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    Under floor hydronic hydronic radiant heat (29 Posts)

  • Dajack2125 Dajack2125 @ 8:22 PM
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    Under floor hydronic hydronic radiant heat

    Kitchen remodel. We have hot water baseboard heat with a Weil McLain Gold Boiler. I want to remove the baseboard fin tubes in kitchen and utilize entire wall space for base cabinets. Our kitchen is 10 x 15. Completely gutted kitchen, spray on vapor barrier, with fiberglass insulation on all exterior walls. Ripped up subfloor to the joists, and am installing 1/2" plywood with 1/4" cement board on top. Will then be putting ceramic tile down for our new floor. What would be the BEST underfloor hydronic heating system?

    I am quite new to this so if i am doing something incorrectly or if there are better suggestions to accomplish what I need, please feel free.

    Thank you
  • Chris Chris @ 9:02 PM
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    Kitchens and Radiant

    First, need to have a radiant heat loss and design done. Have to take away the floor space square footage of the cabinet areas and any other area where we don't put the tubing such as an island area. This will ensure that we can heat the space with the available floor square footage based on the heat loss and water temperature we need. Used Wirsbo/Uponor QuikTrak for many years with great success.

    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Kitchen Radiant

    The way I would do it:

    1) Like Chris says above, do your heatloss calculations to make sure you can get enough heat from the reduced surface area of the floor although kitchens with all their heat generating appliances need less heat.

    2) Instead of 1/2" plywood, use Uponor Climate Panel with your cement board and tile on top:

    3) And since you have a high temperature heating system, you have to somehow lower the temperature of your water for your radiant system.  You can use a 3-way mixing valve with a pump to do this or you can use a Oventrop Unibox E which reduces temperature by limiting flow:
    Often wrong, never in doubt.
  • NRT_Rob NRT_Rob @ 9:46 AM
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    1/2" plywood

    sounds like you are using 1/2" plywood as your subfloor. I don't think many tile guys would regard that as a very good idea.

    the best underfloor system are extruded aluminum plates. However, you already have a high temp system and depending on your heat loss you may or may not really benefit from a plated system in this case. Generally the answer is yes, but not always. You might skip mixing with a lesser method like suspended tube, but you'd want to be darn sure it was going to work.

    The oventrop box is not a mixing device and should never be used as one. Sending 180 degree water to a plated system would be a bad idea, even if it had an 80+ degree dt across the loop. That would be a grave mis-use of the product. Supply temp and average temp are not the same thing.
  • MikeG MikeG @ 11:35 AM
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    Having done a few ceramic and quarry tile floors, I would caution using anything less than 3/4" for a subfloor.  If possible more is better to decrease deflection and cracking due to loading and thermal stresses.  The Warmboard product may fit this application, subfloor and plates all in one with the cement board and tile over that will give good BTU transfer.  I would check the cement board specs, 1/4" may not be rated for floor use. 
  • Dajack2125 Dajack2125 @ 5:32 PM
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    I looked into warmboard. Seems like a nice product. The problem I have though is trying to get two floors to match up to the same height. I realize that I amy never get them exact, but they at least need to be close. By the time I put warmboard down (1 1/8")
    plus 1/2' cement board + 5/8" for ceramic tile, I am 1 1/2" higher than my dining room and entry way floors. I would dearly love to make this system under the tile instead of under the floor but the differences in the floor heights is to great
  • Chris Chris @ 10:14 PM
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    Here YA Go

    The attached should help and anwser your questions concering QuikTrak
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Dajack2125 Dajack2125 @ 5:18 PM
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    1/2" plywood

    I was a bit skeptical myself when 1/2' plywwood was suggested, but then I received a tip about using a thermal board (Upunor, I believe), and it is only 1/2' thick. I am not sure if that was installed on top of an existing 3/4" subfloor, or nailed directly to the joists.
    This post was edited by an admin on September 1, 2010 5:19 PM.
  • NRT_Rob NRT_Rob @ 5:32 PM
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    that's quik trak or climate panel

    and it requires a full thickness subfloor under it.

    the only thing that is subfloor and tubing media all in one is Warmboard. and I concur that it's the best. it's 1-1/8" thick, though.
  • MikeG MikeG @ 10:44 AM
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    Floor levels

