Base plate, what must be considered

Hello everyone,

we are considering building a half-timbered house and have now had the first appointments with various half-timbered house specialists. Over the weekend, we tried to compare the construction descriptions of the providers, and the differences already start with the foundation slab....
Two offers include an energy-saving foundation slab including underfloor heating. According to internet research, a so-called Swedish slab is considered energetically good.

Another offer is a bit more detailed, but according to my understanding, it doesn't go in the direction of the energy-saving foundation slab, does it?

"The foundations are made of concrete of the required quality class according to static requirements, assuming a soil pressure of 0.20 N/mm² and existing soil classes 3 to 4, executed according to DIN. All around, a foundation made of galvanized strip steel according to VDE regulations is installed. The base is made according to DIN 18195 in waterproof reinforced concrete or waterproof fiber-reinforced concrete. Alternatively, for an additional charge, a horizontal insulation in the form of an overlapping and welded bituminous sealing can be installed."

How do the two variants affect normal living later on? Does it take longer for the heating to get warm when turned on, or is the energy input into the ground simply higher?

What is the state of the art, and can one say how much more an energy-saving foundation slab costs?

Best regards and thanks

These are all nice advertising statements.

Even the standard 08/15 cast slab becomes an "energy-saving floor slab" with insulation underneath and/or on top. Energetically all the same. Everywhere the same sluggish underfloor heating inside. And whether it takes 4 hours or 4.5 hours for a slight temperature change to occur, in the end, it doesn't matter. Only regular radiators (with high flow temperature) are fast.

Foundation made of galvanized strip steel

I would really like to see that. (It probably means the foundation earthing, but that only shows how much the descriptions are focused on marketing and less on technical details.)

On the other hand

Alternatively, for an extra charge, a horizontal insulation in the form of an overlapping and welded bituminous seal can be installed.

would not be "nice to have" for me but rather "must have". If the floor slab builder doesn’t do it, someone else has to install it.

Hello and thanks in advance,

@ ->The building description mentions foundation grounding, seems to be an autocorrect error ;.)

-> Could you briefly explain to me what is meant by the "...horizontal insulation in the form of an overlapping and welded bituminous sealing"?

In any case, call the electrician immediately for grounding, as they must document and confirm the correct execution.

-> Could you briefly explain to me what is behind the "...horizontal insulation in the form of an overlapping and welded bituminous sealing"?

This means that a thick foil (bitumen membrane) is basically laid on the concrete floor slab and the individual sheets are welded together so that no water can penetrate from below through the floor slab into the walls. I would never build without it, unless it is a treehouse or on stilts.