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Is this a staple up hack job?

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srandall
srandall Member Posts: 4

Hi,

I’m a homeowner who has learned a lot from this forum already so thank you for all the expertise shared. Please forgive my ignorance that may show through below!


We bought a 2,400 sq ft 1840s home, heated with baseboard heat. We are doing a fairly extensive reno and addition and decided to use hydronic radiant in the places we can, since everything is torn apart. The majority will be staple up between floor joists, a small section will use a board like Warmboard on top of the subfloor, and we’d like to run tubes in the new garage’s concrete.

A heating company that claimed to have a lot of radiant experience started installing a portion of the staple up yesterday. I am concerned about quite a few things (photos attached):

  1. The installer said the loops can be of varying lengths (all under 300’) because the manifold valves will have adjustable flow meters. Is this a common practice? My understanding was that the loops should be all similar lengths to prevent flow differences.
  2. There is no slack in the tubes and the curves are quite tight. Where the pex (1/2”) goes through the joists, it’s pulled very tight - I’m concerned that expansion will cause rubbing noise between the tube and joist. (The holes are 1.25”.) Valid concern or no?
  3. Where they cut the heat transfer plates, they left very sharp edges - will this damage the pex over time as it moves?
  4. The heat transfer plates are anywhere between 4” apart and 10” apart (end to end), just randomly put up. The flooring above this will be 3/4” wood subfloor with vinyl plank on top. Not a super thick floor covering but in a retro like this where we’re confined by the existing layout, I would think putting the plates as close together as possible (2”?) would be preferred.
  5. The supply line is set in about 1’ from the interior wall, so by the time the loop is straight enough for a heat transfer plate, it’s in 3.5’ from the interior wall. This seems like a complete waste of potential heating space. Is there a reason for starting them in so far?
  6. Upon first inspection, there are three places (probably more) where I can feel a kink. Is this reason to be concerned?

Basically I’m wondering if this is all standard practice and I’m overthinking, or if I’m getting a hack job? Thank you very much in advance!

Comments

  • Alan (California Radiant) Forbes
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    Not a hack job, but there could have been more attention to detail. There should be more slack to allow for expansion and contraction, no sharp edges at the ends of the plates, the plates should be closer and there should be no kinking whatsoever.

    Others will chime in.

    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
    Mad Dog_2SlamDunksrandall
  • hot_rod
    hot_rod Member Posts: 22,353
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    it does look like the tube is pulled to tightly at the ends of the runs, you want to allow some movement

    Fasten plates at least every 12” or less

    Plates should not touch the joists on the sides as the will expand some, possibly squeak.

    Yes you need to clean any burr whrn the plates are cut. Are they extruded or stamped plates?

    Certainly no kinks allowed!

    The more aluminum in contact the better

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    srandall
  • Ironman
    Ironman Member Posts: 7,385
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    I would be even more concerned with whether the radiant floor can produce enough heat for a 1840 house.

    Was a Manual J heat loss calculation done to determine what the actual heat loss of each room is and to know if the floor can provide enough for each one?

    How about a radiant design and layout? Or, are they just assuming that putting up tubing in every joist bay is sufficient?

    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    kcoppMad Dog_2LRCCBJsrandall
  • srandall
    srandall Member Posts: 4
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    Thank you for the fast replies! I can’t tell you how much I appreciate your knowledge.

    Ironman, all good questions. We have been asking the installer for both a quote and a layout/design for a month, haven’t received anything, and then he showed up Friday and just started installing. So now we’re trying to figure out what to say to him Monday. We will have mini splits in some rooms for a/c and can use them as supplemental heat, but I’d like to minimize that. And would feel a lot better knowing that some math has been done that shows that 90% of the time, the radiant will be enough heat (we’re in upstate NY for reference). I’m assuming no design has been made, because the first circuit they made they just kept going until they used up the 300’ roll, and the second circuit will be about 150’ long. I’m wondering why they didn’t make both circuits 225’, or maybe that’s not important?


    I also should have said, while the house is 1840 it was completely gutted in 1980 so the insulation is all fiberglass (most exterior walls are only 4” thick though so only R11). Anywhere that we are gutting we’re making them 6” so we can increase R value.

    My husband and I could do a lot of the install work ourselves but would like a LoopCAD design made first to reassure me that the radiant will be enough most days. Any ideas of how to find someone who can design the layout and calculate heat loss, etc for us?


    Last question for now…when you all say “no kinks” - does that mean reshape them with a heat gun, or splice them, or start over completely?

    Thank you!

  • srandall
    srandall Member Posts: 4
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    Sorry, I forgot to answer hot_rod’s question. I’m pretty confident they are stamped. I know you’ve mentioned in other threads you much prefer extruded. Is that due to them being thicker and therefore better heat transfer?

  • DCContrarian
    DCContrarian Member Posts: 200
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    @srandall , reading your post from 10:13 this sounds like a recipe for disaster. Things that begin badly usually end badly. Before he does any more work you need to have a frank discussion with this guy. As in, he needs to stop and give you a quote. No more work until you come to agreement on pricing.

