ᐅ Shower niche shelf made of aerated concrete blocks

Hi, from the beginning we actually wanted to install a recessed shelf in our shower (see picture).

Unfortunately, we forgot this in all the stress.

The interior plaster is already applied, as well as the screed.

Is it still possible to create a niche in the side wall facing the storage room?

It is a non-load-bearing Ytong wall (11.5cm (4.5 inches) block) and with the plaster we have a 14cm (5.5 inches) thick wall.

We were thinking maybe about 70cm (28 inches) long, 30cm (12 inches) high (one tile height), and about 8-9cm (3-3.5 inches) deep.

Would that be possible? Especially since the plaster is already on? And without having to break through the whole wall?

It’s definitely possible. In the end, it’s basically just pulling cables—just a bit wider. The tricky part is that the wall is so thin. You have to be very careful not to break through.
Pick, pick, pick, that’s all I can say.

Smoothing out the rough edges again is probably not a big deal. There are tiles planned for that surface anyway, right?

Hmm, have you asked your bricklayer about this?
We had a niche built elsewhere measuring about 70 x 50 x 10 cm (height x width x depth) and a lintel was installed above it right away. However, I’m not sure if that was only necessary because it was freshly built or if, in general—especially considering the width you’re planning—some kind of support is needed for the stones above to prevent them from settling later on.

No, it is not feasible.

Bau-Schmidt schrieb:
No, that is not feasible.

And why?

Because the wall is simply too thin for that.
With an 11.5cm (4.5 inches) wall, at most a shelf with a depth of 6cm (2.4 inches) is possible, and only then with a lintel.