Floor heating on an existing slab, does it work?

[Vinterland]

Is it possible to install underfloor heating on an existing slab? The house is on a concrete slab, which is supposed to be insulated and reinforced, but without coils. I am considering laying grooved EPS boards and coils, then installing click flooring or using leveling compound (not sure which is correct?). Anyone with knowledge?

 

[hackatall]

One option is to lay strips of chipboard that are 20-30 cm depending on the loop spacing. Nail them down with a bolt gun directly to the concrete, place heat distribution plates between the strips, and lay out the underfloor heating pipes. The tricky part is managing the loops where they turn, either by custom-cutting the chipboard or casting up to level.

Once this is done, you can either lay a 14mm click floor or another flooring material of that thickness. (You should avoid a 7-8 mm click floor in this kind of solution)

or you can cast the pipe in hand-mixed concrete (reinforced with plaster mesh) but the pipe can be difficult to prevent from floating up.

 

[Vedspisen]

One option is to lay out strips of chipboard flooring that are 20-30 cm depending on the loop distance.
Fix them with a powder-actuated tool directly to the concrete, place heat distribution plates between the strips, and lay out the underfloor heating pipes. The tricky part is organizing the loops where they turn, either cut the chipboards into shape or cast up to level.

when this is done, you can either lay a 14mm click floor or another flooring material of that thickness. (You should avoid 7-8 mm click floors on such a solution)

or you can embed the pipe in hand-mixed concrete (reinforced with mesh), but the pipe can be difficult to prevent from floating.

I have also considered embedding the pipe in a layer of new concrete. But the question is whether you dare to put 100mm of cellular plastic, reinforcement, and pipe, and then pour concrete over it...
I get the feeling that it is worth adding insulation on the existing slab to create effective warmth from the floors, otherwise, there's so much mass that needs to be heated...

 

[Maxwells demon]

The plaster method fits perfectly on existing slab.

 

[Vedspisen]

The gypsum method works great on existing slabs.

[media]

That looked really nice... The question is how stable the floor becomes under stress with only gypsum and a bit of filler?

 

[largab]

Use the EPS system designed for this. There are different systems that build 12-50mm, e.g., LK-systems. I have used their EPS16 on the concrete floor in the basement. The "good thing" is that it provides a short path for the heat upwards with good heat distribution using the AL-covering. If you have space and can allow for a little building height, 30/50 mm is preferable as it allows for a thicker hose.

 

[Vedspisen]

Use an EPS system designed for this. There are different systems that build 12-50mm, such as LK-systems.
I have used their EPS16 on the concrete floor in the basement. The "good" thing is that it provides a short path for the heat upwards with good heat distribution thanks to the AL-covering. If you have space and can allow for some building height, 30/50 mm is preferable as you can use thicker pipes.

Yes, considering using EPS. Should you self-level it or use concrete?

 

[largab]

Yes, considering using EPS. Should I use self-leveling compound on it or concrete?

Eps16, you place the floor directly on it (wood, laminate, tiles). Compound only if you need a slope. Read the instruction manuals for the different systems, available to download as PDFs.