    I've been through the different floor level issue, not with radiant but just doing remodeling and adding an addition to my old farmhouse.  Currently my living room floor of oak is 1.25" lower than my kitchen/dining room oak floor.  I made a custom long tapered transition strip.  Off the other side of the kitchen throough French doors is a family room addition, that maple flooris almost 2" higher than the kitchen floor.  I made a custom transition strip there, but it has some taper and some lip due to the door jamb width.  I didn't want the taper to project out into the kitchen.  I looked at all kinds of ways to keep things level but it wouldn't work.  My wife and I don't even notice it.  You build muscle memory and your subconcience adjusts.  If company comes to visit, people will catch it now and then but they adapt quickly.  No good answers to get the structure and radant both in the floor.  Good luck.
  • NRT_Rob NRT_Rob @ 10:05 AM
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    the title of the thread is "under floor" hydronic.

    you can do it in the joist bay. With heavy plates, it's a pretty high output method. then you just do whatever you need to do for floor height.

    I've lived in a house with a "tripper" step in the middle. I and several house guests almost broke toes before muscle memory kicked in. that was extreme though.. it was a few inches in height differential.

    my current house has 1" to 1-1/2" between several rooms in floor height differential with custom door threshholds like you mention. wouldn't meet code in many places today, but we've never had a problem with them.

    well, except my two year old. when she started running the sudden floor drops would plunk her down pretty fast for awhile ;)
  • Dajack2125 Dajack2125 @ 1:57 PM
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    Heavy plates

    Could you explain what is meant by "heavy plates" ?
  • Dajack2125 Dajack2125 @ 2:36 PM
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    "Under the floor"

    As I was all but convinced that on top of the sub floor would not work because of the differences in floor heights, I changed track and was looking into under the subfloor installation. I was hoping that someone would have had an answer to questions. I have now resigned my self to the idea that if I want to go with hydronic it would have to be under the subfloor.  I have also been looking into electric radiant heat mats, between the subfloor and tile, as they would only raise the floor about 1/8". Any comments?
  • NRT_Rob NRT_Rob @ 2:57 PM
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    heavy plates

    are not flashing grade aluminum but are extruded aluminum. Brand names include Thermofin and Climate Trak (not to be confused with climate panel) among others.

    You have a hydronic system already, so I would rather use heavy plates in the joist than electric mats, typically.
  • Dajack2125 Dajack2125 @ 5:08 PM
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    Under the floor

    How would I go about getting a detailed plan on what I need to do this job. I am told  that I have to step down the temp of the water for the plates, but I need to keep the water at the present temp for the rest of the system. Do I create a separate loop that would feed the kitchen only with its own temp control? 
  • NRT_Rob NRT_Rob @ 5:11 PM
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    in most cases that is what you would need to do.
  • Dajack2125 Dajack2125 @ 5:47 PM
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    "Under the floor"

    This may be a " _____________" question, but here goes.  If I were to go with a staple up heavy plate system, would it help the convection process at all if one was to drill maybe 3/16 to 1/4" holes in the subfloor? Say maybe 6" on center. If it would help, would this cause a weakening of the structural integrity of the subfloor.  (I hope that I am using the correct terminology when I refer to the 3/4 plywood that gets nailed to the floor joists, as the sub floor.)
  • NRT_Rob NRT_Rob @ 5:51 PM
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    nice try

    but no. convection will happen off of the floor surface.

    I should predict this by saying someone needs to do a heat load calculation before you install anything. gotta make sure whatever you do is going to work, after all.
  • Chris Chris @ 8:50 AM
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    Still need to do a heat loss. You would also need to have a seperate zone for the radiant and the water temp would have to be mixied to supply the water temperature needed to overcome the loss. If you are looking for basic idea for cost. Sqft x 1.5 (providing joist are 16" oc) gives you total amount of tubing. Take that number and multiple by .2125 for the amount of plates. Use 3/8" pex. Max loop length to and from the manifold is 250'.
    I would strongly recommend a floor sensor as I stated in a previous post.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Ironman Ironman @ 2:03 PM
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    Let's think about this

    As much as I love doing radiant floor heat, I must ask the question: is it worth it in this situation? You are are only talking about a small area where you are going to loose alot of floor space to cabinets and appliances which will produce heat. Doing radiant floor would be expensive with minimal r.o.i. You would absolutely have to  create a separate low temp zone for the floor with all the apparatus necessary. You cannot run high temp on the floor. Unless you want to replace it in a few months due to failure from heat stress.
    I would recommend using a toe kick heater such as a Beacon Morris "Twin-FloI II". It can run off your present high temp zone or you can zone it separately. My customers have always been pleased with these. They are very quiet and produce plenty of heat.
    Bob Boan

