# R & R subfloor for even result?



## John Pride (Oct 31, 2007)

I am a residential contractor who is going through a few changes due to health issues. Along those lines, I am working less and bidding more. 

I have done a bit of tile, and it all turned out well. I want to do a lot more, and I am bidding a job that involves replacing carpet with hardwood in one room, and also replacing vinyl with ceramic in an adjoining area which meets existing carpeting at another location (not to be replaced with anything other than carpeting) as well. All areas are on the same plane now.

I assume (built 2000 or so) I've got typical subfloor and underlayment, plus the luan under vinyl areas. I intend to remove the baseboards, vinyl and luan in the vinyl areas, which is about 400 sf (foyer, hall, kitchen/eat-in, bath, laundry). Can I just leave the subfloor in place, tightening it up really well, and run tile over that substrate? Hmmm. Or, do I need to glue and screw 1/4" cement board (or 1/2"?) over it? Or, if I need backerboard, do I need to cut the subfloor out and replace it with cement board, giving it a laevl plane with the wood area and existing (to remain) carpeting?

And, as long as I'm asking, and since the permit office was not crystal clear when I called, do I typically need a permit if I replace just underlayment, or only if I go down to the subfloor?


----------



## R&D Tile (Apr 5, 2005)

Permit?, no tile police here.:whistling

What do have for a subfloor under the luan and vinyl, how many layers of what and how thick, you WILL need a CBU or membrane, all depends on your answer.


----------



## Home Serve (Apr 26, 2007)

Sir: I'd do some serious research on tile installation if I were you before bidding or installing it. This Contractor talk site may have some info on it and here is another 
http://forums.jlconline.com/forums/forumdisplay.php?f=13
You've got to know exactly what your support is for the tile before anything!!
Dave


----------



## PrecisionFloors (Jan 24, 2006)

We also need to know what the joist spacing and span is. You must meet L/360 deflection requirement for ceramic and L/720 for stone. Once those have been met you need 1 1/8" of plywood subfloor. I usually put down a layer of 1/2" BC over the existing 3/4. Remember backer board does NOT count toward the 1 1/8" spec. CBU does nothing for strength in the assembly.


----------



## John Pride (Oct 31, 2007)

I need to verify this, but it's a house age and location I tear into a lot, so let's base your answers on 3/4" T&G subfloor and 1/2" underlayment. The U/L should be ext. ply since the areas are all wet locations (Kit, bath, laundry). Luan and vinyl should be over that.

Joists are on 16's and span is 14' max. Not sure of joist sizing, but will look at all above to verify and adjust to any inaccuracies.

Membrane? Hmmm. What I need to know is what will leave a proper substrate and still avoid inconsistent elevations regarding adjoining areas.

And DAVE! I appreciate the link to JLC and the caution, but I thought I WAS "looking well into my going" by posting this question?! I am a contractor, but not knee-deep into tile work, that's all! Used to run big stuff for industrial GC's, so maybe I'm too used to not being expected to know all trades without asking for clarification before proceeding. 

A PERMIT note: I do think I need a permit if I pull the underlayment, definately if I pull the subfloor, but I'll call Permits on that later. It's so routine these days, and usually required. I haven't worked without a required permit in years. Too many sad tales of work done that way holding up home closings. One guy on Long Island, an outlaw of mine, bought a place, lived in it for 15 years, sold it and had to demo and replace a deck (there when he moved in, mind you!) in order to close escrow and move to Hilton Head. Deck on stilts, pier to dock, ouch! 

But I did NOT know that cement board doesn't add to 1-1/4" requirement! 

And Precision. I am from your area, grew up in Hilton, last lived in Poquoson. Have a brother still there.

Thanks, guys. Any input will help.

John


----------

