Floor construction with wooden substructure

: I prefer the mineral wool variant due to its insulation value and easier handling; the thing with the decoupling mat is probably true if the expert says so. However, in our first house, tiles were glued onto a 22 mm OSB board and only reinforced with a mesh fabric, and that held for the 10 years since the previous owners did it... I will try it that way again.

: Yes, I have also wondered about that and have received various answers here as well; the question is whether the 25 mm boards would provide significantly more stability. Maybe , as an expert, has an answer for this.

: I don’t think anyone is "complaining" here; rather, it’s about getting a good price-performance ratio. Nobody likes to spend more money than "necessary." Furthermore, there were no complaints about the costs of mineral wool as insulation; I only noted that Fermacell elements are too expensive for me and do not offer the corresponding added value in my situation.

Nowhere was it said that no money can or will be spent... Additionally, I wrote in my first post that the old construction (meaning the floorboards have already been removed and now the 12 cm reinforced concrete raw ceiling is exposed). Otherwise, I wouldn’t even have the 11 cm height difference.

And my initial question was (and still is) whether I should screw and glue the OSB boards onto the 6x8 cm batten timbers or not?

Maybe you have an answer to that without addressing nonexistent problems. Thanks

The superstructure is screwed onto the bearing timbers with Spax screws and continuous threads, tongue and groove are well glued. Do not forget foil laid continuously, overlapping at the edges of the strips, under the bearing timbers.
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Regards: KlaRa

Thank you for the reply, that is exactly what I wanted to know. I also found something interesting on Google, basically exactly the structure I planned and as confirmed.

I have attached two screenshots related to this.

And then I found a table on the manufacturer's website of an OSB panel manufacturer regarding the spacing of the substructure, which I have also attached. According to this, my spacing combined with the thickness of 22 mm should be sufficient.

Hello everyone.

I had asked a similar question elsewhere - unfortunately without much response.
In the meantime, I have almost made up my mind.

Are the joists really not screwed to the floor underneath? I have a tiled floor underneath. Therefore, I would have also omitted a vapor barrier foil - the tiles actually take care of that. (And if I screw, it doesn’t matter anyway)

Or is it better to have it floating on both tiles AND foil?

I have planned 50*38 squared timber under a 25mm OSB panel. With insulation wool in between.

Hey,

unfortunately, I can't help you with your question regarding the vapor barrier. But as far as I understand, decoupling is prevented by screwing into the floor, since you are basically "connecting". This naturally causes all impact noise to be transmitted directly through the screws into the tiled floor.
In the screenshot of the installation instructions posted above, it is also shown to stick an edge insulation strip under the floating laid battens. This, together with a surrounding edge insulation strip, ensures maximum decoupling.

It is also important that you do not use screws to fix the OSB boards into the battens that are so long they might penetrate through the batten and reach the tiled floor.

Thank you. My concern is less about the noise (it worked before, usually no one lives downstairs and the finished floor also has impact sound insulation), but much more about problems with water and mold...