Hot water Leak in slab

[joec]

Hello, just registered and this is my first post. I have a warm spot under my tile floor that has been there for a few weeks not. I also have noticed that when wwe turn on the hot water in the baths it is like there is an Insta-Hot hooked up. It seems obvious that there must be a leak in the hot water pipe. The pipes from tyhe water heater go up into the attic space, but I am not sure where they drop down.
I just tiled the floors when we moved in in 06. Are there any good alternatives to saw cutting the slab?

Are there ways to determine where exactly the leak is?

Would it help to "buy some time" by shutting off the valve at the water heater when we are not going to be using the hot water, like at night and when we go to work ?
Any advice would be appreciated! JoeC

[Bob NH]

The best way to avoid tearing up the slab is to abandon the pipes in the slab and run all of the water lines through the attic and down through the walls. Do the hot and cold at the same time.

If you have one leak now you will have more later and you will never be done with the leaks.

Do whatever you must for emergencies now since it is costing you a lot of energy to heat the ground under the slab with your water heater. Also, it is conceivable that a lot of water from a big leak could cause more damage.

[Gary Swart]

I have never been able to understand water pipes are buried in a concrete slab. Sooner or later there is bound to be a leak because of the corrosive nature of the concrete with the copper. I know it's done all of the time, but it just seems to me to be idiotic. Now I've had my rant about that, follow Bob H's advice and abandon the buried pipes and repipe either through the attic or somewhere where the pipes will not be subjected to corrosion and are where you can get at them for repairs.

[Mikey]

Bob's advice is spot on. I had a hot-water leak under my slab a couple of years ago, and took to turning off the hot water unless we needed to use it. Isolated the leak to the branch feeding the kitchen, so I rerouted the kitchen overhead immediately, but laid the groundwork for doing the whole house (ran a manifold the length of the house with Ts plumbed in with valves for every fixture) so I could finish it at my leisure. Leisure is just about over -- I'm doing the last room (guest bath) this week.

During the leaky period, I estimated up to 250 gallons per day were lost toward the end. Fill was washed out from under the slab, the slab sunk, and had to be raised via injection of expanding foam. Very impressive and very expensive. The warm spot under the house was very attractive to critters as well, with a couple of families of armadillos under there. Curiously, the electric bill appeared to be unaffected.

Fix it now. By all means shut off the hot water when you aren't using it.

[joec]

Thanks for the replies! I turned down the water pressure and shut of the valve on the water heater for the night! Hope my homeowners insurance covers this ! JoeC

[Mikey]

Hope my homeowners insurance covers this
Good luck. I read my policy and I think repairing that specific leak (and the damage it caused) might be covered, but it's not clear that an entire replumbing "repair" would be covered. Might be up to them to decide how best to "repair" it. Let us know what they say.

[mikept]

I have never been able to understand water pipes are buried in a concrete slab. Sooner or later there is bound to be a leak because of the corrosive nature of the concrete with the copper. I know it's done all of the time, but it just seems to me to be idiotic. Now I've had my rant about that, follow Bob H's advice and abandon the buried pipes and repipe either through the attic or somewhere where the pipes will not be subjected to corrosion and are where you can get at them for repairs.


How about radiant heating pipes?

[hj]

Except in extreme situations, the insurance company will pay to access the pipe and replace the covering, but not the actual repair of the pipe, so if you were to reroute the line they normally will not cover the cost of that.

[jpb116]

So sadly I have first hand experience with this exact type of problem. We had an unsheathed copper pipe in our 1962 ranch slab which leaked. We found out when we had 30% of our living room slab collapse 3 inches, due to the "pumping" of the water down into the ground. Our leak was from a cold water pipe. Many home builders do an inadequate job of tamping the earth prior to pouring the slab, so you have a real serious risk here. Get that after turned off as quickly as possible. We abandoned all the in slab pipes as suggested earlier in this post and ran new lines. PEX made the repairs easier because it needs to be a retro fit to the home unless your going to dig the whole darn thing up. The insurance company covered all the peripheral damage to the home but not the actual pipe problem, which in the end was the least of the bills. Our fix cost $35k, but it doesn't sound like your there yet. There are also methods by which you can drill into the compromised area and inject a filler in there to fill the gap.

