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Community and Q&A

Repairing hydronic floor heat leak in concrete

user-1052275 | Posted in Mechanicals on

I have a 1953 home with hydronic floor heating that was abandoned in 2006 due to leakage. I have been looking for a product that may help and I think I have finally found one but can not find anyone with experience in the English-speaking world to help….

The system is iron pipe (or maybe mild steel) in concrete floor slab-on-grade construction with two zones. I have removed the furnace and pumps to make room in the utility room but would love to revive the system if possible. I always thought that a good de-scaling product followed by an aerobic sealer of some sort –like fix-a-flat for pipes may do the trick.

My brother is currently stationed in Austria and his landlord had some plumbers come over to do some repairs to an old hydronic system with radiators in a 100+ year old building and they pumped this goop into the lines for 6-7 hours to seal them and then purged the lines. he took a picture of the stuff they had and it was from a company called BaCoGa

Anyone have experience with this stuff?

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  1. GBA Editor
    Martin Holladay | | #1

    I have never had any experience with BCG TD.

    However, here's some advice: if you have iron pipes or steel pipes embedded in your slab, you should abandon the hydronic distribution system. Whatever trick you devise to try to plug the rusting pipes won't be worth the trouble.

  2. user-1052275 | | #2

    Hi Martin,

    Are you suggesting that spending $200-$300 for materials and fittings and spending a couple of days trying this is not worth the time because:

    1) It won't fix the leak(s) ?
    2) The repair will fail in short order making whatever boiler and other equipment I purchase a total waste?
    3) Other ?

    The guys using this stuff in Austria told my brother that they had been using it for years with good results. Does anyone in the US have experience with this or similar products?

    Would it change your mind if it were determined that the pipes were in a bed of sand or gravel below the concrete rather than in the concrete itself? ---I have not done any exploration to determine if this is the case or not but I have found that this house was built during a time when these kinds of experiments were taking place in order to make the systems more serviceable....

    Best regards,

  3. davidmeiland | | #3

    I suggest you post your question on That's the place to get a lot of input on a radiant question.

  4. heidner | | #4

    Josh, one of the problems you may run into is that the pipes had been abandoned - air allowed into the pipes may have accelarated damage resulting in many leaks and weak points. Any carpet or floor covering will cover possible leaks -- and you would need to expose the floor. The sealing may require multiple attempts over a long period of time. It also sounds like the maintenance history of the system while it was in use is also unknown... This may be a long term science projects.

    You didn't say which climate zone you live in... but if it is a cooler/colder climate - and you are trying to use the hydronic heating - you may discover one of the reasons it was abandoned is because of the heat loss to the ground. The $300 in materials may be insignificant compared to the $$ paid to heat the ground -- and water that might be moving through the sand and gravel..... Long term a better solution might be to seal the floor, add layer of insulation on top of it -- and move to mini-splits for heat. Your climate and location makes a big difference...

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