Styrofoam, load-bearing as flooring

[addee]

Planning to lay granite and water-based underfloor heating on a 10cm reinforced concrete slab (basement floor below). Have purchased 50mm expensive "floor polystyrene", as well as reinforcement.

Is it enough if I float 45mm on top of this?

The order is:
1. Polystyrene
2. Underfloor heating
3. Reinforcement
4. Float 45mm
5. Granite

 

[addee]

No one has any comments?
Best regards/ A

 

[Mikael_L]

Without really knowing, I spontaneously think that 45mm of self-leveling compound sounds like a lot (and expensive too!).

Then you'll also get a fairly slow-regulating system; are you planning to have granite tiles on top as well? Isn't it possible to lay the heating coils between the self-leveling compound and the granite?

If I understood correctly, you have a basement below?, so the heat loss downwards is not completely wasted money.

I hope you get better answers from someone more knowledgeable.

 

[addee]

Yes, it's going to be expensive... :'(
But the plumber said that the underfloor heating + plastic channels make up 30, and the reinforcement is 5-7mm and then there's "only" 13-15mm left to cover on top of the reinforcement and underfloor heating.

There will be granite, 9mm.

But I hear what you're saying, alternatives?

 

[PjS]

You may not have to use self-leveling compound for the entire thickness but only as leveling; for the rest, you can probably cast in concrete. I'm not quite sure about that, but it might be worth checking out.

PjS

 

[PjS]

Check out tex ardex EB2, admittedly an expensive concrete but cheaper than self-leveling compound.

 

[Larsa]

Hello
I'm not an expert, but it seems like a strange construction. If you are going to lay styrofoam and then tile on top, you need to have a stable base for the tiles. I haven't heard of "casting" with reinforced self-leveling compound. It should probably be a reinforced concrete slab on the styrofoam, and in that, you also cast the underfloor heating. Then, if needed, you can use a self-leveling compound for a few millimeters to even it out before laying the granite.

But as I said, I'm not an expert, I could be wrong.

 

[saturnus]

It's not possible to perform miracles, addee, constructing a floor with a self-leveling compound is a poor design. If I (and others) have understood you correctly, you have 100mm from the existing floor up to the finished floor. Since you want to do the best regarding heat loss downward, you first use 50mm XPS. What remains is 50mm - 9mm for the granite = 41mm...
ha ha, yes, it's indeed very tight for the concrete. I would advise you to place the heating pipes on the XPS and the reinforcement on top of the heating pipes. I would probably take a chance on ready-mixed concrete with fiberglass as reinforcement (talk to the concrete station).
It probably won't take more than 1 cubic meter. And then lay it out and float it as you go, so you get a finished surface for your granite slabs.

 

[elmannen]

Mill down the heating loops into the frigolit... it's a crappy job but works fine with a handheld router.........reinforce and cast with real concrete.........then you'll get a floor that lasts

 

[saturnus]

mill down the heating coils into the styrofoam...it's a crappy job but goes just fine with a hand router.........reinforce and cast with real concrete.........then you'll have a floor that lasts

But...you shouldn’t insulate the heating coils from the concrete, that's what happens if, as you suggest, you mill slots in the styrofoam and press the heating coils down there. Then it would have been easier to go for thinner styrofoam. The heating coils don’t significantly affect the durability of the concrete slab.

 

[addee]

What does this look like, difficult with floor 1?

Floor 1 (basement below)
Needs to be raised 11.6cm in the hall
Needs to be raised 11.6cm in bathroom 1

50mm frigg
reinforcement + underfloor heating
41mm casting
15mm leveling compound
10mm for adhesive and granite

Floor 2 (floor 1 below)
Needs to be raised 17.8cm in the kitchen

50mm frigg
70mm casting
reinforcement + underfloor heating
33mm casting
15mm leveling compound
10mm for adhesive and granite

Floor 2 (floor 1 below)
Needs to be raised 17.8cm in the bathroom

100mm frigg
reinforcement + underfloor heating
48mm casting
30mm for slope (leveling) as well as granite and adhesive

 

[Snurre]

Agree with Saturnus that you should absolutely not mill down the underfloor heating pipe into the foam. Instead, embed it in the concrete and try to level the concrete surface as well as possible. The foam is just supposed to prevent the heat from the slab (radiator) from causing too much heat loss downwards. If you do a good job with the casting, you might not need to level at all.

 

[tomtletare]

How does this look, difficult with floor 1?

Floor 2 (floor 1 below)
Need to raise 17.8cm in the kitchen

50mm Frigg
70mm casting
reinforcement+underfloor heating
33mm casting
15mm self-leveling compound
10 mm for adhesive and granite

Floor 2 (floor 1 below)
Need to raise 17.8cm in the bathroom

100mm Frigg
reinforcement+underfloor heating
48mm casting
30mm for slope (leveling) and granite and adhesive

What is the existing bjl between floors 1 and 2?
Pouring 5-7 cm means you add 120-170 kg new load on the existing floor?
Can the floor really handle that and still have the capacity to bear an additional 200 kg as the standards say households should be able to handle?

 

[addee]

There is 10cm of concrete between 1 and 2. Probably reinforced (encountered reinforcement in the bathroom on the same floor).

Maybe lay 10cm of frigg instead of 5cm to pour less?

 

[Snurre]

Then there can be problems with even heat distribution with waterborne underfloor heating in a slab that is too thin. The effect can be that you can feel where the heating coils are located, warm above the coil, cooler between the coils.