[adhaincroi]

I have the same issue right now...its the hot water..have lovely underfloor heating (suddenly)..I have a plumber coming tomorrow..I have a flat roofed house though...no attic to run pipe through..it is stupid as I think the leak is under the kitchen floor about 6 feet into the house..and in my 50s house you can bet your last penny its inside the concrete..would epoxy lining the pipes be a cure??..I work for an engineering firm and we advise it all the time for Commercial purposes...I think I have some serious water issues though..its boggy in Louisiana and the soil around the house is sopping with excess water its actually pooling god knows what the rate of flow is...this frightens the living hoohaa out of me I have to say..and I am the practical one my husband is having a meltdown as he has no plumbing knowledge at all and mine is strictly limited to the bits that come out of the wall except for a basic in how it actually works..I will turn off the water tonight and the gas boiler..maybe it will stem the tide some..thanks for the suggestion..if anyone else has input it would be much appreciated L

[Mikey]

There was another very brief thread on epoxy lining of pipes a while ago:

http://www.terrylove.com/forums/showthread.php?t=21260

I wouldn't waste the money, personally, on a residential supply line. You can locate the leak fairly easily, dig it up a little less easily, and perhaps by looking at the situation you can determine if it's something you're likely to have a lot more of, or not. If not, just repair it and move on. If so, then you've got to re-plumb somehow. Your plumber might have some ideas, and may be looking to buy a new boat. A match made in heaven :D.

[Redwood]

Your plumber might have some ideas, and may be looking to buy a new boat. A match made in heaven :D.

Boat prices are falling as fuel prices rise! LOL
Might be a win-win situation!

[adhaincroi]

Ok the Plumber came actually got two different quotes..I am seriously in the wrong job...two different ideas also...one was to remove the boiler to get to the pipe (why I don't know.. I would remove the drywall on the other side) and run smaller plastic pipe and epoxy through the pipe...the other said go through dry wall in kitchen and reroute pipe through the back of my cabinets and join into the sink...the last one also said "it would depend" (ALOT of times) any way one of his "it would depend's" was to do with if the Kitchen sink feeds the next loop or if the boiler feeds the next loop..apparently sometimes they used to take one to the sink in the kitchen and another to the next fitting...when to be honest I thought they were all looped together on one line so to speak..one jumping for the next...ie: feed from boiler to kitchen sink..then on to the guest bath etc. all in a line can anyone clarify..the house is from the 50s...and to be honest right now at this price theres no way I can afford this repair...I was wondering how hard it would be to do it myself...also am still reading but can I join copper pipe to Pex. ie: (cut wall join pipe run behind cabinet and join back to copper at sink) or do I have to start from the boiler with the pex...like I said more research to be done (so don't think I'm silly)...any input gratefully received...lol never thought I would be plumbing in American (I am Irish)

[Bob NH]

Presumably there aren't any tees under the slab from which other parts of the house are served.

If that is the case, you should be able to find where the under-slab pipe enters and exits the slab.

The question then would be: "How can I get a connection from anywhere on the inlet side of that pipe to anywhere on the other side of that pipe?"

You are in Louisiana, so risk of freezing may be minimal. You may be able to run a line outside at the foundation and in through a wall just above the slab to make the new connection. Another possibility is somewhere in the soffit area where it could be covered with some kind of trim. You could run 1/2" copper high in the toe space at kitchen cabinets.

If the leaky pipe is serving only small-demand uses you might put a small electric water heater on the marooned section and supply it with a cold water pipe, and not replace the hot water pipe.

You can compare those approaches with the job of tearing up the floor and fixing the leak, recognizing that it may not be the last one.

[adhaincroi]

I am not sure if it is likely to T in the wall..(SHE HOPES)..or under the slab...if it is in the wall then I can open the wall at one side of kitchen and run a new line..I may lose an outside faucet but thats ok...only trouble is the rest of the house is after the Kitchen...so if its in the slab....then I have to either open the slab or find a way of getting it over to the first bathroom..I have to then get it to the sink...which means taking up original tile..the bathrooms are tiled in the usual 50" manner..ie all over...was it typical to put the T in teh wall or under the slab...my second plumber also told me that the first one was blowing Smoke up my bum...and that it was too far to do the epoxy pipe in pipe thingy..and that there was no guarantee it would work...to be honest I don't know who to trust...if it T's in wall I will run a new line under the toe kick or in teh cabinets or something..if its in the slab..I love the idea of a new tankless water heater and use the cold supply..but it would be serving 2 showers and 2 sinks..ie bioth my bathrooms...and I think the faucet in the back yard...beginning to wish I had learned to be a plumber instead of a Singer...

[Bob NH]

It goes into the slab somewhere, and it comes out somewhere. It doesn't tee under the slab unless there is a third place it is coming out of the slab. You need to find where you can cut and cap the pipe so you can abandon all the hot water lines in the slab.

You don't have to find the exact place it enters or leaves the slab; but you must find a place before or at the first branch away from the slab entry or exit. That is the place to cut the line and either cap or make the bypass connection.

Do you have a gas or an electric water heater? If electric, it is pretty simple, and very little energy penalty, to add another at a convenient place on the other side of the abandoned line. Electric instant heaters are not practical.

