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Best Finish for Concrete with Radiant

newinnjnewinnj Posts: 21Member
Any thoughts on concrete floor finishes for a sub basement with radiant heating pex tubing? Thanks for the assistance.

Comments

  • ZmanZman Posts: 4,973Member
    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 Posts: 11,618Member
    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 Posts: 308Member
    We are going with ceramic tile, good heat transfer and low maintenance.
  • nibsnibs Posts: 308Member
    Should have mentioned that it adds to the thermal mass, bonus.
  • newinnjnewinnj Posts: 21Member
    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 Posts: 534Member
    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 Posts: 11,618Member
    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.

    Click here to learn more about this contractor.
  • newinnjnewinnj Posts: 21Member
    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.
  • 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 Posts: 5,715Member
    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 Posts: 11,618Member
    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 Posts: 5,715Member
    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 Posts: 308Member
    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 Posts: 11,618Member
    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
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • newinnjnewinnj Posts: 21Member
    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 Posts: 21Member
    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
  • newinnjnewinnj Posts: 21Member
    Hi All, The basement floor is finished. I went through 8 boxes of the epoxy. Each box had small container the size of a face lotion container that had the metallic flakes. The plastic jar lid was probably heavier than the flakes. I called the company and they get this call all the time since a lot people have radiant floors in their garages. There is no issue they said. This specific material works best under 80 F and low humidity. It seems during application of the paint, not running the radiant will be better for it. If you have questions about the floor please email me since that will be considered off topic. Now I have a question to the forum. I have three zones and one to the basement. That is one pex line going to the space under the stairs. There the pex line goes to a manifold and is split into four lines. The four lines returns back and they go to another manifold and back to one pex line back to the main return. The lines that go to the floor do not look like pex. I have included pics and wanted everyone's opinion on the setup. I don't know what I have and is it setup properly. Thanks for the help.
  • nibsnibs Posts: 308Member
    Don't think there is any problem with the Onix tubing, but is it clamped directly to copper pipe?
    Also the soldering looks worse than mine, and at 76 yrs of age, my hand just is not steady enough to do neat solder joints.
  • newinnjnewinnj Posts: 21Member
    hi nibs,

    It sure looks like its clamped directly to the cooper. I think my tech term was incorrect. One pex tube that goes to the copper split. I don't know what to call that. I called it a manifold. The pic does not show it well but there are two copper splits on top of each other. Just tell me what to look for and I can take a look again. In short yes it looks like it is a direct clamp.
  • hot_rodhot_rod Posts: 11,618Member
    those are probably brass street adapters that are soldered inside the copper fitting, that was the most common Onix adapter

    without labels it’s hard to know which loop is which
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
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