Replies

1. 
   Jess_Messick | Mar 07, 2001 02:08am | #1

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   Check out Junckers hardwood floors-they make the only true hardwood floor that can be laid over hardwood floors-FH approves...J

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   David_Embro | Mar 07, 2001 08:31am | #2

   *Thanks.. I have checked them out before. There price is a little steep.. I guess it doesn't help that i'm up in Ontario Canada. I have also seen a method where they lay in 2x2's as nailing strips before you pour the concrete. Does this method work? It looks like it may have potential. Anyone have any ideas that may help? Thanks again!David

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   david_thodal | Mar 07, 2001 09:20pm | #3

   *David, One option you may be able to use is to run two courses of cdx crosshatched so your joints are all offset. Glue and screw these sheets together but otherwise let them float ontop of yor slab.Then you lay your paper and install your floor as you would on stick frame subfloor. Use 1-1/2 flooring nails to avoid over penetration into the slab.Considerations on this install are your elevations however. Will you have clearance for doors? Window heigths? etc. I usually figure 2-1/4" elevation off my slab to finish floor heigth.walk gooddavid

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   Buck_Olmsted | Mar 12, 2001 10:54pm | #4

   *I didn't see your question until today or I would have responded sooner. My advice would be to never put a hardwood floor over any kind of in-floor heating system. If you check with the hardwood floor installers, most of them won't guarantee their work when installed in this manner. The reason being that the heat causes the wood to dry out excessively which in turn causes large gaps to form between the boards. In over 30 years in the field of architecture, I have never seen a hardwood floor hold up in this situation.

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   bushleague_ | Mar 13, 2001 03:53pm | #5

   *Buck, you mentioned never putting a hardwood floor over an in-floor heating system. What about with a joist system with the heating tubes against the bottom of the subfloor? Are there others who have experienced problems with in-floor heating?Jeff

2. 
   Mongo_ | Mar 16, 2001 08:58am | #6

   *Buck, Come on over my house...it takes a carefully designed system, but it can be done. Would I trust your average flooring sub or your uncaring RFH design team that works using "rules-of-thumb?" Heck no.Dave and Jeff...I agree with most of the theory and practical info in this article.All that said (and read), if you can't ensure a well-designed system, your best fallback will be to use and engineered (ply) strip flooring with a show layer made of real wood. The ply makes it less susceptible to the movement that Buck has seen. The thinner layer of show wood does limit you when refinishing...usually the floors will be screened instead of doing a wholesale sanding. Some good, some bad...

3. 
   bushleague_ | Mar 16, 2001 07:10pm | #7

   *Another concern is the feel of the floor. I'm not sure how a concrete floor would feel on the joints. How does a wood floor (with plywood subfloor) feel when laid directly on concrete? Is there any "give"?Crazy as it sounds here is what I'm thinking of doing: Pouring a insulated monolithic slab foundation and living on it for the first year or so or until I save enough to purchase hardwood floor. Then, laying sleepers on top of it with isulation between them (and maybe underneath (foam) if possible)and vapor barrior above insulation. On top of that, reflective material, then tubing, subfloor and finally hardwood floor. Any suggestions?Jeff

4. 
   Jim_K_ | Mar 16, 2001 07:36pm | #8

   *The good thing about concrete floors and joints is that if the joints accidentally fall on the floor, they won't burn it...---This seems like a lot of work and material to solve a problem that may not even be a problem. My suggestion is to find a wood on slab installation and walk on it to see if it bothers you before you commit to all this or other effort. Tube in slab and floating floor over pad--if you're concerned about hardness--seems a lot simpler and cheaper.

5. 
   david_thodal | Mar 17, 2001 06:10am | #9

   *Mongo, Thanks for the article. It was interesting. If you have read any of my other postings on flooring, you will see I have been almost preaching about DRY, both in flooring and subfloor.One consideration often over looked is that though wood has a higher R-value than say concrete or tile, it has some value as a thermal mass. Warm it up and it will hold heat longerr than said concrete or tile.I agree cooler temps are needed in your heat tubes. I find 90degrees works well. I stick with that and tell my clients it will take longer to warm the floor. That is one reason I reccommend a secondary heat source, ie wood or gas stove for those quick warm ups.Back to floors, though. I like solid wood floors. I like the feel of them, the ability to refinish them and I hate glues, so that is what I install.Keep them dry and walk gooddavid

6. 
   david_thodal | Mar 17, 2001 07:30am | #10

   *A follow up to the last post. Why I like running double sheets of cdx over the slab as a subfloor to wood flloring.Double sheeting plywood over a radiant slab is an effective vapour barrier. Though not 100%, if you lay your plywood down dry and your flooring dry you will have far less problems with moisture migrating from the slab into the flooring.The plywood besides acting as a thermal mass also disperses the heat from the radiant so you have a more uniform heat, less hot spots that may cause problems with the finish floor, especially if the heat is run at a higher temperature. I believe you have fewer problems with a properly nailed wood floor than glued down. Using flooring nails and rosin paper you allow the flloring to move freely with seasonal moisture and heating/cooling cycles. This helps reduce buckles and potential for cracking. As far as shrinking, nothing will help with that except installing the floor at an optimum dryness over a subfloor that is dry.walk gooddavid

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   David_Embro | Mar 17, 2001 07:31am | #11

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   I have a little dilemma... What is the best method of laying a strip hardwood floor over radiant floor heating? The radiant floor heating will be hydronic installed in 1 1/2" concrete. The issues are... Can it still be nailed down? What about a floating floor installation? Help!! What have you seen to be the best method of achieving great results...?
   Thanks in advance for all your ideas..
   David