Laying parquet / Calculating expansion joints

Hello everyone,

we are currently laying parquet, specifically 1500x120x15mm oak plank flooring that is being glued directly onto the screed. On the sides / expansion joints such as to the wall, we have always left at least 10-12mm of space. However, we are not quite sure how to dimension the expansion joint in the door transition between two rooms. Here, parquet lies directly against parquet and there must be the expansion joint in between. Is it sufficient to leave 10-12mm of space here as well, or should this be doubled to 20-24mm total space? We want to fill the expansion joints between the doors with cork strips.

Thank you very much in advance for your feedback!

Here, too, 10-12mm are sufficient.

Ok thank you very much then we can get started :)