Replies

1. 
   JTC1 | Feb 26, 2007 08:41pm | #1

   Can't comment on the variable of radiant heat.

   Assuming joists of appropriate size for their span set on 16" centers, I think you will be very happy in the long run by using 3/4" (23/32") T&G plywood and then the 3/4" oak.

   I think the plywood is better than OSB for holding the flooring nails.

   Be aware that all 3/4" plywood is not created equal - look at the APA grade stamp - you should see the term "Sturd-I-Floor" for flooring use (or the term "Uni-Flor" from PTL inspected material - same specs).

   I like to glue (subfloor adhesive, don't skimp) the ply and nail with 8d annular ring nails, some will undoubtedly chime in and vote for screwing the plywood - I never had any problems / complaints with ann ring nails - just use plenty of them. I can bump fire nails much quicker and spend less $ than driving screws.

   Good luck!

   Jim

   Never underestimate the value of a sharp pencil or good light.

    

2. 
   Geoffrey | Feb 27, 2007 01:34am | #2

   All,  

      Have you considered installing the radiant over the subfloor?, then installing the hardwood over that?  It's easy enough to see the tubing to avoid nailing into it and saves the time of you clipping all the nails off on the basement side, and you get better effficiency from "on top" installations.

   either way, don't use the OSB, it's not as good for nail retention IMHO, use the graded ply, or Advantech.

    just noticed you mention 2 layers as an option, given that question, I assume that the extra thickness from installing radiant (typically 1/2" thick) above the subfloor would not be an issue, and it would add even more structure to the floor.

                                                                                                                Geoff

                                                   

1. 
   FastEddie | Feb 27, 2007 01:55am | #3

   To the OP:  Advantech osb would be a good choice, regular osb would not.

   Geoffrey ... Are you proposing to nail the oak strips directly over the electric mat?  Even if you miss the wires, I can't imagine that the wires would hold up to the abrasion.  And I really doubt the warranty would hold."Put your creed in your deed."   Emerson

   "When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it."  T. Roosevelt

1. 
   TomW | Feb 27, 2007 02:12am | #4

   I hope he is not using an electric mat under that much wood. Sonds very expensive o operate.

2. 
   Geoffrey | Feb 27, 2007 02:26am | #5

   Ed,

        When you said radiant heat, in conjunction w/a wood floor I assumed you were using a FHW system not electric. I don't think electric is an appropriate choice for under the floor (basement side of subfloor) heat, at least I would guess it to be very inefficient from a heating standpoint.

   Radiant I was refering to uses pex tubing installed in a dado cut in the 1/2" ply, which is in strips 8"x48"(or similiar).

   sorry for the confusion

                                         Geoff

1. 
   FastEddie | Feb 27, 2007 06:26am | #9

   Duh.  My bad."Put your creed in your deed."   Emerson

   "When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it."  T. Roosevelt

2. 
   AllTrade | Feb 27, 2007 03:30am | #6

   Thanks all. I am using pex tubing and plates under the floor to spread heat. I could go on top and flood with thinset but that is  o lot of thin set eh?  I guess staple pex to floor and flood with thinset then install hardwood directly on top while avoiding pex? Do they nail through the thin set or would I use sleepers? I have a thread in energy section with a lot more details under the message "something for me"! Would love to hear what you guys think after looking at it.

   Edited 2/26/2007 7:36 pm ET by AllTrade

   Edited 2/26/2007 7:39 pm ET by AllTrade

1. 
   Matt | Feb 27, 2007 03:49am | #7

   I don't know much about hot water radient heat - they don't use it hardly at all in theis climate...

   But, regarding your statement about thinset... you don't really mean thinset do you?  Wouldn't it be gypcrete (lightweight concrete)?

1. 
   AllTrade | Feb 27, 2007 03:58am | #8

   Yes sir,

    

2. 
   FastEddie | Feb 27, 2007 06:27am | #10

   No, you can't nail through thinset.  Well, actually you can, but it will shatter."Put your creed in your deed."   Emerson

   "When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it."  T. Roosevelt