Sealing the base slab before the roof is installed

Hello,

When is it customary to seal the base slab from above, I mean the timing. The construction company plans to do that before the roof is on. Is that good, then won’t the rainwater stand inside the house?

Regards Daniel

Hello,
I would have the sealing done after covering and before rough installation of electrical/heating.

Kind regards

Thank you for your answer, What disadvantages would I have if it happens beforehand. If I understood correctly, he even plans to seal it first, and then build the partition walls on top of it. That would be fundamentally wrong, wouldn't it? It would confuse me, since he himself is a guild master.

Thanks for your answer,
What disadvantages would I have if it happens beforehand.

If I understood correctly, he even plans to waterproof first and then build the partition walls on top of it.
That would fundamentally be wrong, wouldn’t it?
But it would confuse me, since he himself is a guild master.

Your wall(s) should anyway stand on a bitumen-like barrier sheet and not directly on the floor slab. For us, these were individual strips. Then the waterproofing – after the roof was on – was "glued" on with a torch onto these strips. As a layman, I couldn’t see any significant difference between the strips and the final waterproofing.

He doesn't do that. He probably also puts some black foil under the interior walls and doesn't set the blocks directly on the concrete, but then he'll probably go completely old-fashioned and torch on a bitumen membrane. He can do that on the roof too. You just sweep out that little puddle. Maybe the roof truss factory gave him a late appointment and he wants to make progress. Karsten

In the base slab there are some penetrations that cannot be sealed 100%. When it rains for days, water accumulates on the slab and penetrates under the [Schweißbahn]. It then remains there for several months. The slab is also still damp. Why not let it dry a bit longer?