How can mold in the shower be prevented structurally?

Hello! In my current house, mold repeatedly forms in the shower. The bathroom is tiled and has a floor-to-ceiling window. Opposite this window, the shower is located in a corner of the interior walls as a niche. There is a man-height radiator on which towels can be hung. The return flow of this radiator runs through underfloor heating. Therefore, the room can be heated sufficiently.

Black mold repeatedly forms in the shower, and I wanted to know how I can prevent this in my new build through structural measures...

You can surely imagine that this is not normal.

Also, you can only prevent something if you know beforehand where the mold is coming from!?!?

- Do you heat too little?
- Do you ventilate too little? If you have just moved in, controlled residential ventilation is not always sufficient.
- Was the plaster/screed sealed too quickly without sufficient drying time
- Do you leave the shower wet after showering?
- etc.

Where does the mold appear? Grout? Tile :-p? Plaster?

There are many reasons that lead to mold. A house is only dry after 3 years, therefore.

If the shower is in a niche, can the steam even properly evaporate? That is probably the cause; you could try whether the problem also occurs if you leave the door open after showering so that everything can evaporate.

As Zaba writes. 90% of mold is caused by too little heating and too little ventilation and 10% by construction errors. A controlled residential ventilation system and a properly adjusted heating system therefore solve 90% of the problem and hopefully the expert on site will solve the remaining ones.

The bathroom is tiled and has a floor-to-ceiling window.

One should use it sometime, that is, open it -> ventilate.

There is a full-height radiator on which you can hang towels.

Towels down and...

The room can therefore be heated sufficiently.

can... can means: does not. So the radiator should also be used sometime -> heat.

3rd rule: after showering, dry the surfaces.

So: in the next house: window on, heating on. If necessary, the shower near the window. Everything else lies in human hands.

3rd rule: dry the surfaces after showering.

You can also overdo it. If the framework conditions are right; meaning there is sufficient heating and ventilation, and there are no thermal bridges or other construction defects behind the shower walls, you don't need to do that.