Radiant heat under 2 subfloors?

[muncybob]

When we had our game room addition put on several years ago the contractor messed up on things and the sub floor wound up being too low in relation to the existing structure...so his correction to this was to install another layer of subfloor to even things out. I wish I had thought far enough ahead and planned for radiant heat before installing the carpeting and pool table!! Now I wonder if it would be worth my effort and $$ to run another zone of pex between the floor joists of this area? This zone is already equipped with baseboard heat and it works fine, but radiant appeals to me. With 2 subfloors and fairly heavy wall to wall carpeting...will I get any real heating benefit? Any adverse effects to the subfloors from receiving the pex heat? Last thing I want is the two subfloors to be expanding or contracting due to the heat and wind up with creaking floor!

 

[pelletfan]

No you will not get any real benefit that way.
There are other alternatives to solve your problem.
Take a look at the Radiant Flooring Heating System Guide
http://www.finaltouchinteriors.com/...mments/radiant_flooring_heating_system_guide/
it's quite selfexplanatory.

 

[Willman]

Don't know your sub floor thickness. Check out the many options for in floor install of tubing. Product such as warm floor or others. You can use lower temp water for in floor versus under floor. Id be shy about two layers of sub floor as well as carpet with underfloor. Nothing as nice as floor radiant. Except ceiling install.
Will

 

[tom in maine]

You might pull it off, depending on how thick the subflooring is, but the carpeting is probably the kiss of death.
You did not mention how thick the subfloor was. Anything that is over 1.5" thick wood is an issue.
The heat load is another factor. If the heat load is higher, it is difficult.

To try to make a marginal situation work, you need to have a higher insulation value under the floor than the surface you are trying to push heat up through (bubble wrap users--Take Note).

After all this, put in some radiant panels and forget the floor!

 

[BrownianHeatingTech]

...put in some radiant panels and forget the floor!

Ditto. With what you're fighting against, panel radiators will be much easier, and give many of the same benefits.

Joe

 

[muncybob]

Each of the subfloors is 3/4" thick. I wish I would have known more options available to me when it was being installed! The floor panels you refer to are a type of flooring? I've seen subfloor with grooved channels to take the water piping...is this what you are referring to? I can't add anything to the top of the floor without removing a very large & heavy pool table...not to mention all the w/w carpeting. I am toying with the idea of taking up sections of the carpet, using a router to make channels in the subfloor to accommodate some tubing and then re-stretching the carpet back down. I'm not sure how feasable this will be though with all the nails into the subfloor!...and this may be a lot lore work than I really want to do unless the comfort benefits are going to be so much greater than the current baseboards.

 

[atlarge54]

I've got pex in the floor with 135 degree water temps. Above it is carpet, pad, 3/4 plywood and 3/4 sheeting below is 1" air gap, 1/2" foil faced foam and R19 fiberglass. Surely a less than ideal setup but it was installed in a 50 yr. old home. It seems like with newer construction you should be OK. Do you plan on doing your own install? If you do it yourself don't hesitate to buy a Milwaukee "Hole Hawg" drill bit. I purchased a Zurn manifold and wasn't too impressed with overall quality. It works ok but has lots of straight threads that were difficult to seal during pressure testing. The ball valves don't work very well either.

 

[Willman]

The floor panels you refer to are a type of flooring? I’ve seen subfloor with grooved channels to take the water piping...is this what you are referring to?

Yes, there are a few different products out there. Would require a tear out of one subfloor to eliminate height issues. Not certain about routering grooves because of nails as well as the aluminum contained in the ready made product.
Panels are prolly gonna be your best bet considering what your up against.
Will