[adhaincroi]

Ok after much dry wall removal I have found where my hot water comes out of the boiler and goes into my house...it comes out of the boiler and goes straight into the slab floor...it then comes out at various places in the house each time just a pipe out of the floor...no T's no joins or junctions or whatever you want to call them...one pipe in and one pipe out at various sites in the house...its either all ringed together or it T's under the floor...I know everyone says don't dig the floor up..but I have a flat roof...back to back showers...and pretty much no way to reroute other than complete remodel of most of the house..(that I was just about to put on the market)...One plumber had told me he could put pex and epoxy down the line therefore lining the inside of the pipe...and fix the leak that way..and that would result in a little loss in water pressure I'm not sure how though..now that I know it goes straight into the floor..I know Pex doesn't do a 90 degree angle...any body got any ideas...I am really tempted to carefully remove the concrete and fix it at the leak...looks like the copper pipe is newer than the rest...the cold pipes are all galvanised where they come out of the boiler and change to copper near the fixtures...I am at a standstill...Thanks L

[Mikey]

Don't despair yet -- you're on the right track. As Bob said, your plumbing likely has no joints under the slab. The lines loop up at each fixture location and are joined above the slab to allow connecting the fixture and continuing the line on to the next fixture. If there's only one line going into the slab at the boiler, it's a linear array down the line. Some more complicated configurations exist, but are rarely found unless it's custom construction.

The next task is to figure out what sequence the fixtures are in, and then determine which under-slab link the failure occurs in. The first task is the harder of the two, but not impossible. It's all easier than it sounds -- sort of -- especially on the hot-water side. We'll do the second part first.

With all the above-slab junctions exposed, just turn off the hot water at the boiler and go to bed (I said this would be easy). First thing in the morning, turn on the hot water again, have a cup of coffee, and relax for a few minutes to allow some hot water to flow from the boiler to the leak -- but DON'T draw any hot water from any fixture. Then go feel every hot-water junction. If you're lucky, some will be hot, and some will be cold. The leg between the last "hot" and the first "cold" in the line is the leg in which the leak occurs. If there are no hot junctions, the leak is in the first leg.

The problem is determining the order in which all the junctions occur on the line, but this can usually be accomplished using a little common sense and some more touchy-feely technology. Turn off the hot water at the boiler and let hot line cool down -- overnight is good. Then gather your friends and family together and have each person grab a "hot" junction at each point where the pipes come out of the slab. Then turn on the hot water at the last fixture on the line (the last point in the line, of course, is where a pipe comes out but no pipe goes back down). Then turn on the hot water at the boiler. Have each person yell out when his pipe gets hot, and mark the order in which they yell on your diagram (you DO have a diagram, right?).

Now you know the layout of the line, and the leg in which the leak occurs. It's an easy plumbing job to replace that leg with new pipe, but routing the new pipe may be anything from trivial to a real bear of a job. But at least you've got a real handle on what you need to do.

Of course, that will fix only one leak, and as Bob said waaay back there,

"If you have one leak now you will have more later and you will never be done with the leaks."

Keep in mind, of course, that most real estate law requires that you disclose any condition that might materially affect the value of the house. If you fix just one leak, and sell the house, you are probably obligated to disclose your fix at the time of sale. Whether you're obligated to tell the buyer that a bunch of experts have cautioned that more leaks will almost certainly follow I can't say. It's at least a "spirit of the law" thing, IMHO.

Keep us posted.

[adhaincroi]

(The lines loop up at each fixture location and are joined above the slab to allow connecting the fixture and continuing the line on to the next fixture.)

So far only thing near any fixtures is the actual water feed..no loops no coming up and going down or on to the next..just one pipe coming out of the slab..if I want to find out the order and I hold the line coming out of the slab surely nothing will happen unless request water at the faucet???..there is no joint..by the house lay out..last in line are the sink and shower in master bath before that I think the guest bath..but I cant get at pipes in the showers at all..its all tiled and they are hidden in wall..hence the re-plumbing problem...even the local recommended plumber sucked air over his teeth on this one and said he'd send his boss/owner out... I have added an image maybe it will clarify my dilemma..but I doubt it lol..by the way I really do appreciate all the help..and I don't want this to be a bodge job..goodness knows there were a few when we bought the house that I have slowly been fixing..Thanks L

[Mikey]

Bummer. That implies joints and fittings under the slab, which I'm told is a no-no here. I think it's back to chopping up the floor and fixing the leak itself. If you're lucky, you will find something like a pipe damaged during installation, or a rock in the fill that it was mashed up against the pipe or something else pointing to a specific failure. Then you can fix the leak, repair the floor, and live happily ever after. If you just find a badly corroded pipe that looks like it might all be that way, then replumbing is your only option, and not a very attractive one, it would seem.

I have heard of folks burrowing under their slab and fixing the problem from below, but I can't imagine doing that. Maybe a house mover could jack it up and then set it down in the same place after the repair or replumbing, but that sounds expensive, unless you get one who charges only by the mile :D.

