Leave the floor slab over winter

Even with a prefabricated house, the interior construction takes its time (screed drying, etc.)

There is also dry screed, etc.

The winter does not affect the concrete slab as long as the concrete had enough frost-free time to reach its initial strength (21 days). So it is better to pour concrete in October than in January. (although with additives it is also possible to work in freezing conditions).

By the way, construction drying in winter has nothing to do with the lower humidity but is a special property of water that transitions directly from solid to gas, thus drying out the building (sublimation). The story with colder and better drying air is related to another physical point: the relative humidity. The warmer the air, the more water it can absorb. If I now bring cold air into a building and warm the air with geothermal heat, it can absorb more moisture, which is why a closed heated building dries faster in winter than in summer. This can be easily tested. Put a hygrometer into an airtight box and place it in the freezer. Then the humidity rises continuously... then take it out again and the humidity drops again.

By the way, a well-known problem for mold at thermal bridges happens exactly because of this. The wall surface is colder, the warm air flows past, cools down and reduces its capacity to absorb water -> condensate forms on the wall and mold grows.

Thank you very much for your answers

Winter does not affect the base slab as long as the concrete has had enough frost-free time to reach its initial strength (21 days). So it’s better to pour concrete in October than in January. (although you can also work in frost conditions with additives).

By the way, drying the building in winter has nothing to do with the lower humidity but is a special property of water. It changes directly from solid to gas phase and thereby dries out the building (sublimation). The story with cold and better drying air depends on another physical point: relative humidity. The warmer the air, the more water it can absorb. If I now bring cold air into a building and the air is warmed by ground heat, it can absorb more moisture, so a closed heated building dries faster in winter than in summer. You can easily try this: put a hygrometer in an airtight box and put it in the freezer. Then the humidity rises continuously... then take it out again and the humidity decreases again.

By the way, an old well-known problem for mold at thermal bridges is exactly this. The wall surface is colder, warm air passes by, cools down and reduces the capacity to hold water -> condensate forms on the wall and mold grows.

Initial strength of 21 days? Have never heard of 21 days.

Maybe the thread starter and you should inform yourselves at betontechnische minus Daten.de to avoid writing such half-truths again.

Our goal/plan is to move in in March or at the latest April.

Do you have that in writing? That will be a very tight squeeze, if not impossible: the interior finishing takes just as long as with solid construction. Or will everything (including screed) be dried on your side?

: thanks for the note. Quote 'For the assessment of concrete strength and frost resistance, the 28-day compressive strength is generally decisive.'