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We are installing a hydronic system in the floor of a house we are building. However, we have different finished floor conditions, requiring different approaches. One finish floor is simply a scored and stained concrete – so that is a simple installation. The other, however, seems more complicated. Part of the house gets hardwood floors. In one area, its a slab on grade condition. In another area its over floor trusses.
For the slab on grade application, the Hydronic Sub is recommended a floating floor system with the following components: Slab. 1.5″ polystyrene insulation GLUED to slab. 1.5″ of gypcrete (which contains the 3/4″ tubing 12″ oc.) 1/2″ plywood simply laid over gypcrete (floating.) Another 1/2″ plywood laid at 90 degrees to previous layer – glued and screwed to previous layer. Hardwood nailed to that. My concern is that this system will move up and down – relative to a slab area which butts this area. Also, I’m concerned about squeaking, etc.
Any experience with this system? Problems? My Builder inclination is to nail the fire out of everything. But the radiant guy tells me this system is more efficient than the sleeper approach I’m thinking about.
Replies
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William,
The floating ply sandwich is a good method. Here's a referral that may give you a warm fuzzy.
Regards,
Mongo
*I wanted alot of wood flooring in my radiant-floor heated home and spent considerable time looking at alternatives. I poured 1.5" gypcrete over the subfloors (with the tubing in the gypcrete of course) and insulated under the floor with fiberglass insulation. I then decided to use a prefinished tongue and groove wood floor product directly over the Gypcrete (Harris Tarkett Longstrip). The planks are glued on the tongue and groove seams (no nailing) and float over the gypcrete with a thin 1/8" foam pad.I decided on this for several reasons. First of all, the wood is very dry and stable. Now 2 years later there are no gaps (this flooring will expand and contract as a single unit when glued). I know several people that used regular nailed wood flooring that have large gaps in the boards - remember you are exposing this floor to wide temperature fluctuations. Secondly, there is much less mass to heat than any sleeper system - (responce times are fast). Thirdly, these prefinished floors have very good finishes (we have virtually no scratches yet - my last home had wood floors that became scratched very quickly to normal wear and tear). You can refinish this flooring twice but I bet it will be a long time before it would even be a consideration. Forthly, this was a much cheaper alternative than a sleeper system. Lastly, the floors look very nice. I even did a couple rooms with some designs (darker cherry on the perimeter and light maple in the interior).I am very happy with my decision. To tell you the truth, I actually bought my flooring over the internet (www.hoskinghardwood.com) and saved a bundle over the local stores - they shipped it to me quickly and the shipping cost was less than the local sales tax. As I recall, I paid about $5 per sq ft for the flooring.
*How do you like walking on a floating floor? How much "give" does it have as you step? I tried a section as floating, and we didn't like the effect, so we went with glue-down and are happy with the solidness. Of course, it's not heating season yet, so...
*You are right that there is a slight bit of give when you step on the floor but the pad is very thin and I really haven't paid any attention to it. It certainly not does not detract from the floor and in a radiant heat application it makes alot of sense to allow for expansion and contraction.If I was using a standard nail down wood floor over radiant heat, I would make sure the wood is as dry as possible (measured with the device they use to measure moisture content) and I would prepare myself for gapping in the winter months (it is unavoidable but not necessarily the end of the world).
*I was looking to use that same glue on edge floating technique. I didn't know if it would work without bowing in one direction or the other but, sounds like you had good luck. I was wondering how thick the wood strips were that you used and if you usedquarter sawn lumber??
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We are installing a hydronic system in the floor of a house we are building. However, we have different finished floor conditions, requiring different approaches. One finish floor is simply a scored and stained concrete - so that is a simple installation. The other, however, seems more complicated. Part of the house gets hardwood floors. In one area, its a slab on grade condition. In another area its over floor trusses.
For the slab on grade application, the Hydronic Sub is recommended a floating floor system with the following components: Slab. 1.5" polystyrene insulation GLUED to slab. 1.5" of gypcrete (which contains the 3/4" tubing 12" oc.) 1/2" plywood simply laid over gypcrete (floating.) Another 1/2" plywood laid at 90 degrees to previous layer - glued and screwed to previous layer. Hardwood nailed to that. My concern is that this system will move up and down - relative to a slab area which butts this area. Also, I'm concerned about squeaking, etc.
Any experience with this system? Problems? My Builder inclination is to nail the fire out of everything. But the radiant guy tells me this system is more efficient than the sleeper approach I'm thinking about.