Base plate with concrete core activation. What is your opinion?

The term concrete core activation sounds great, but in my opinion, it is mainly a marketing component. Of course, in the case of underfloor heating in concrete, it is the latter that warms the concrete itself. For any other underfloor heating in screed, one could also say screed core activation or for a wall heating in the bathroom, lime sandstone, plaster, and tile core activation. It just doesn't sound as good and hasn't become established. Why it is called that for the floor slab, however, is something to consider.

Interesting thread. I keep wondering whether a classic underfloor heating system is meant to be embedded in the base slab here under the label "concrete core activation" (instead of the usual practice of embedding it in the screed above). Or whether the components of a single-family house are meant to be thermally "activated" here (cf. concrete core activation in Wikipedia).

So what is it about?

I used the term because I am of the opinion that the Schwedenplatte and Futura use this concept. I did not want to specify a single provider and therefore used the term concrete core activation.
However, I also find it difficult to distinguish the term as you just did. I understand that you don’t simply place the underfloor heating in the concrete and not in the screed, but also use the concrete as a storage medium. In addition, with concrete core activation, you can also use the walls, but I am limiting myself here to the base slab and possibly now also the ceiling (climate ceiling).

Does this answer your question, or how do you understand it?

I’m not quite sure what you’re getting at right now [emoji4] You need as much insulation as the thermal protection certificate requires for this building element. Whether on the panel or underneath, it’s basically the same to achieve the thermal insulation value. Traditionally, insulation is mainly placed on the panel, under the heated screed. That is cost-effective because it can be manufactured from EPS, and the heat from the underfloor heating goes upward rather than downward. Insulation is also installed under the screed of the upper floor (I think usually 6-8cm) so that the underfloor heating there heats the upper floor instead of overheating the ground floor through the intermediate ceiling.

Yes, that’s clear to me [emoji23]

But good insulation in the floor is crucial because

1. you NEVER get access to it again later
2. better material isn’t that much more expensive and
3. losses are higher since a higher temperature level is present here due to the underfloor heating.

I once roughly calculated with the U-value calculator. Here I get a value of 0.25 with 2cm EPS (impact sound insulation, I didn’t know better) and 8cm aluminum-coated PUR.

The Swedish panel comes out ahead here.

I’m not trying to achieve anything here either, just find the discussion interesting.

I still don’t understand it
2cm plus 8cm is worse than what exactly? The Swedish panel is insulated with XPS, WLG 035. If they use, for example, 20cm of material for it, the insulation value is of course better than with equivalent material (although PUR is better) at half the thickness. The question is, at what price?

I just looked at our thermal protection verification. The heat losses through the panel account for about 8% of the entire building. U-value of the component 0.164.
The U-value is deliberately so low because the client’s requirement was to get as close as possible to KFW 55. For the last decimal place, insulating the floor slab is a nice means because the increase in insulation there is relatively inexpensive. Insulating the exterior wall 2cm thicker or giving the windows better glass influences the transmission heat loss of the building much more, but is also more expensive.
Limit value for the transmission heat loss (H‘T) for KfW 55 in W/(m2k) = 0.292. Planned is 0.291 thanks to the somewhat over-insulated floor slab.

You can also put 20cm PUR under the screed and place the floor slab on an 80cm thick foam glass gravel bed. Then you have a U-value of 0.05, so that is clearly the best...

Moin Moin

I have worked on about 60 - 70 single-family houses with "Schwedenplatte" and installed the same in my own house as a DIY project.

Here are some impressions and experiences.
Of the houses built, I can only remember one that had significant problems with the flatness of the surface. My own is not perfect but also without flooring.
Impact sound is not a problem in any of the houses.
In my own, I have 250m2 of floor space including the garage. I would not do that again like this.
When the trolley jack is moved or a hammer falls on the floor, noises are transmitted.
The insulation can only be compared on specific examples. I like that there is no connection from the building side to the ground.
Also, with insulation thicknesses of 10 - 20 cm, it is not yet the end.
Lumpi’s statements about "Schwedenplatte" and solid houses are wrong. Heavy constructions are also possible. It’s all a matter of the compressive strength of the slabs.
Precise planning, working and measuring are important though.
I am not aware of any damage to the underfloor heating. I do not install couplings in the concrete.
The interface between the heating engineer / floor slab manufacturer is completely trouble-free.
Those who are concerned about drinking water installation then lay it in empty conduits.

Olli