leaks?

My friend whose house was built around 1980 had their copper pipes leak a couple years ago, and a large number of their neighbors had the same happen to them within the year. There was a plumber's truck somewhere on the street every week for months. This was in SoCal and judging from the responses here, soil and water conditions will affect how long they copper survives.

If you do buy and don't choose to fix it immediately, just be mindful of signs of leaks. In my friend's case, it was a particularly warm tile in the kitchen where hot water was leaking underneath (non-intentional radiant floor heating haha).

bigmac86
Posts: 2
Joined: Thu Dec 13, 2018 3:31 pm

Re: Buying a house with in slab copper piping

Post by bigmac86 » Tue Oct 08, 2019 9:10 pm

Look into the Copperknight (copperknight.com) company who makes a system that prevents pin hole leaks in copper lines caused by hard water. For a 4000 sq.ft. house cost about $1000 . Lots of home owners in Texas hill country use the system.

Post Reply