in floor heat?? without floor insulation

[herk]

Hello has anyone put in, in floor heat ( hot water ), without foam board in the floor?? In my dairy barn milk room and parlor I put 2 inch foam board with the water lines stapled to it, then 3 to 4 inches sand then cement , it works well I use a gas water heater. A friend used a water heater for years in his 40x42 shop only replaced because he thought the in side flue was rusting. I seen on YouTube that some people are not putting insulation board down, when I did my barn I think that there was a bubble wrap product some were using , it worked as insulation and vapor barrier. I would use foamboard vertically on the outside walls between cement and outside walls. this will be a farm shop set at 40-50 degrees. thanks Bryan

 

[redforlife]

No insulation, I think would be a bad idea. I don't know that it has to be foam board. But something else used in its place I think would be a must.

I've been told that if no insulation is used, the heat will absorb into the ground (down), and not into the cement floor (up). The insulation provides that barrier.

If not done right, the floor heat won't work well. I have heard some bad stories. As in, the floor heat didn't work at all when it was done.

 

[Hoofer B]

Use insulation. Find a different area to save money. Bill

 

[smileykeith]

use the insulation but the sand i do not dojust pour the concreate on the tubes been 10 yrs and works great

 

[sms]

I would use insulation. I have used both, foam and bubble wrap. Definitely should have a thermal barrier. With bubble wrap we put wire down, attached tubing then put another layer of wire, that way tubing didn't float to the surface.

 

[riverbend]

I used insulation underneath and along the edge. Heat rises but it also seeps out along the edges. The savings in propane paid for the insulation many times over.

 

[jaoneill]

This has been debated for years in the industry with no clear consensus as to what the payback period would be for insulating under a slab. However, there is little doubt that it does make difference.

 

[showcrop]

45 years ago I put foam board seconds under a floor. This was before radiant heat was used much. I got factory seconds of foil covered yellow foam. A few days ago I saw stacks of the same product stacked for sale. A search showed "Factory Seconds of Foilback Insulation in 4'x8' Sheets" in Chambersburg PA. Maybe there is a place near you.

 

[Geo-TH,In]

I haven't put heat in the floor.
My basement floor stays around 55 degrees year round.
I have found that using a fan to blow cold air off the floor up to the ceiling warms the floor better than using a ceiling fan.
I have a well insulated 24x24 garage attached to the house. The Floor is on top of pea gravel. Pea gravel acts like an insulator.
The garage will stay at 50 degrees and no heat.
I use a 1500w baseboard heat if I want it warmer..
I would recommend adding more insulation. Cold air settles on the floor.

 

[cjunrau]

In my opinion and from what I know of heat/cold, insulation can be helpful but also useless.
If you have insulation 2-3 ft down around the building and you live where there is no ground moisture seeping up, and the rain water can not get under the floor you don't need insulation.

dry ground does not transfer heat or cold efficiently.
I live on top of a hill and am in sandy loam. water level is 20-30 ft below ground level. code says I need vapor barrier under floor and that is all I have. Works good and no sign of heat getting out and melting snow around the building.
My dad lives where the water is 4 ft below ground and you can see how much cold and heat is moving by how far out from uninsulated floor the snow is melting and frost coming in if you turn the temp down in the building.

he built new and insulated under and down 2 ft around and you can see the difference.

so depends on your soil and drainage in your area if it is worth it.

 

[stevieb49829]

I've done two of them to date. Both on 2 inches of blue-board (EPS), and both with at least 16 inches of blue board vertical along the perimeter. Nothing on top of the insulation except wire, and concrete. I tied the PEX to the wire mesh with zip ties, and lifted it a bit as they poured. Both these floors are wonderful to work on. I built an outside water-jacket wood boiler for it. I've used less than a cord of hard maple this winter, and it has been cold this year. My shop cat won't let me ignore a cool floor. She prefers it at 60-65 degrees. I can get by with 50-55, but not the whiner.

The soil below an uninsulated floor will work as a thermal mass, storing more heat than your concrete can, but it also looses heat out the bottom, to cooler subsoil below. You might not need all that thermal mass to keep your floor where you want it. Insulation is a very stable substrate for a concrete floor. Mine has never cracked. steve

 

[504]

When I poured my the company I bought the pex highly recommended reflective double bubble insulation under the pex. The idea was to send heat up and provide a break between the earth and the floor . They didnt sell insulation, but the pex was 1/2price online over local.

 

[buickanddeere]

No idea why somebody would want to save a little $$$ on insulation and pay much $$$ to heat the plant earth under the floor .
We used insulation under the pool to reduce the heat transfer into the dirt.

 

[Jaden]

My shop floor is hot water radiant heated. Very comfortable. I used the double bubble foil faced product and foam board. Further study shows the foil bubble stuff does not insulate well for conductive heat transfer.(ie., direct contact) It does work well as a radiant heat barrier if there is at least a 3/4 free space on one side of it. I used it on the sidewalls to repel heat from the metal siding in the summer and it works well. Insulating with foam board down as deep as practical along the slab edges is highly recommended.

 

[MarkB_MI]

Insulation around the perimeter is most important. The deeper you go with the perimeter insulation, the less important it is to insulate under the slab. But if you only insulate the sides down the depth of the slab, you need to insulate under the slab as well, as heat will escape under the perimeter insulation.

I didn't go deep with the insulation around my slab, but insulated under the entire slab. I put 2 inches of foamboard along the sides, then put down 2 inches of foamboard under the first four feet of the slab next the walls. The rest of the slab I only used 1 inch foamboard, which was a bit cheaper and allowed me to make the center of the slab thicker.

I don't believe the claims for the bubble-wrap insulation. And I would never put it under a concrete slab, since it has no compressive strength. Use high-density foamboard.

 

[showcrop]

(quoted from post at 20:12:27 01/08/23) Insulation around the perimeter is most important. The deeper you go with the perimeter insulation, the less important it is to insulate under the slab. But if you only insulate the sides down the depth of the slab, you need to insulate under the slab as well, as heat will escape under the perimeter insulation.

I didn't go deep with the insulation around my slab, but insulated under the entire slab. I put 2 inches of foamboard along the sides, then put down 2 inches of foamboard under the first four feet of the slab next the walls. The rest of the slab I only used 1 inch foamboard, which was a bit cheaper and allowed me to make the center of the slab thicker.

I don't believe the claims for the bubble-wrap insulation. And I would never put it under a concrete slab, since it has no compressive strength. Use high-density foamboard.

EcoFoil Ultra CBF Under Slab Insulation, is designed specifically for under slab.