    You can choose to do what you want, but you cannot choose the consequences.
    This post was edited by an admin on September 4, 2010 2:34 PM.
  • NRT_Rob NRT_Rob @ 9:00 AM
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    with all due respect

    you have no idea what temperatures he would need to run in either his baseboard or his radiant floor (especially since he hasn't even chosen a radiant floor method yet), and so your statements about "absolutely" needing anything are a bit premature.

    certainly a load calculation is needed first. but there are many ways to skin this cat, and adding a radiant zone to an existing hot water system is rarely cost prohibitive in a small area. In fact this area would be ideal for radiant in the respect that smaller floor areas mean warmer and more noticeable floor temps. as long as you have enough floor to meet the load.
  • Chris Chris @ 10:10 AM
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    Have to Agree

    I have to agree with Rob. Its a small area and material cost would not be substantia. I also have no problem with him providing the labor to install the plates and tubing as long as he is consulting with a contractor that is going to do the boiler side work. I don't ever recall seeing anything is any of his post concerning looking for a ROI. I think he is more interested in comfort.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Dajack2125 Dajack2125 @ 6:58 PM
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    I agree

    That is true. It is true that I am not really looking for an roi. I want an efficientand affordable methosd in which to heat the kitchen. It is a small room, I already have a boiler, as far as I know (which really is not much)  what I need is  a good staple up system, some way to regulate the water temp, the pex tubing and whatever accessories may be needed. Preliminary cost s for materials seem to be around 1000 - 1500. I think it would be worth the expense for the comfort we would receive.
  • Chris Chris @ 7:03 PM
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    Do Yourself and Us a Favor

    Consulta pro for the boiler work and get a proper radiant heat loss and design for the kitchen. Don't forget the floor sensor either. Best of Luck.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Dajack2125 Dajack2125 @ 7:52 PM
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    Looking for a pro

    I am currently in the process of looking for a reputable pro to do the calcs. Problem is that I live in an area where there are really not a lot of experts on what I want to do. We do have a lot of "experts" but it seems the more I consult with them, the more confused I get. This is one of the reasons I am grateful for you guys in these forums who take the time to answer the questions that are posted

    Much obliged
  • djp djp @ 2:52 PM
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    ceiling radiant

    Have you considered putting in a radiant ceiling? Would use the entire kitchen square footage to heat from above.
  • Mark Eatherton Mark Eatherton @ 9:13 AM
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    MMMMmm yeahhhhh.....

    Warm ceilings AND floors.

    In my professional opinion, ceilings are THE most overlooked opportunities there are for delivering a high degree comfort.

    The floor in my mountain home has radiant ceilings, and as I've said before, at design conditions, the floor runs around 75 degrees F. Comfortable even in bare feet.

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • hwornall hwornall @ 2:10 PM
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    Improving heat transfer with QuickTrak

    I need to improve the heat transfer of 5/16 HePEX tacked to QuickTrak panels. I have a sunroom with a concrete floor, some very skiny sleepers to level the floor, OSB, then QuickTrak, then Pergo flooring.  I have 125 degrees on the intake manifold, and 105 degrees on the output.  the boiler runs for hours and hours, for only 6 degree temp difference.  I'm thinking that tiny aluminum heat sync and the tube of heat transfer "caulk" isn't enough to suck enough heat from the tubes to get past the foam underlayer stuck to the bottom of the Pergo.  I've only got about 1/2 of height to work with.
    1.  other than ripping up the pergo and tiling the floor, what can I add here, that won't break when the floor flexes, but improves heat transfer?
    2.  is there some technique I can use to let more heat percolate up into the room instead of sending hot water back down to the boiler?  like some kind of timer that cycles the boiler on for 10 minutes, andoff for 20 minutes so that the water can sit in the lines and bleed heat?
  • Rich Rich @ 4:28 PM
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    No Insulation

    below the QuikTrak ?  If not it is my opinion that to address this situation you must start over . You have the aluminum at the bottom of the quik trak panel and there is too much downward loss . In short your slab is colder than the air in the room and the part with the wider Delta T will receive more heat transfer . This is unfortunate .  If you have a half inch to play with I would suggest you take the Pergo floor and insulation up nicely , unscrew the Quik Trak and save as much as you can  . use enough self leveling product as is necessary , put 1/2 XPS foam boards on top of the slab , re install the QuikTrak and tubing then re install your floor .  That big cold slab will only steal the heat forever otherwise . Good Luck
    You didn't get what you didn't pay for and it will never be what you thought it would
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