    If he really is just installing blind I'd be very worried, the odds of ending up with a satisfactory system that way are low.

    Here are some back-of-the-envelope calculations you can do. First, if you have a heating history, follow the procedure in this article to estimate your overall heating load: https://www.greenbuildingadvisor.com/article/replacing-a-furnace-or-boiler

    The thing about heated floors is the output is entirely determined by the floor temperature. The rule of thumb is that you get two BTU's per hour per square foot for every degree of difference between the floor and the room. So if the floor is at 90F and the room is at 70F that's 20 degrees of difference so you get 40 BTU/hr per square foot. Floors don't usually run hotter than 90F because they start getting uncomfortable underfoot, it's probably safe to assume a floor temperature of 85F, so 30 BTU/hr/sf.

    If you follow the steps in the article you'll get a total house heating load in BTU/hr. The first sanity check is to take that number and divide by 30, that's how many square feet of heated floor you need. Compare that to the actual house layout and see if that's even achievable.

    The tricky part of the design is whether a surface temperature of 85F is consistently achievable. This is where some of the workmanship issues that you've noticed come in. Gaps in the plates, plates not tight to the floor, plates spaced too far, all of that is going to lead to cooler spot in the floor. And you can't make up for the cooler spots by having other spots hotter, you still need to walk on this floor. If you have plenty of square footage you can get away with cold spots, but if you're tight this is going to cause problems.

    srandall
  • hot_rod
    hot_rod Member Posts: 22,353
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    type A pex can be heated to remove kinks what type heat pex do you have?

    What about floor coverings? Hard surfaces are best for radiant

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    srandall
  • Ironman
    Ironman Member Posts: 7,385
    edited May 20
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    The fact that he didn’t even quote a price, let alone write a contract, is a huge red flag! You need to stop him from doing anything more until you have a contract, a load calculation, a design and layout, and a performance guarantee that the system will sufficiently heat the house. You should also confirm that he’s licensed and insured.

    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    srandall
  • srandall
    srandall Member Posts: 4
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    Thank you, everyone, for your help. When we brought up some of our concerns today, the installer said he’d come pick up his materials that he installed and then hung up, which I think is best for all of us. It was incredibly helpful to have your input to reassure us that we weren’t being overly picky about the lack of planning and quality of workmanship. I know you all are busy and don’t have to answer questions from complete strangers like me, so thank you again!

  • ethicalpaul
    ethicalpaul Member Posts: 5,757
    edited May 21
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    I'm not here to beat up on your contractor, but I think they could do things a little better.

    For a data point for you, here is the staple up (not really staple up because I screwed the extruded plates to the underside of the floor—so it's more of a screw up haha) that I did in my house. I like the extruded plates because I think they make a better connection to the floor/subfloor. I even wonder if there is a thermal transfer paste or material that could make the transfer even better.

    This is the first time I had touched this kind of plate, the first time I ran pex to it. I'm a computer programmer who is handy, I'm not a radiant flooring person. I think it looks pretty good though. I had read about this kind of system on this forum before I attempted it. I knew not to "stretch" the pex, but rather to leave room for it to expand/contract. It's not exactly a high-skill operation.

    In your case, I'm more concerned about the things that others brought up—is there enough heat flow here to actually heat your rooms? Also, seeing how they installed the plates and the pex, I wonder what kind of job they did on the flow manifold and circulator stuff.

    See the photos here:

    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
    Ironman
  • bmma
    bmma Member Posts: 36
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    As others have said, get a written quote/contract before you allow him to do any more work. The written contract is to protect you and him. It should clearly define the work to be done, the materials to be used, schedule, and cost. I deal with contracts all the time in my professional life and I can't stress this enough, it really does protect both parties in the event of an issue.

    Ironman
  • Zman
    Zman Member Posts: 7,588
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    What kind of tubing did they use? Do you have a picture of the box or a logo on the tubing? I have never seen tubing that looks like that that is made for a heating system.

    The tight turns and lack of bushing where the tubing goes through the joist would be my next concern.

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    Alan (California Radiant) ForbesIronman
  • PRR
    PRR Member Posts: 158
    edited May 23
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    I even wonder if there is a thermal transfer paste or material that could make the transfer even better.

    For to-metal, to-ceramic, or to loaded epoxy (CPUs), yes, obviously. Because the job is small, some geeks really over-do it, with polishing plates and Silver grease for 2% better conductivity.

    To wood, a poor conductor, a gap filler leaves 90% of the thermal resistance in the path.

    Since you are generally coming down from 600+ degree fire, a few degree drop across this gap is the least of your losses.

  • ethicalpaul
    ethicalpaul Member Posts: 5,757
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    You lost me regarding coming down from a 600+ degree fire…

    I am talking about the air gap that is going to exist between the aluminum plates and many parts of the underside of the floor. Air is a worse conductor than wood of course so maximizing the contact between the metal plates and the rough wood surface seems reasonable.

    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
  • kcopp
    kcopp Member Posts: 4,446
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    Looks like Viega hePex to me. It does have an O2 barrier.