My calculation went kind of sort of like this: "Assuming the sink is mounted at 85 cm height, the sink bowl itself is 19 cm (according to manufacturer technical data sheet) and the toilet is mounted at 40 cm we have 26 cm minus toilet seat for the knee. This should be okay."
The next email that I received from Angelo was no good news and he sounded furious. Why? After having checked the tiny bathroom he found that the WC can only be mounted at 38 cm height, which is perfect for this case, he also had found that in two other bathrooms the plumber had prepared the toilet pipes far too low and that we would need to reopen the walls for adjustment!
However, one of the bathroom is already completely tiled!
technical data (by Duravit) for our WC
Bad News: toilet pipe installation too low !
You even can see from the picture that the toilet installation on the wall is low. In fact the mounting height would be only 35 cm. (With the recommended 40 cm you have 8 cm between floor and the toilet for cleaning, see technical data picture).
How this could have happened? It's the floor level that had changed tremendously in some of the bathrooms. I think in the green bathroom we raised the floor around 20 cm. Same happened in the bathroom in the basement. Apparently the plumber was not informed about the exact floor level - or the floor level was raised too much ? I think in the basement the later happened since we also planed to have a rain shower in a niche, that all in a sudden became a very low niche ... different story.
This coming week, Angelo will have a word with our plumber and architect. I am curious how to solve the problem. In the basement where the walls are still concrete, it should be no big intervention. And for the green bathroom I hope we do not have to demolish the wall with the SICIS (!) mosaic... If it is only for the cleaning and not for the function, I would probably leave it at 35 cm.
Since I am talking dirty, I mean, toilets, I would like to mention how important some centimeters / inches of a whole in the wall can be regarding WC seating height and comfort! Very important for comfort! In my first renovation back in Germany I had one toilet mounted at 43 cm height. For me it was quiet uncomfortable, since you sit at about 45 cm (including the seat). With the second renovation back in Germany I worked with the same plumber and told him right away for my new WC that I want to have it at 38 or 39 cm. (With the result, that my mob did not go fully underneath anymore. Just a few mm were missing.) So one would think with the 3rd renovation I should have known !!
BTW, in our former home in Beijing and now in Bangkok we have WCs by American Standard (stand alone pieces, not wall mounted) and they have seating height between 37 and 40 cm. Very comfortable. And thinking of the squat toilets, popular around Asia, which my Chinese doctor considers to be more healthy than the Western toilets (he thought digestion wise not hygiene), one should have a WC mounted as low as feasible.