[adhaincroi]

The whole joints under the slab thing is probably not the way they would like it here either..my husband did point out though that in Louisiana almost all the houses were raised until about the 50's and it was easier to get at plumbing..he thinks maybe this was done on automatic..not thinking some poor schlub was going to have to dig to get to pipes...it looks like I am out this weekend to get a concrete digging device...fingers crossed..I presume Home Depot will know what I need and be able to rent it to me...I tore some of the floor up last night trying to see if I could find it I think I have it narrowed down..and a shiny new sharpy X markes the spot lol...

[Mikey]

You can jackhammer it or cut it. Both are very messy jobs -- the saw is much worse. When I had a floor safe installed in Miami, though, they just beat the hell out of the floor with a sledge, and it eventually broke up enough to pull out the pieces. It'll probably cost a couple bucks to rent a power tool like a Hilti jackhammer or a 12" masonry saw, so I'd try the beat-on-it technique first. Out in the center of the floor, it's probably only 4" thick. Don't go overboard and crush the pipes.

[adhaincroi]

Ok couldnt do it last weekend so this weekend is ON..I rented a Hilti drill (Ar Ar Ar loved it) to put large bolts into the floor for my new drywall is the jack hammer a lot bigger (I am only 5ft and upper body strength is typically girly lol)..nice to know I have aprox 4 inches to work with..I do have a sledge but not sure if I have sufficient strength to make much impact...husband is stronger but less controlled and not good with tools..how much damage can he do if I let him have a go first and then do the more delicate closer in stuff myself??...lol then my only issue when I find the pipe is if i can fix it...I have never actually braised/welded/sweated (whatever its called) copper pipe that had to hold water before...maybe call plumber after I find the leak and point him to it...what do you lovely gentlemen think??..oh and any ladies who may be out there...no being sexist here lol

[Mikey]

Wish I were there to watch this! Be sure to get pictures of yourself in action...

John Henry, Oh John Henry,
John Henry was taken sick,
And Polly drove steel like a man,
Lawd, Lawd, and Polly drove steel like a man.

[adhaincroi]

Sounds ominous..lol..I will get some pics I promise..am actually quite looking forward to getting a go at the concrete mangling machine...in a sort of sick and scary way it should be fun..this will be the first time I have chopped up the actual floor..I am sure for husband panic factor it will rank up with the time I chopped a hole in the house (for a doggie door) and the time I cut around all the furniture in the lounge to get the carpet up (furniture too heavy to move husband at work ergo: cut around furniture)...I am sure we will go to Husband panic factor Amber Alert at least...I might even manage to get him to Red lol...poor love he didnt really realize what marrying an Irish woman would do to him...anyway will most likely not fix it this weekend..am going to dig it up and find it..I hope...will take some pics for you to peruse..then will make plan of action...

[Redwood]

When I cut into a slab I usually use a Skil Saw with a diamond blade which I spray with water from a spray bottle to keep the dust in a mud form... It doesn't take a lot of water to do that with the slower blade speed of the Skil Saw and I'm not running it in a puddle of water for safety reasons...

After scoreing the line as deep as the Skil Saw can cut I then commence to whacking the center of the cut area with a sledge hammer. Pick out the rubble and you have a nice hole with very little mess.

[adhaincroi]

MMM sounds good...It was mentioned earlier that the pipes should be 4 inches down at least..so I suppose I don't run the risk of Skil sawing straight through them..or am I being Naive here lol...also by Skil saw do you mean a circular saw...(sorry am British)...and a plant spray bottle I presume for the dust..I like this idea it wont make a huge mess..also inhaling concrete dust probs wont be great for my asthma...and like you say after scoring the sledge hammer will be more manageable (girlyness wise)

[Redwood]

Yep, by saying Skil Saw I do mean circular saw...

On a history side note here... Many times people say Skil Saw no matter what the brand name is... The first electric powered circular saw was invented by Edmund Michel of Louisiana who founded the Michel Electric Hand Saw Company Inc. which later evolved into Skilsaw.

That is why on a job site today if you ask a buddy to pass you the Skil Saw he just might reach down and pick up a Millwaukee circular saw and hand it to you...:D

The Skil Saw wil not go deep enough to cut all the way through the slab and should not reach the pipes. You should set the plant sprayer bottle to a straight stream and have your hubby spritz a little water at the leading edge of the blade keeping the dust in a mud form.

The cut at the surface will be neat and square while below the edge of the cut it will be jagged and promote better bonding of the concrete patch. You need to use a bonding agent on the edge when you pour the patch.

[adhaincroi]

OK CHECK..concrete bonding agent..will ask at home depot or do research online..as for the Skil saw thing...its the same in the UK..Hilti means Hammer drill..lol...Dear Mr. Edmund probably forsaw (no pun intended) the Skil saw's uses if Louisianians insist on putting the damn pipes and joints in the Slab...