ᐅ Which type of foundation slab/construction method to choose and what to watch out for!

Hello,

I have a few questions regarding slab-on-grade foundations for house construction.

We are now slowly entering the quotation phase and planning a single-family house without a basement (in NRW).

I am assuming it will be a conventional concrete slab, as I have too little information about the so-called Swedish slab.

No underfloor heating will be installed.

However, I am reading about different possible layer structures for this topic.

Therefore, my question here is: what should the optimal setup of a conventional slab-on-grade foundation look like?

Regarding insulation, I have read that it is possible to place the insulation both above and below the slab (is this practical?).

Furthermore, I am wondering if it is correct that simple PVC sewer pipes are no longer permitted and that a multi-utility connection system must be installed for slab foundations without a basement.

Is bitumen membrane or a product like Knauf Katja Sprint installed after the shell is completely erected, or is it applied earlier directly on the slab?

As a layperson, I am trying to gather as much information as possible in advance about the work processes.

Thank you very much for your support.

Axel

Traditionally, foundation trenches are excavated at the base level and filled with concrete and reinforcement steel. The walls are later built on these strips. Then, the entire base area is shuttered and covered with steel mesh reinforcement. Concrete is poured on top and allowed to cure. The formwork is removed. Done. Before pouring the concrete, however, the ground workers install the supply and drainage pipes using KG pipes, which now protrude from the concrete. In Schleswig-Holstein, a multi-utility connection is not mandatory; in our area, gas, electricity, water, and telecommunications enter the utility room via empty conduits or KG pipes.

The bricklayer then applies a bitumen membrane onto the concrete as a moisture barrier and builds the walls on top of it. Once this is complete, he covers the floor areas of the rooms with a welded bitumen sheet using a gas torch. Electrical cables and water pipes are then laid on this bitumen layer. Thick EPS insulation boards are installed on top, and separated from the walls, the floating screed is poured. Finally, tiles or leveling compounds and floor coverings are installed on the screed. Okay? Karsten

Big thanks to @Nordlys

For us at SH, having multiple trades involved was mandatory.

Here, having a multi-utility connection is mandatory.

What heating system do you plan to use if there is no underfloor heating?

Concrete slabs can be constructed in various ways—none is necessarily better than the others; it depends on factors such as the type of house, soil conditions, topography, and so on.

- As Karsten described: strip foundations with a non-load-bearing slab and insulation either above or below
- Strip foundation acting as a frost barrier with a load-bearing slab and insulation either above or below
- Bedding and load-bearing slab with insulation either above or below
- Uncommon variants

@Nordlys the capillary break layer, membrane, and possibly insulation are missing.
A multi-service conduit prevents the intrusion of pressurized water. It makes no sense at all for a slab-on-grade foundation!!!!! However, some utility providers now require it. Just imagine it technically: if the water rises 10 cm (4 inches) higher, it will still flow right into the front door.