Using a Thermal Break for a basement heated floor - Recommendations from NuHeat

Discussion in 'Shower & Bathtub Forum & Blog' started by johnfrwhipple, May 1, 2014.

  1. johnfrwhipple

    johnfrwhipple Bathroom Design & Build - North Vancouver, B.C.

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    This week I have been asked by a fellow out in Winnipeg to help design his basement walk in shower. It's a large room and will feature a walk in barrier free shower. The basement is a full height one and the frost level in Winnipeg is a good 5' deep. The first hurdle in this design was incorporating a thermal break under the heating wire. The second hurdle will be designing a proper capillary break at the doorway!

    I made a bunch of phone calls and emails last couple days and have decided to do some "Garage Style" testing with two products recommended to me by NuHeat.

    #1) Easy Mat from Custom Building Products (peel and stick version)

    and

    #2) AcoustiCork from AcousticCork USA

    My Winnipeg client has made a few inquires and two tile outfits in Winnipeg have boycotted the use of cork. Also I believe it was Flex-Therm did not like the idea of cork either. The peel and stick Easy Mat looks appealing for this job. It came with a primer and is not affected by moisture so we can use it, cover it and forget about it.

    The basement slab has been altered and needs some repairs. I have suggested we treat the slab as a starting point and that we build up at least 1.5" above the installed mat. At this thickness the Easy Mat is acting like a slip joint kind of separating the new mortar bed from the old basement floor. With a room this size there will be elevations of roughly 2.25" at the perimeter.

    Are there any other options in Thermal Breaks not mentioned here? Nuheat also recommended a product called Cerazorb. Not heard of that one before.

    JW

    www.No-Curb.com - my blog site on Barrier Free, No Curb, No Dam and Hobless Showers​

    (604) 506-6792 jfrwhipple@gmail.com
    Last edited: Oct 30, 2014
  2. johnfrwhipple

    johnfrwhipple Bathroom Design & Build - North Vancouver, B.C.

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    Drain Options for this Build

    The client has ordered a linear drain from Noble Company for his project. We will be installing the Noble Linear drain over the Thermal break as well and working off of the edge of the Noble Linear Drain as our lowest point.

    [​IMG]

    My email from NuHeat also made their recommendations for backer boards. They include the following four options

    Wedi Board

    Durock

    Hardy Backer

    WonderBoard


    No drywall in the list.

    No Denshield in the list.

    No Kerdi Board in the list.

    No Hydro Ban board in the list.

    All cement boards..... I like that. The way it should be.

    I have no prior experience with Wedi Board and off the three cement boards like Wonderboard the best. If I had to choose between Hardy and Durock - well I would choose neither since I think both of these boards are crap.
    Last edited: May 1, 2014
  3. johnfrwhipple

    johnfrwhipple Bathroom Design & Build - North Vancouver, B.C.

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    I think you wanted this question posted here Vegas.
  4. Vegas_sparky

    Vegas_sparky Digital Billy

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    This thread didnt even exist when I posted. Quit trying to read my mind. That's bullshit! LOL
  5. DougB

    DougB Member

    I'm in Minnesota. For my downstairs bath I used a Warmly Yours heating mat and cork.

    First modified thinset and cork. Then spot glued the heating mat. Skimmed with modified thinset. Next day used unmodified thin set and Ditra.

    It's been 4 years with no problems.
  6. RedShoecounterbalance

    RedShoecounterbalance Stay away from ladders

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    I would at least consider WEDI board and a heating mat over it. IMO Wedi board is the only SOLID foam product out there, although I have not gone to a workshop for laticretes new hydroban board.

    If you hold a 1/2 inch piece of WEDI board in your hand with its competitors you may jump in my boat, then go ahead and jump on wedi board vs. others see how stable you feel.....a bonus John is it comes in 1/4 as well which would be stable over that slab embedded in MODIFIED thinset, NO ????

