Concrete the terrace - connection / thermal separation of the building

Hello everyone,

we are currently considering whether to pour a separate concrete slab for the terrace as part of the house construction.

How exactly is the separation/sealing done in relation to the building?

The building's concrete slab ends with the perimeter insulation and is sealed with a sealing slurry.

Is the terrace slab now poured directly against the building's concrete slab and the perimeter insulation simply made thicker?
Or is there actually "air" left between the two slabs?

A discussion with the shell builder is still pending; I just want to inform myself about the topic in advance.

In terms of height, I would plan to stay about 10 cm below the finished floor level to still have enough options for the terrace surface.

The slab will of course be constructed with a slope, and the substructure will be frost-free.

Thank you very much.

How thick is the current perimeter insulation on the house? I see that as absolutely uncritical as long as the two floor slabs do not touch each other. I would place a separation strip between the floor slab of the terrace and the perimeter insulation of the house, but only for the inner perfectionist. I do not see any extensive measures as necessary here. The floor slab of our garage was even poured directly up to the floor slab/bricks of the house without a separation strip and without any additional sealing, etc. Afterwards, I thought a separation strip would have been great for impact sound insulation. It remains to be seen whether we will hear it in the house every time the garage door opens and closes.

But again, I would place a separation strip there; the terrace floor slab would then have nothing to do with the house, neither physically nor thermally.

*Edit:
You do not have to seal the terrace floor slab itself, just use appropriate concrete and ensure a frost-proof substructure.

The perimeter insulation would need to be 10 cm thick.
By separating strips, do you mean e.g. another perimeter insulation?

Also, in my opinion, the topic of drainage channels in front of the floor-to-ceiling windows plays a role here:

- Drainage of the channels via area drainage: Here the concrete slab would necessarily have to be brought up to the house?
- Drainage of the channels by connection to the rainwater pipe: Here there would necessarily have to be a gap between the concrete slab and the house, as otherwise I could not connect the channels to the pipe.

What are the experiences here? The channels with area drainage are sometimes really extremely expensive. Which variant is usually used here?
The second alternative would also have the advantage that at least at these points you can access the rainwater pipe again.

The perimeter insulation should be 10cm thick. By separating strips do you mean, for example, another perimeter insulation?

The topic of drainage channels in front of the floor-to-ceiling windows also plays a role here in my opinion:

- Drainage of the channels via surface drainage: Here the concrete slab would necessarily have to be brought up to the house?
- Drainage of the channels via connection to the rainwater pipe: Here there would necessarily have to be a gap between the concrete slab and the house, otherwise I could not connect the channels to the pipe.

What are the experiences here? The channels with surface drainage are sometimes also really extremely expensive. Which variant is usually used here? The second alternative would also have the advantage that you can at least get to the rainwater pipe again at these points.

A separating strip is basically the same as what the screed installer installs along the wall. He primarily does this so as not to transmit impact sound to the wall.

We also chose facade drainage with a connection to the soakaway pit. As I just mentioned in another thread, for protective reasons and also a bit to keep normal precipitation away from the basement as much as possible because we justifiedly have only limited trust in the WU construction (in our specific case).

Yes, there are channels that simply drain into the surrounding areas and are practically a replacement for the gravel strip at the facade, and there are channels (Aco, Anrin, etc.) that are connected to a KG pipe and drain into the sewer, the soakaway pit, the cistern, or infiltration trenches, etc.

We laid all the pipes for drainage in the ground when building the basement. This would also be conceivable for you. The KG 2000 pipes last at least as long as your terrace floor slab, so I wouldn’t worry about that. Lay them so that in the end only the channel has to be installed. By the way, these are also installed in concrete and not just buried in sand. If you leave a gap, simply add 1–1.5 cm to the channel body for the separating strip, then you are on the safe side. Depending on the model, the channels can even be connected on the narrow end, which makes retrofitting really easy.