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Best Finish for Concrete with Radiant

newinnjnewinnj Member Posts: 19
Any thoughts on concrete floor finishes for a sub basement with radiant heating pex tubing? Thanks for the assistance.

Comments

  • ZmanZman Member Posts: 4,853
    Just concrete, stamped or smooth, will give you the best heat transfer. There are some great finishes out there.
    You can do just about any material and it will work just fine. If you put down carpet, get the high density pad designed for radiant.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • hot_rodhot_rod Member Posts: 11,369
    How nice of a finish are you after. Stamped and colored concrete can look amazing, but there is always the risk of some cracking, even the tiny "road map" cracks.

    Tile or any hard surface is another great match and ideal for low SWT operating conditions.

    Thin, engineered or laminate wood work well also and can be easily changed as they wear or age.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • nibsnibs Member Posts: 236
    We are going with ceramic tile, good heat transfer and low maintenance.
  • nibsnibs Member Posts: 236
    Should have mentioned that it adds to the thermal mass, bonus.
  • newinnjnewinnj Member Posts: 19
    I was thinking of metallic epoxy to get a dimensional look to the floor. I am thinking that should not interfere at all with the radiant.
  • CanuckerCanucker Member Posts: 529
    Metallic paint is used to cut down the radiant output of radiators. I would imagine it will do the same to your floor
    You can have it good, fast or cheap. Pick two
  • hot_rodhot_rod Member Posts: 11,369
    newinnj said:

    I was thinking of metallic epoxy to get a dimensional look to the floor. I am thinking that should not interfere at all with the radiant.


    You should have plenty of surface area with radiant slabs to cover most residential loads, it's a massive radiator, really. I doubt a thin paint coat of any type would put the slab out of output range required.
    The load calc would spell out what is required from the slab in BTU/ sq. ft/ hr. In some cases increasing SWT is required when floor coverings, throw rugs etc limit output.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • How thick is the slab? Any underslab insulation?
    Often wrong, never in doubt.

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  • newinnjnewinnj Member Posts: 19
    I don't have any information on how thick the slab is and if there is any underslab insulation.

    When the contractors come in I will get more information and I will post. There seems to be two types of metallic epoxy. One is using metallic powder and the second using pigments. Stay tuned.
  • Alan (California Radiant) ForbesAlan (California Radiant) Forbes Member Posts: 1,766
    edited May 25
    Are you installing the tubing? Doesn't sound like it.

    If you aren't, you should be talking to the guy that is. Although there's nothing wrong with checking here as well. It's good to call in with all your sources.
    Often wrong, never in doubt.

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  • JUGHNEJUGHNE Member Posts: 5,643
    In our basement we painted the floor.
    First warmed the floor with the tubing, brush wash with mild acid mixture. Rinse well, the heated floor helps the drying.
    Then a base color of floor paint was rolled on.
    After that each room received a variety of color/applications etc.
    If that didn't look good you just try a different Faux pattern until happy. Then apply a clear sealer...no painting changes after this.

    Most important thing is cleaning the raw concrete with the acid.
    Then the sealer at the end.

    This lasted over 20 years with teenage boys doing the typical roughhouse things they do.
  • Concrete is porous. Will the acid affect the tubing?
    Often wrong, never in doubt.

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  • hot_rodhot_rod Member Posts: 11,369
    I have had a number of jobs where they acid etched a finish on the radiant slab. They blend various elements with the acid to get some wild colors. Adding copper graduals get a green color for example.

    I imagine the acid Ph buffers up quickly when it touches the concrete. Possibly safer than some glycols when the Ph plunges inside the tube.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • JUGHNEJUGHNE Member Posts: 5,643
    We scrubbed with brushes, rinsed with clear water and shop vac
    dry repeat maybe 2 more times. This is to clean the concrete to have the paint adhere. When you can rub your hand on the floor and come up with no dust then is considered clean.

    Floor painted in 1995 no problem with tubing.
    BTW which is O2 barrier PB from Infloor.
  • nibsnibs Member Posts: 236
    A bit of topic drift here, as we look up tiling on our radiant concrete floor, we are reading that to minimize edge curl and shrinkage cracking of the slab, we should not start up the radiant for three months.
    They say that heating the slab drives off the moisture too quickly and leads to curl and cracking.
    Thoughts???
  • hot_rodhot_rod Member Posts: 11,369
    there are so many variables to how a slab cures, weather, temperature, wind humidity, the blend, thickness consistency, did they add water at the job site, the way it was finished, etc.

    It's always a good idea to use a cleavage membrane when tiling over a slab.

    https://www.tcnatile.com/faqs/69-cleavage-membrane.html
    Screen Shot 2019-05-26 at 11.48.13 AM.png
    1910 x 1948 - 813K
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • newinnjnewinnj Member Posts: 19
    hi all, the slab and pex tubing is 15 years old. Finally getting around to put a finish on top. I only the owned the property for 8 years so some of the history of the install I am not aware of the details.
  • newinnjnewinnj Member Posts: 19
    Just a quick note the metallic epoxy the metallic part is metallic pigments. The pigment is made from mica. I am going forward with most likely a big box off the shelf product. The commercial grade and commercial install is too expensive per square foot. Dan wrote the definitive history on the metallic paint on rads on this website. Canucker concern is an intresting point. Any info on epoxy can be found on All Garages website. I believe there is mica amount is already in paints. The question is will the amount of mica being used in metallic epoxy will it cut down on the heat. I will give it a whirl and see what happens
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