Wood flooring on a slab?

[RainDog]

Could be thread drift here, but... I have a heated slab. Wifey wanted wood over it. I researched, considered ceramic or porcelin  but  ended up DIY acid staining the concrete. No wood buckling, no grout lines. She's happy, I'm happy.  www.kemiko.com  There's others, this is the brand my local supplier had.

Have any idea what that radiant heating cost per square foot, roughly? Oh, and the acid stain too. Just a ballpark guesstimation?

[davidj]

There's a recent article in Fine Homebuilding talking about hardwood over concrete slab.  They used a high-quality vapor barrier (10mil or 15mil of custom reinforced poly vapor barrier) over the concrete followed by two layers of plywood, I think something like 5/8" each.  I can't quite remember, but I think the sheets of ply were perpendicular to each other too.  I.e. you basically build a new subfloor floating over the concrete and use a lot of plastic to keep the moisture out.  Certainly not at the cheap-and-quick end of the possible options.

[waggin]

Also saw the Fine Homebuilding article.  Thought it had a foam board seam sealed w/house tape, then plywood, then hardwood.  Lots of height stack-up, so plan on major stair adjustment or goofy (and dangerous) short step at bottom.

[builderboy]

Raindog, IIRC it cost about $2/sqft to have 2"foam and the hot water tubing installed (over & above the original slab quote). The acid staining cost me about $1/sqft BUT I did the labor which is extensive in the prep phase if you don't have a new clean slab. That bought the acid stain & sealer, rented a floor scrubber for 2 days plus various incedentials needed for the task. Prices in Canadian bucks.

[RainDog]

Raindog, IIRC it cost about $2/sqft to have 2"foam and the hot water tubing installed (over & above the original slab quote). The acid staining cost me about $1/sqft BUT I did the labor which is extensive in the prep phase if you don't have a new clean slab. That bought the acid stain & sealer, rented a floor scrubber for 2 days plus various incedentials needed for the task. Prices in Canadian bucks.

Thanks a lot. Sounds like you got a great price on that radiant flooring. I'd like to do the same, but am still wavering. The prices I've seen seem to be in the six bucks per sq ft range.

Would you do that concrete floor if you had to do it all over again? I love the looks of those, and have lived in loft-type apartments with concrete flooring, but I sure do hear a lot of folks recommend against 'em, so I do have to wonder if maybe I just missed something, somehow.

[JRR]

The article, "A Wood Floor That Can Survive Anywhere." , as mentiioned above, appeared in the Nov 2009 issue of Fine Homebuilding. 

There is an interesting response: "A Warmer Basement Floor" in the "Letters" section of the March 2010 issue of Fine Homebuilding.

[Okie_Bob]

Hey guys I wanted to jump in here. I used ceramic tile on top of Hardi backer board screwed down on
1 1/4" T&G plywood on top of wood I-beam joists in a pier and beam foundation. Tile has been in now
for two years and not a crack anywhere. Have I just been lucky? Do you think I will get cracks? And if I do,
how do I make it right? Oh and I built a shower on the same floor using ceramic tile too. And no cracks there either.
Okie Bob

[MountainDon]

Your floor should be fine as long as the deflection on those I beam joists is within the allowable ceramic tile range.

L/360 is the maximum deflection for ceramic tile, L/720 for natural stone.


If you ever do get cracks better talk to your builder about his warranty.   

[Redoverfarm]

As Don has stated.  You are probably within your tolerable deflection.  If Not and it would ever fail you could sister some addition joist to your existing or put another beam midways of your span.