Any radiant heat guru's out there?

[747mopar]

I'm looking at adding radiant heat to an existing slab then hardwood flooring... tons of options with prices from inexpensive to through the roof. Plan so far is add foam on top of the slab then secure a wood heat panel, either homemade or something like Ecowarm or Warmboard $$$$. Not much info out there on side by side comparisons.

 

[bm02tj]

Keep the water temp down as it will hurt the hardwood
Some where in my books I have the max temp you can run
Are you using real hardwood or engineered wood

 

[moparedtn]

Are you thinking about doing this in your garage?

 

[zyzzyx]

The problem with an existing slab is no insulation underneath. You'll be heating the worms!
Not very efficient.

 

[Toxic Orange 493]

The problem with an existing slab is no insulation underneath. You'll be heating the worms!
Not very efficient.

He said he would be putting foam insulation on top of the slab. My house has radiant heat in the floors and when we were looking for flooring for the basement floor I was steered away from real hardwood. This is because of the how well wood insulates. The engineered wood is ok. For temps you only need between 100-120F. Any hotter and the floor becomes uncomfortable.

 

[747mopar]

Keep the water temp down as it will hurt the hardwood
Some where in my books I have the max temp you can run
Are you using real hardwood or engineered wood

I've got all of that covered, a mixing valve will take care of water temps.
I'm using an engineered floor with a white oak laminate, very stable and top quality stuff... Supposedly ideal for this application.

Thanks

 

[747mopar]

Are you thinking about doing this in your garage?

No, this is going in our living room which sits on a 24×24 slab. Right now it's carpeted but the wife wants hardwood... Perfect time to add a radiant floor system

 

[747mopar]

The problem with an existing slab is no insulation underneath. You'll be heating the worms!
Not very efficient.

Nope... The insulation just goes on top of the slab instead of under it. Honestly the route I'm looking at is supposedly more efficient but one could argue. In my case I'll lay foam over the slab (they suggest 1/2"), next the heat panels get screwed down through the foam and into the concrete then hardwood flooring over it.

The products I'm thinking about use aluminum faced panels, the Pex fits tightly into the panel then the aluminum carries the heat to the surface warming the underside of the floor.

 

[toolmanmike]

Nope... The insulation just goes on top of the slab instead of under it. Honestly the route I'm looking at is supposedly more efficient but one could argue. In my case I'll lay foam over the slab (they suggest 1/2"), next the heat panels get screwed down through the foam and into the concrete then hardwood flooring over it.

And you are talking electric and not hot water. Correct?

 

[747mopar]

He said he would be putting foam insulation on top of the slab. My house has radiant heat in the floors and when we were looking for flooring for the basement floor I was steered away from real hardwood. This is because of the how well wood insulates. The engineered wood is ok. For temps you only need between 100-120F. Any hotter and the floor becomes uncomfortable.

Thanks
My floor will only be 1/2" thick, supposedly carpet is the worst thing you can use since it and the padding are basically insulation.

 

[747mopar]

And you are talking electric and not hot water. Correct?

Hot water, I have a boiler that heats the house and garage. It heats the water to 170-185 degrees (yes, technically not a boiler), a mixing valve is used to adjust the temps within the floor as it's heating loop has it's own pump, thermostat, etc.

 

[747mopar]

To give you an idea of what I'm talking about here's one of the nicer panels out there.

I'm fishing for input on the different options. On one far end you have this company, awesome looking product that I'd jump all over if it weren't stupid expensive! Then there's companies that make an inferior copy, some that are just grooves cut in plywood with no aluminum and others that are foam board which means you'd have to add something to fasten the flooring too. The other option I'm thinking hard on is making my own, I have routers, bits, dado's, etc so that part is a breeze and you can buy the aluminum plates premade that will fit right in.

There's also the sleeper cell method where you frame thin channels under your floor where the Pex heats the air trapped within which then heats the floor.

The problem I'm having is I can see many of these options working really well but without real data which I cannot find I don't know if a product like Warmboard is just throwing money in the trash?


https://www.warmboard.com/warmboard-r

 

[toolmanmike]

Hot water, I have a boiler that heats the house and garage. It heats the water to 170-185 degrees (yes, technically not a boiler), a mixing valve is used to adjust the temps within the floor as it's heating loop has it's own pump, thermostat, etc.

Interesting I didn't think you could retrofit in floor radiant hot water on top of the slab. What kind of products are available? Hot water is usually incorporated into the insulated slab.

 

[mopar 3 B]

At least you should not have to use the expensive for in concrete pex tubing. Have you looked at the insulated panels the tubing snaps into? Takes care of spacing needs and makes those nice radius corners.

 

[Sahara]

We did a house one time where they got these neat floor underlay panels that were like routed in a continuous “W” sort of pattern, faced on one side with aluminum foil. Your water line from the boiler fit neatly into the routed areas. The panels fit together so that the routed parts line up. Worked slick.

 

[493 Mike]

Padding for radiant floors is available as well as low R carpet. My best friend used Warm Board over a plywood sub floor, works great. 1/2" is not enough thickness. Can you use a thicker foam without screwing up your elevations? I have a "staple up" system under my second floor using aluminum heat transfer plates fastened to 3/4" plywood T&G with rubber pad and short weave, commercial carpet. It is very comfortable.
I did several large size radiant/snowmelt systems as a foreman for my mechanical contractor employer back in the old working days.
Mike

 

[747mopar]

We did a house one time where they got these neat floor underlay panels that were like routed in a continuous “W” sort of pattern, faced on one side with aluminum foil. Your water line from the boiler fit neatly into the routed areas. The panels fit together so that the routed parts line up. Worked slick.

Sounds like Ecoboard?

 

[747mopar]

Interesting I didn't think you could retrofit in floor radiant hot water on top of the slab. What kind of products are available? Hot water is usually incorporated into the insulated slab.

Yes, the heated slab has really taken hold and is being utilized everywhere around my parts so naturally the free market saw the need for a retrofit application and voila.

 

[747mopar]

Padding for radiant floors is available as well as low R carpet. My best friend used Warm Board over a plywood sub floor, works great. 1/2" is not enough thickness. Can you use a thicker foam without screwing up your elevations? I have a "staple up" system under my second floor using aluminum heat transfer plates fastened to 3/4" plywood T&G with rubber pad and short weave, commercial carpet. It is very comfortable.
I did several large size radiant/snowmelt systems as a foreman for my mechanical contractor employer back in the old working days.
Mike

Agreed, I'm pretty sure they recommend 1/2" because it's retrofit and they're trying to minimize the thickness. I'm almost certain I'll have to redo my stairs regardless so my plans are to go as thick as possible without reframing doors lol.

 

[bm02tj]

Is this slab on grade and how dry is the dirt under it if slab on grade