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Gordy's copper floor warming work of Art!

copperkidcopperkid Member Posts: 22
Hey Gordy now that my addition is wrapping up I plan on routering my floor similiar to yours.  Did you put wonderboard or durock over the tubing and if so was there any kind of barrier between the copper and cement board.  I always use thinset when I use the board.  Would I need to go to 6"centers if this will be used for heating ?  I was thinking of putting the pex in but the copper has no future use as of right now, I would use soft copper for the returns and Silfoss all the joints.  No worry about any leaks with that stuff.  I plan on starting it this weekend and need some pointers. Thanks


  • GordyGordy Member Posts: 7,122
    edited January 2014
    I used

    Hardibacker 1/4" back buttered with thin set. I filled all the tube grooves with thin set also. I went 8" on center since I have radiant ceilings in the kitchen also I was not trying to heat the space tile warming. All though it would heat the space with just the floor. Depends on your heat loss for the room. 6" will lower supply temps a wee more.

    I found it easier, and neater to back butter the panels before laying in place, and screwing.

    I did do an area with heavy gauge aluminum foil tucked under the tubing in the groove, and covering the entire area between the tube a plate. No notable difference from where I did not do it. So waste of time there.
  • knotgrumpyknotgrumpy Member Posts: 207
    This thread

    Is worthless without pics...
  • GordyGordy Member Posts: 7,122
    edited January 2014
    I would have to

    Get into the old desk top dig some out. Revert to the warm board heat ply thread for one.
  • knotgrumpyknotgrumpy Member Posts: 207
    Got it

    Thanks Gordy.
  • copperkidcopperkid Member Posts: 22
    Doesn't the thinset attack the copper

    Does concrete or any kind of mortar or cement product attack copper.  I was always told as an apprentice it would take 50 yrs to eat thru that copper.  I have pulled out copper that was either mortared in the block, or cemented in place.  The copper was fine after 40 yrs plus.Whats the correct method, as most Steamfitters just do things because the journeyman before him was taught that way.  I don't know?
  • GordyGordy Member Posts: 7,122
    edited January 2014
    I have

    Copper in concrete, copper in plaster, copper in mortar bed, and now copper in thin set (unmodified no polymers).

    None showing issues as of over 60 years except my thin set install

    High flyash content concrete will ruin copper

    High ph soil

    High ph water.

    Sloppy fluxing.
  • copperkidcopperkid Member Posts: 22
    You said the thinset was unmodified.

    Why did you use unmodified thinset and did you have any issues with the install. You mentioned "except the thinset install" concerning any issues?  Please elaborate. I have roughly 300 ft of 1/2" od L copper tube I need another 250, I priced out the pex for the total job and it is pretty close to the copper.  Now I got to find a 2 hp router.
  • GordyGordy Member Posts: 7,122
    No issues

    You are suppose to use Unmodified for the cement board bed. I used modified for the tile.

    What I meant was all my copper is imbedded in some kind of cement product. It's all stood the test of time with no issues over 60years except the thin set which I don't expect issues with that either. It's been about 10 years since I did that
  • copperkidcopperkid Member Posts: 22
    Ok I just use what my friend uses

    he's a professional tile layer, and he uses the same stuff regardless.  I saw you used copper plated strap to secure the tube, I've seen that style hanger rust and corrode copper tube.  I wonder is this from a combination of a sloppy plumber and his over use of flux.  Why are plumbers and fitters soooo lazy and leave there joints green?  That is my biggest pet peeve.    I just don't want any issues down the road any other ideas for securing it,the talon clamps are too tall. 
  • GordyGordy Member Posts: 7,122
    edited January 2014
    Galvanic corrosion

    Needs some things to be in place to happen. It's not just two dissimilar metals.

    The pic shows my ceiling radiant during a kitchen remodel in which I removed some existing soffit. Note the hangers for the tubing, and the mesh for the inside corners of the plaster. Lots of dissimalar metals there, and 62 years old.
  • GordyGordy Member Posts: 7,122
    Un modified

    Is what I used. Did not know if the polymers would have an effect on the copper. May or may not. You can use either unmodified, or modified. Unmodified is cheaper. Your only trying to eliminate voids under the backer board.
  • kcoppkcopp Member Posts: 2,774
    Whats in the...

    basement to drive the system? Gas, oil, ? How do you mix it down and what was there originally for equip?
  • GordyGordy Member Posts: 7,122
    edited January 2014

    WM cgm-7 NG

    Compression x tank.

    Bypass piped with taco panel troll mixing valve original.

    This boiler replaced the original that lasted 41 years.
  • RobGRobG Member Posts: 1,850

    Gordy, what type of backer is that copper in the soffit attached to? If that is for ceiling radiant is there insulation above it. I'm just wondering because it looks like particle board or maybe lauan.

  • GordyGordy Member Posts: 7,122

    Plaster board. It does look like partical board not as hard.
  • copperkidcopperkid Member Posts: 22
    I finally ffinished the sleeper work

    after my Dad and I ripped up the top 5/8 subfloor ripped it into strips and routered the glued and screwed down area,  My 3/8 L is in and holding pressure, I hit it with nitrogen since I had a bottle laying around hasn't dropped at all.  I am almost finished with the wonderboard.  For anyone doing this, Gordy is right you need a 2hp or better router.  I got the Ryobi from H D and figured its a throw away, actually did a decent job as long as you watch for those hidden nails.  I'll post pics of the floor soon.  23 sheets of wonderboard is enough for my knees. 
  • GordyGordy Member Posts: 7,122
    23 sheets

    Wait till the till!

    Did you mud the tubes?
  • copperkidcopperkid Member Posts: 22
    Yeah they were all mudded in

    ,now if I can ever get it hooked up.  Trying to get the time to set it up, right now the boiler is only heating domestic.  Glad I added a larger furnace, those -17 degree days last week were cold.  I made my own manifolds that have been sitting for 2 months already.  Soon It will run, maybe not this winter but definitely for next heating season.
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