Work planning single-family house 180 sqm flat roof with basement & double garage

We are still considering adding a children's bathroom on the upper floor. This means the existing bathroom would become smaller and a children's bathroom (shower, toilet, single washbasin) would be added.

How much additional cost should we expect?

Depends on the equipment and the architect had mentioned 5,000 euros as a rough estimate. Shower, sink, toilet, fittings, additional cost for tiles and sanitary ware are the same.

That means the existing bathroom would become smaller and, in return, a children's bathroom (shower, toilet, single washbasin) would be added.

Are we talking about the design in post #80? - I do see enough space in the main bathroom, but I still lack an idea of a successful layout for two bathrooms. In practice, I consider "children's bathrooms" to be those that end up being cleaned by mom anyway. Water for children is exactly as wet as for adults, and as a family, I find it crazy not to use one bathroom together.

I think it's crazy for a family not to share a bathroom.

I experienced it differently. As a family of four, we all had to get up and go to the bathroom at the same time. If there had been only one, I don't even know how that would have worked.

I experienced it differently. As a family of four, we all had to get up and go to the bathroom at the same time. If there had only been one, I don’t even know how that would have worked.

It worked quite well for us.
Children's bathroom yes or no actually requires a crystal ball.
The usage period is sometimes quite short.

If all else fails, there is often still a bathroom on the ground floor.

I experienced it differently. As a family of four, we all had to get up and go to the bathroom at the same time. If there had been only one, I don’t even know how that would have worked.

"Back then," "people" at "our place" still used the bathroom together, one after the other only in exceptional cases