Inaccessable Radiant heating and plumbing problems

[Doug]

A friend of mine has a large (4000 sq.ft.) home built in 1950. It's in New England with a concrete slab on grade construction. There is a small basement under about 10% of the house containing the heating boiler and the beginning of plumbing loops.

The house has radiant heating with copper pipe buried in the concrete. There are also 4 baths and two sink kitchen areas with all supply and drain piping also buried in the concrete.

My friend lost one of the radiant loops about two years ago and heard water sprying out of the loop via a burst pipe under the concrete. The water was geysering out from under the foundation to the outside. She installed a new hydro-air heating system in that part of the building to replace that lost loop. The leaking loop was blocked off and abandoned. The cost was over $17,000 but insurance picked up part of the price. The new system only covers about 1000 sq ft of the home with the remaining radiant loops still heating the rest of the place.

To me the house is a nightmare waiting to happen with most likely frequent plumbing and heating loop failures in the near future with absolutely NO access without jackhammering up the concrete. I'm amazed that the copper has lasted in damp concrete for the 56 years that it has...

Anyone seen a situation like this? So far, we've not even found tradesmen willing to get involved.

I'm tempted to advise her to start a replacement program, jack hammering up pipe runs to each bath, one room at a time. However, most of the flooring has beautiful tiling and she's reluctant to damage that. There's a shallow attic over only part of the house, where they've installed the hydro air system. Due to the almost impossible access I can see why they didn't make the new system more extensive.

My friend is more house rich and cash poor. She has some budget room but it's not unlimited.

Any ideas? I shake my head when I'm in the place wondering what the original builders were thinking.

Doug

[buffalobill]

9-volt battery water alarms are $10 at home depot. it's surprising but our 1910 houses in this area of buffalo ny still have galvanized water pipes in use in parts of the water systems. especially where you have fears, install an electronic water alarm system and a $100 dialer to call your cellphone so you can promptly respond to minimize water damage. in this case the "don't fix it if it ain't broke" may apply due to the budget. the type of heating system to be installed usually will be dependent in part on local energy costs and type of soil, attic versus utility room concerns so the heating system will be indoors in conditioned space, frozen pipe worries, central air conditioning needs, and always some local requirements to meet building codes particular to the address and type of construction and zoning. in the meantime why not suggest a home improvement line of credit application for some confidence on required upcoming repairs. every house is a nightmare waiting to happen, but in the meantime enjoy some sweet dreams with the new alarm system. we've all got to live somewhere. :)

Doug wrote:

[HeatMan]

So, what are you asking? Replacing the radiant or re-plumbing the house?

If there is a question about the re-plumbing, go overhead! Water lines can be run in an attic, you just have to be careful about making sure they are insulated well.

[Doug]

Both - since they are equally problematic.

Perhaps, that's where the hydro-air system was installed. However, most of the house has no attic. This is a Frank Lloyd Wright type of contemporary home, with a tilted flat roof. The attic is under the high part but most of the house has no attic. Most of the walls have floor to ceiling windows so pipes can not be run horizontally across walls without really major rework.

Doug

[Goedjn]

Probably that the house would last a generation or so, after which it's likely to get bulldozed and replaced.

At some point, the roof is going to need to be re-done. That would be an excellent time to put in overhead piping to all the plumbing fixtures. Alternatively, spend a lot of time digging pits in the yard, and drill horizontally under the slab to get pipe runs where you want them.

Which leaves only the radiant floor-heating to worry about.

Annodes would probably extend the life of that system, but in the long run, I think you're (she's) going to have to either abandon it in place, or dig up the floors. If you're lucky, by the time another section fails, someone will have invented a little pipe-crawling robot that will follow all the loops, and epoxy them from the inside. Are the existing pipes big enough that pulling plastic tubing through them is plausible? What would that do to the heat-transfer out of the tubes, and does that really matter?

Hmmm... Flush a wad of cotton pulling a string through a loop. Use the string to pull a cable. Use the cable to pull a reamer (Or somthing that dissolved copper pipe fast.) , then feed plastic tubing, pressurize the tube, squirt (really thin) epoxy in around the OUTSIDE of the tube, depressurize after the epoxy sets, connect the tubing to the heating system. This is do-able. Maybe you'd want to coat the inside of the pathway with long-cure epoxy before pulling the tubing.

--Goedjn

[HeatMan]

Okay.

Build soffits! The don't have to be big, just large enough to run the water lines through. Sounds like your kinda between a rock and a hard place on the radiant system.

[HeatMan]

Anodes? Not quite. The radiant heating pipes are most likely being dissolved from the outside in, most likely by the lime in the concrete mixture.

They are already doing that with drain lines, but these are 4-6 inch pipes.

[e michael brandt]

From personal experience, and info from my contractor father, such leaks are most likely not from the copper interacting with the concrete, but the unfortunate practice, based on their lack of experience 56 years ago, of using iron/steel (non-copper) ties to hold down the piping during installation. This set up galvanic action that eats slowly though the copper... so 56 years later, bingo, you've got a gusher.

It is just possible that, with luck, the rest of the system will remain intact for a good many more years.

emichael

HeatMan wrote:

[HeatMan]

You don't read well, do you?

If you take your time and re-read what I posted, I said "most likely," not THAT WAS THE CAUSE. The lime and fly ash is a more recent additive to nearly all concrete mixes, but could have been an earlier additon to that particular mix.

Let's hope so, but don't hold your breath.

[Doug]

Some interesting ideas...

tnx,

Doug