    Most likely would be my approach. And YEP Im gonna go ahead and mix the systems and chuck the warrantys out the window and go ahead and stand behind my work.??????? sound like a plan

    If you are concerned about sandwiching the mud pan with TS......could one not create breathable holes in the wedi material??? Break rules JOHN is all im saying.
    Last edited: May 1, 2014
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    Wedi is the only backer board that I know of that is currently approved for bonding directly to a slab. You have lots of choices of thickness, so you can set your level of insulating value you desire. EasyMat does have at least one version that is a peel and stick, but you may want a thicker version, and I think those are only available with the separate adhesive you have to spread. Wedi is likely to have a higher R-value per inch than EasyMat.
  8. RedShoecounterbalance

    RedShoecounterbalance Stay away from ladders

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    Credit where credits due.......What JIm said!!!!!! with the exception of a peel and stick. I cant sleep well with that, id have to look at the msds sheet and the chemical makeup of said "sticky stuff " id consider my warranty is shot by mixing systems and go with a thinset embedded mat system... but, JIM has some good points there.

    Again Im not a foam guy, but the Wedi material's cementious embedded fibertape Is very structurally solid when ive compared it to All others or would never had ventured into the foam market.

    1/2' wedi board is 3x5 and $30 a sheet in my neck of the woods. So its not cheap.....
  9. eurob

    eurob master tile and stone installer

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    Location:
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    Hey John , is the cork affected by flooding ?

    I will quote you some infos from Flextherm , cork over the heating cable is not recommended , not the other way around.


    '' Radiant floor heating
    --Who can install a heating cable system? --
    --What circuit voltage is compatible with FLEXTHERM floor heating systems? --
    --What are the benefits of radiant floor heating? --
    -- Can radiant floor heating be used as the primary heat source for a room? --

    Radiant floor heating can be used as the primary heat source for a room. Several factors must be considered: the level of subfloor insulation, the size of the room, the exposure of exterior walls, the window coverage, the desired comfort level and the system’s output.


    --How much does it cost to heat floors with a heating cable? --
    --Do I have to insulate the floor before installing the heating cable? --

    If you install the system on smooth concrete, the concrete slab must be insulated to prevent heat loss and maximize the benefits of radiant floor heating. There are a variety of products available on the market that you can use to create heat barriers. Insulation product suppliers will be pleased to give you some advice.


    --What floor coverings are compatible with a heating cable? --

    Depending on the product, FLEXTHERM cables are compatible with a wide range of floor coverings, including ceramic, natural stone, engineered wood, vinyl, floating floor, linoleum, parquet and carpet. For coverings other than ceramic or natural stone, it is important to always check with the manufacturer in order to make sure that its product is compatible with floor heating systems. Just follow FLEXTHERM’s recommendations to achieve the best result for your installation. FLEXTHERM does not recommend installing heating cables under hard wood or cork.


    --Which surfaces are suitable for installing a heating cable? --
    --What is radiant floor heating? --

    Radiant floor heating means heating masses directly rather than ambient air. The comfort achieved using this method is vastly superior to classical heating methods such as baseboards, wall-hung radiators or hot air systems. With their feet nice and warm, people who choose radiant floor heating are more comfortable and save a lot of energy.
    ''

    End quote .


    I've heard that Cerazorb is not so efficient as it is marketed .


    If thickness is not an issue you can explore the high density foam or the double bubble insulation in combination with a reinforced mud bed .
    Last edited: May 1, 2014
  10. johnfrwhipple

    johnfrwhipple Bathroom Design & Build - North Vancouver, B.C.

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    I have cork installed in my mudroom directly over an old cement floor right now. Walk on it daily and have yet to tile the room. Been a couple years at least. No sign of mold or de-bonding. The peel-n-stick product from Mapei looks good to me.

    With the repairs to the slab. Evidence on efflorescence on the concrete floor and the fact that a cement waterproofing material will be coated over the slab I do not like the concept of bonding to this slab and relying on that bond long term. So I could really even use the peel-n-stick unstuck for this job but I think it's best to bond it down. Easier to work with it.

    Once the heat goes on there of course is a chance more moisture will be drawn to the surface of the floor. If there is any chance that cork can mold then I think the Easy Mat is the best choice.

    Only time and testing will tell.
  11. johnfrwhipple

    johnfrwhipple Bathroom Design & Build - North Vancouver, B.C.

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    Roberto I did not know FlexTherm was also consider a primary heat source for the room. So is NuHEat. Not sure about the other players but choosing a heat source like this that is not approved as a primary heat source is a little silly when so many good sources are out there. Makes you wonder about the longevity of the heating wire if it can not handle the job of heating the room by itself.

