Horizontal sealing of the base slab

@ "joho78": That is a very good decision! Because if a horizontal damp proof course was installed below or between the masonry units (this is not only necessary for ground-contacting floor slabs), it also shows that the planner assumed rising damp and wants to prevent the moisture from affecting the wall surfaces capillarily through this measure. I am not a lawyer, but in "case of emergency" (let us hope it will not occur and that the architect – as far as our concerns are justified – will be open to correcting his planning) you may have more than just a good position through this documentation and approach! --------------------------- I personally wish you success in your steps!! Regards: KlaRa

Thank you KlaRa!

Now I would just like to briefly ask one final question

If I can no longer manage the flame-bitumen variant, then the spray variant is probably the better option, compared to not applying any sealing at all, right? A several millimeters thick layer is applied after all, which has a sealing effect, correct?

Best regards and have a nice Sunday!

Hello "joho78". You pointed out in your initial question from January 26, 2017 (quote: "Installers and electricians are currently busy") that at the moment all installation lines are probably already laid and fixed on the raw ceiling. This means that bonding a bituminous surface waterproofing (flaming is only done on the roof) will no longer be possible. For this, a continuously shot-blasted, dust-free by suction and bitumen pre-primed concrete surface is required. These preparations are also needed for a liquid waterproofing. However, these are not standardized and must therefore be classified as special constructions (except bitumen thick coatings, but these are only approved for exterior surfaces) and must be coordinated and approved with the building owner before processing. The planner cannot or must not just apply these on their own! -------------------- The "spray variant," as you call it, is therefore also not usable. Especially since in the described initial situation a thickness check and continuous application (to ensure functionality and tightness) cannot take place at all and cannot be checked either. Such an execution would thus contravene professional rules; you should avoid prescribing or even accepting such a variant!!! What is still acceptable as a functioning emergency solution with installed installations (certainly no honor for the planner) I have already described: Surface waterproofing as sheet material, vapor-tight bonded in the overlapping joints, connection to the horizontal barrier of the wall surfaces. The visual chaos that results after completion of the installation can only be evened out with a bound, water-free filling. On this as a continuous plane, the thermal insulation boards in the calculated necessary thickness, on top PE foil as penetration protection against the mixing water of the wet screed, and on top the 45mm thick screed as standard screed (or at least 60mm as heated screed) are laid. This way, the situation can be controlled as a functioning execution. ------------------------------------ Note: These explanations are not legally binding advice, as I have only taken the local situation from the description. Good luck: KlaRa

Hello KlaRa!

Thank you for the detailed description. I have one quick technical question regarding "surface sealing as sheet material": Since the installations have now been completed and fixed to the floor, is this laid over and glued to the pipes? Shouldn't there be a filling underneath (I understand the need for one on top)? Otherwise, wouldn't a "space" form under these sheets?

Best regards

The membrane sealing is not a stretch film. It can largely follow the unevenness. A filling under the sealing is certainly possible; there is nothing against it. The disadvantage of this design is that the leveling layer/filling must be walked on again afterwards for the installation of the sealing. Unfortunately, this is often done without much care. As a result, uncontrolled footprints usually form by the executing workers, creating indentations in the already leveled filling. Once the sealing is installed above, this level can no longer be accessed for corrections. Smaller indentations should actually not occur, but with reference to the flatness standard DIN 18202 Table 3 Line 2 (for raw ceilings, on which the insulation elements are usually laid), this is rather uncritical. Because ultimately, the thermal insulation and also the screed (the latter due to its thickness) sufficiently and completely uncritically bridge these potential unevennesses. None of this is so decisive as long as the thermal insulation is above the sealing level! So: I have seen both variants, filling above and filling below (with regard to membrane sealing), in practice, and both work. One with somewhat more effort, the other with somewhat less effort.
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Regards: KlaRa

How do you assess the influence of a possible membrane under the base slab (cleaning layer) on the necessity of a horizontal sealing above the base slab? Minor, moderate, or non-existent?