Horizontal sealing of the base slab

@ "joho78": Tip: Save the money for the alternative sealing (the correct term), as no success can result from it! Because the installations that run over the raw ceiling must be secured against slipping. This means: inevitable drilling into the floor slab, through the sealing. This perforates it and it cannot fulfill its intended functions. Whoever does not listen and wants to install a sealing on a DIY basis must simply live with the disadvantages later! Because at a later time, the mistakes made now can no longer be reversed. -------------- Regards: KlaRa

I'm not entirely sure what you mean, because we are now applying a so-called [Spritzbitumen] over the already installed pipes, where of course nothing will be drilled into anymore (the installations are already drilled and screwed to the floor slab). Best regards

@ "joho78": A liquid seal cannot be applied properly in the case that empty conduits or installation pipes for sanitation have already been attached/laid on the floor slab. The same applies if the installations are to be carried out after the application of the alternative sealing (liquid seal)! If you write: "... I don't want to take any risks here ..." then this planned approach is by no means suitable to prevent the risk of later damage and/or an unfavorable indoor climate (because it is always damp) caused by moisture rising through the floor slab! You can also ignore these cautionary words, but when it comes to STRUCTURAL ENGINEERING as well as SEALING, expertise in building physics is required and not information that one can read from a container label in a hardware store!! But you decide. I myself do not write these lines because I am bored and my need for recognition drives me to put something on paper. I write these lines rather because I know the disadvantages from my expert practice, from which I would like to protect you. Because sooner or later exactly what I have predicted will occur. And because then there will be no possibility for you to correct a wrong path. -------------------- Regards: KlaRa

Hello KlaRa! Thank you very much for your explanations and believe me, I appreciate your opinion, otherwise I would not have asked the forum for advice! Furthermore, I work together with professionals in this regard (e.g., building physics calculation by our architect), but I also like to get other opinions.

So now back to the question: What is, in your opinion, the technically optimal sealing against rising moisture (water vapor diffusion)? Best regards

Hello "joho78".
Just so much: I also advise architects when it comes to structures in flooring. Even then, when (as happened) a big project was poorly planned, so that from outside one could look through the floor-level window panes into the cross-section of the screed...
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In your case it is now probably only about damage limitation.
Presumably (but that would be for you to check) the bottom rows of stones of the interior and also exterior walls are not sitting on a horizontal barrier (if not yet plastered, the edges of the waterproofing membranes can be seen there).
That means: even if one waterproofs the entire surface in the current construction state, in this case rising moisture would come up through the edge areas of the walls.
But: no need to panic.
If the current situation is that a concrete slab in contact with the ground is already equipped with all installation lines and the interior walls are standing, one can only work with a foil waterproofing (sheet material) which is overlapped sufficiently at the sheet joints and glued watertight and vapor-tight with a suitable adhesive tape.
Although this looks “forbidden” and involves difficulties in laying the thermal insulation boards (impact sound can be neglected when executed as described), this is the only way to "steady the ship".
The weak point then lies in the floor/wall transitions, where the waterproofing layer must actually be connected to the horizontal barrier following the rules of the trade.
Primarily, the question must be clarified: horizontal barrier on the masonry (first or second stone row) present, YES or NO.
All solution approaches with a liquid waterproofing are doomed to fail in the starting situation, as proper processing of the material and in a defined, continuously accessible layer thickness is not possible!
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Regards: KlaRa

Hello KlaRa!

Thank you very much for your invested time! Regarding your questions: Yes, the first row of stones is everywhere provided with horizontal waterproofing (bitumen). I will now forward your comment to our architect, as the sprayed bitumen layer is only planned for the end of next week and thus theoretically (if not sensible) can still be "stopped." I am curious to hear what he has to say about it.

Thanks

Best regards
Jochen