    Often when using a cable heat source you need to heat the shower to achieve the proper BTU requirements.
  12. johnfrwhipple

    johnfrwhipple Bathroom Design & Build - North Vancouver, B.C.

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    Doug does Warmly Yours recommend Cork? What type of cork did you use? What type of modified thin-set did you use? I used Laticrete 254 to install mine.
  13. cicerored

    cicerored New Member

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    I used the easy mat in my basement with the radiant wire on top of it. It worked great. It has a rated r-value of about .5. I would go with that. Seems to be some kind on foam. So, Cement Floor, EasyMat (buy in large rolls), heating wire, Tile.
  14. johnfrwhipple

    johnfrwhipple Bathroom Design & Build - North Vancouver, B.C.

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    Did you get the primer included with your roll like mine?

    Thanks. I'm going to design it like this.

    Cement Floor
    Primer
    Easy Mat
    NuHeat Wire
    Mortar Bed (Laticrete 3701)
    NobleSeal TS
    Tile
    Grout

    Pretty safe specification detail. Might have to shim the drain up a little to meet the 2" requirement of Laticrete. If the customer does not want to buck up for a premium mortar bed then I guess a simple 4-1 mix is in order.

    My client emailed me this info last night. He pulled it I think from this link below;

    http://www.warmyourfloor.com/cork-insulation-for-concrete-slab-sold-by-sf.html

    His message to me via email.

    "I have found the small print “ Not recommended for shower floors or outdoor use

    I am not sure the reason behind this thinking, perhaps it is because most people do not use Noble TS over the mortar ."
    Last edited: May 2, 2014
  15. DougB

    DougB Member

    They were 2' x 3' sheets - 1/4" thick. I used an Ardex ( can't remember the number ) modified thin set. It was a very cold winter here in MN. The floor was nice and warm.

    I wouldn't use heating cable as a primary heat source. However, we have an unheated foyer ( 6' x 8' ) also with a Warmly Yours heating mat - and it made a real difference.

    I'm in the middle of remodeling my master bath. That Ardex X-77 is really nice thinset!
    Last edited: May 2, 2014
  16. johnfrwhipple

    johnfrwhipple Bathroom Design & Build - North Vancouver, B.C.

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    X77 is like butter. I love it. X5 is also nice for installing sheet membranes. It has a very fine texture that is accepted by the sheet membranes well. Never tried setting cork with X77 but imagine it would do the job. You can use it on your swimming pool!
  17. eurob

    eurob master tile and stone installer

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    I have no problem in using the Flextherm as a primary heat source and in shower installations . Besides , you can always install a hidden wire in a designated area to later install a back up -- surface -- heat element .
  18. eurob

    eurob master tile and stone installer

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    Location:
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    I thought the X77 is some kind of pookey , but no butter that I know ?! LOL
  19. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    Whether electric floor warming can provide all the heat required for a room is entirely dependent on the heat load analysis that should be performed before doing any heating/cooling. There is a practical limit of how dense you can place the heating wires, and this is what limits the amount of heat. Many of them peak out at around 10-12W/sqft, so you need to see what the one of interest could provide then, compare that to the heat load analysis to see if it is enough. Now, depending on where you live, the house, the orientation, the amount of insulation, air infiltration (all things that should be considered when planning any heat work), none of the electric floor warming companies will guarantee they can be the primary heat...all they'll guarantee is that they can make the floor feel warm, and, that may be all that you need. One watt/hour=3.412142BTU, so somewhere around 35BTU/sqft is the max from most systems (again, check their specs).
  20. johnfrwhipple

    johnfrwhipple Bathroom Design & Build - North Vancouver, B.C.

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    I think all the crap above me in lay man terms means Schluter's heat cable is not allowed as a primary heat Source. Nu Heat's cable is my preferred heating cable. It is allowed to be used inside a shower. It is also allowed to be used as a primary heat source.

    JW

    www.No-Curb.com - my blog site on Barrier Free, No Curb, No Dam and Hobless Showers​

    (604) 506-6792 jfrwhipple@gmail.com
    Last edited: Oct 30, 2014
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