Radiant floor heat.

[todmcgee]

First thanks to all. This forum helped my small bathroom tile job turn out very nice.
I am looking at 2nd floor master bathroom now. It will be OSB, floor heat, ditra, travertine. This will be next to 3/4 hardwood floor. 1st question: is there some type of insulation board? I can only find stuff in the UK. Or do I even need it? 2nd question: will this be to high for a smooth transition?

[WendyHMN]

While the pros are recovering from Friday night parties, why don't you tell us more about your current floor. What kind of joist support do you have (you can play with the deflecto in the blue bar at the top of the page), how thick is your subfloor and how many layers? Natural stone is very picky about its substrate. It likes a very stable structure and several layers of plywood.

[pktaske]

From the title of your post, is your concern that the floor heating element+insulation will overly elevate your floor? It is my understanding that insulation is only recommended when installing over concrete/slab (like my BR) as it tends to suck heat. But there is even debate whether that's at all necessary. But is doesn't sound like you need it over wood.

I decided to put down this. I got it @ $18 for 8 square feet, free shipping.

http://www.cerazorb.com/

[todmcgee]

I just want to make sure I am heating the floor and not the space between floors. I was told all the heat will go to the cold space between the floors and not up through the tile. (Not heating with this, just keeping the feet warm) The more I read the less I am trusting this individual. As far as structure. I know I have engineered joist. I tried to get the house plans but the builder seems to be out of business. By the joints in subfloor I would say they are 19.2 on center. As a last resort I can open the floor up and see what I can see. Any guidance would be appreciated.

[TechHead]

I'm not a pro but, from engineer Bob's pdf on thermal loss over a slab, 1/8" of cork made heat loss neutral. Usually in non slab situations people dont worry about it.

Stone (travertine) has the highest requirement for minimal deflection. 19" on center doesn't sound like a promising start. Engineered joist is a plus usually, small area is a plus, direction of joists in this small area my be another plus.

Travertine is a pretty soft and porous stone, using it in an area that will often get wet and be cleaned often with a variety of cleaning agents may be asking for more trouble.

Are you sure you cant be just as satisfied with a porcelain travertine look alike that would greatly relax the deflection requirements and prove to be much more durable?

[mctile]

You are asking for trouble with a stone installation on single layer OSB.

[todmcgee]

Thanks all
Looking for porcelain. Not going to worry about the underfloor heat. Sounds like it will be fine for what I want. Interestingly I have found no nails or screws in the subfloor except a couple at joints. When I put wood floors down in the bedrooms there were at least a few nails. Could explain the creaking floor.