Which screed is suitable for my new building?

Hello "tumaa". You should not fall into the opinion that you have landed in a "confusion forum" here. Here is a professional opinion on your topic: As long as you do not provide a barrier-free shower in the bathroom, at least the shower tray does not consist of a prefabricated (and therefore watertight) system element, you can use either a cement screed, a conventional calcium sulfate screed (CA), or a CAF (flowing screed) throughout the entire living area (including the bathroom)! Between the different living rooms, with cement screeds and conventionally installed CA screeds, a movement joint (which goes completely through the screed structure down to the insulation layer) should be formed; with flowing screeds, it depends on the room geometry. For heated screeds, a movement joint should also be provided! The price difference between cement and CAF flowing screeds almost cancels out, since the latter is laid in somewhat thinner layers (thus cost-reducing). What should not be done in a residential building: combining cement screed and CAF. This is simply due to the necessary effort for the screed installer, as both screed types require different mixing and pumping techniques. Please quickly forget that CA or CAF do not need to be skimmed, as this is technically incorrect! Because this is not (only) about surface flatness, but also about uniform absorption in relation to (water in) the adhesive when bonding coverings. With CAF, the screed leveling compound does level itself, but it must be “troweled” immediately after laying – and these “trowel marks” would be immediately visible in backlight with a bonded elastic covering! You see: the topic is not so simple to answer reliably with a "thrown-in" short answer. Greetings: KlaRa

The company was recommended to us by several other trades as a good screed installer. The contact so far has also been quite pleasant. Whether he can really lay the cement screed that well will probably only become apparent afterwards... But it seems that the cement screed is sufficient and good for underfloor heating with a heat pump, so we will probably go with that.

We have cement screed everywhere. It was processed cleanly, no leveling compound was necessary. In the living room, solid wood planks were glued down, so not an optimal flooring for underfloor heating. The flow temperature of the heat pump has so far not been over 25°C, room temperature is 22.5-23°C. I wouldn't know what could noticeably work better with anhydrite screed.

Thank you for the experience report! Then I hope that it will work just as well for us and that we can lay tiles and parquet without having to do much leveling and smoothing.

You can definitely mix cement and anhydrite in a single-family house. However, it has the disadvantage that you have to dry heat twice differently. I wouldn't do that anymore. Always use only cement and that's that.

It is indeed possible to mix cement and anhydrite in a single-family house. However, it has the disadvantage that you have to dry heat twice differently. I wouldn’t do it anymore. Always use cement and that’s that.

Please always read the texts in the answers carefully! I had written in my answer: "What you shouldn’t do in a residential building: combine cement screed and CAF. This is simply due to the required effort for the screed layer, as both screed types need different mixing and pumping techniques." This clearly does NOT mean from my text that these binder types cannot be combined. Smaller screed companies specialize either in cement or calcium sulfate. Large companies can afford to maintain both necessary application (pumping) techniques. But just as it is uneconomical for a poured asphalt company to produce an area of 10 m², it is uneconomical for the builder to bear the naturally higher incidental costs for the binder combination cement/CAF. But I think the builder "tumaa" already understood my objection at that time correctly!