I think I am halfway towards making a bad tile floor and trying to figure out which way to go to save myself.
My house is from 1895 and had wood plank yellow pine floor. In the kitchen there were 9" tiles underneath subfloor undereath linoleum. This was half pulled up when I bought the house (my house was abandoned, go figure.) Anyways I pulled up BOTH layers of floor down to the original planks. Then I went out like a sucker and bought 1/4" hardiebacker and started screwing it down. Once it was down I tried to level out a section of the floor with floor leveler ON TOP of the hardie backer.
I got pulled away to do a bunch of other work and was getting back to the kitchen to install my 17" porclein tile when I had that sinking feeling that something was wrong. I did more research that contradicted my original research and now I am in a bind. I didn't put the thinset below my hardibacker or a subfloor over the planks. But I have a large section of floor with leveler that is covering the screws that I wish i could undo and start over....
I also have to put this underneath a giant radiator. Is there anything I can do, maybe an additional layer of 1/4 inch hardie? Any options at all?(other than total destruction) Thanks.
You need to remove everything down to the subfloor and start over.
First of all you need to determine if the framing in stiff enough for tiles. Being an old house it's likely it did not necessarily meet codes, but it's possible it's very well built. So, inspect and measure; the joists, see if you can determine the species, the joists on center spacing, and the unsupported span of each. Then tell us about the subfloor, you say they're planks. What thickness and width. What's the condition and is the floor flat? Use an 8-10 ft. straight edge or laser device. For 17" tiles I'd want it flat within 1/8" in 10 ft. of plane.
Once that is determined OK, you will install a layer of underlayment grade plywood, (prob 1/2" or thicker), then your Hardie into a bed of thin set and screwed and taped etc. Then the fun part...the tiles.
The radiator gets removed then re-installed of course.
TILE GUY - retired- TROY, MI - Method & Product suitability consulting.