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radiant floor heating

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http://boards.diynetwork.com/eve/forums/a/tpc/f/8491013504/m/7613984277

Jul 24, 2013, 06:23 AM
paul mellone
radiant floor heating
I started a project laying out 750 sq ft of 12x24 inch ceramic tile over a cemented basement floor.The floor was poured with 4 inch concrete over hydro radient tubes and was finished with a rotary finisher.I found that my tiles are not comming out even due to the concrete being bumpy.I did not use any leveling system such as cement backer board being afraid that it would compremise my heating system.Would the backer board take away from my heating system?If the answer is no then will I have to take out the tile I have cemented in which is aprox 200 sq ft ? Please help
Jul 24, 2013, 08:54 AM
Jaybee
You don't need to solve your problem by adding backer board - you need to change your thinset mix. Making a thicker thinset will give you more room to level each tile. There are thinsets designed for marble tiles (that typically have no bevel on the edge). The thicker mix (around 1/2") helps cover any irregularities and gives your room to level each tile.

The down-side is that it's a difficult install that takes time and patience to get right. I've seen many tile guys with years experience not able to lay a good floor under these conditions as it takes a very precise hand to perfectly level each tile and keep them on the same plane with all the others.

However, the in-floor radiant heat will work fine through the thicker thinset. The heat would also work under backerboard, but not as well. Basically it would take a lot longer for the floor to heat up although it would then retain it's heat for longer. But, since there is no reason to go with a backer over a good concrete floor, I'd go with a thicker thinset mix.


Jaybee
Jul 28, 2013, 03:33 PM
paul mellone
thanks jayzee for your quick response...a couple more questions should i use a 1/2"x1/2" or 1/2"x3/8"trowel ?i was only able to find a 1/2"x1/2" trowel at ace hardware
also what would be the best way to remove my 12"x24" tiles that i need to replace?[they're set in pre-mix thin-set not the kind you have to mix]i'm guessing to use a cement chisel and try to get under it to pop it out.
thanks for your expertise and help
paul