Joist Heating w/OSB Subfloor

Riles

Anyone ever had any problems with a joist heating job where OSB was the subfloor?

Just installed one, not hooked up yet. All my joist heating jobs prior to this have been CDX plywood.

No plates used, actually after the K-State research. I'm doing a little experiment of my own. Install is as follows:
Existing slab on grade, adding two rooms to back of garage. Shot 2x4 pressure treated sleepers down flat, then standard 2x4 on top. So, 3" total gap from slab to subfloor. Then I put down 1-1/2" Poly (R7.5) in between sleepers. Leaves 1-1/2" space. Secured joist hangers and tied tubing to top, so tubing sits slightly below floor. Then OSB subfloor.

One Loop, 200 feet, 1/2 Wirsbo Hepex. Two small rooms, one will be ceramic tile, & one floating wood floor. Just using as floor conditioning.

Been involved in numerous joist heating jobs with and without plates with no problems as long as we followed the design. I always use the Wirsbo design program.

kevin

osb

Is it osb or is it Advantec brand osb? The Advantec is really great stuff,very stable, very durable, very water resistant. Either way i have not had a problem or seen a problem w/ it. Best of luck , kevin c.

Duncan_2

Jeff,

Mind if I ask what's the experiment?

Riles

I have never

had this type of install. When I went to build these two rooms I wanted to get the finished floor off the slab. So, I figured on trying this. Then, with all the question centered around the K-State findings mentioned in the article in P & M Engineer I figured I'd see for myself how this particular install would work. I had some extra tubing and decided to install as described.

I have another, non typical (for me), in my master bedroom. I put down Wirsbo Quik Trak for floor conditioning (Home heating if Heat Pump). Instead of pulling up all subfloor to insulate below, I stapled down Low-E. Then screwed down the Quik Trak and put a floating floor (Pergo style) down. I'll tell you one thing standing on the finished floor is much firmer than I expected. This will be started up late this fall at the same time as the garage project.

Hey anyone ever used a small E-Max 3 KW instanteous heater?

I am a wholesaler that ends up on many jobs working with contractors. So occasionally when the opportunity arises, I try something different to see if it will be a solution for that application.

In both cases, I figure I'll take a lot of floor temps with my laser thermometer to see how the systems are working.

Earthfire

Osb subfloors

The only real concern is thatmost tile manufacturers and thinset suppliers want 1" plywood under the title and specifically frown at osb. If you use a good CEMENT backer board under the tile ( ex. DUROCK) you shouldn't have any problem . In fact the radiant should help keep the OSB dry and prevent swelling.

hr

The temperatures are a concern

with any wood product that hast heat below it. Personally I would hate to see any ply or OSB run above 140. I think this is the number most engineered wood manufactures are comfortable with on a CONTINOUS basis. Yes I know the roof comparison with temperatures above 140 under the shingles, but this is not a 24/7 condition like a radiant floor may see in design conditions.

Check out the Watts Radiant 862 over floor system for what you describe, it may save a lot of labor.

For limited BTU/ sq. ft. suspended tube has a place. Deciding what that BTU/ sq. ft. number is will be the challange! Once again, personally I think 15 BTU/ sq. ft is easily done with low (below 140) supply temperatures in suspendedapplications.

hot rod

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