Make an in-wall cable duct yourself?

Hello

We have a new building that will be finished soon.

Unfortunately, the developer did not offer an in-wall cable duct.

Can we install it ourselves afterward?
Our wall is 15cm calcium silicate stone + insulation.
Our TV wall is the exterior wall.

If yes, what would you recommend?
How wide and deep should it be?

1 power cable, 4 HDMI cables, and 1 USB cable should fit in the duct.

There are such cable duct elements specifically for that. With us, it looks like this:

A 15 cm wall is already very thin, especially as an exterior wall. But that is not the issue here. Just lay your cables next to each other. Use a grinder or planer and mill a channel 5 cm wide and 1 cm deep into the KS stone. Then glue the cables in the wall with hot glue. The plasterer will do the rest.

The total wall thickness is 34cm.

15cm sand-lime brick 19cm insulation boards

I have already found a multimedia channel about 6cm deep

My question is, can I remove 6cm from the wall afterwards? Or is that too much?

yes, that's what I mean How many cables fit in there with you?

gluing is not an option. The cables should of course remain replaceable.

The different cables have to pass through it

You don’t need a special one for that. Just buy a normal closed cable duct, make 2 holes in the lid and in the wall for it.

But for your cables, you definitely need a proper width and depth, or height of the duct.

Whether you can just cut a slot of 8cm width and 4cm depth in a 15cm load-bearing exterior wall... no idea.
Especially since you weaken the wall even more in that area with the holes for the TV mount...

11cm is no longer a load-bearing wall.

According to DIN, a slit in the wall may not become that large. But please research yourself how large it can be at most. We simply took a flat duct from the kitchen department (6cm deep, 10cm wide) and chiseled out the wall (24cm load-bearing interior wall KS) so that the duct could be plastered in. So far, the wall is still standing and even holds the TV. :) It was no fun chiseling it out afterwards; it would have been better to do it right when building the wall. Alternatively, you could put a narrow drywall in front of the wall!? 50mm profile, simply covered, you lose about 6-7cm of space, but you are on the safe side. (from a structural point of view)

"Vertical slits and recesses -
for 11.5 and 17.5 cm wall thickness - max 10cm wide - from openings 11.5 cm -- basically only 1cm deep
24 cm wall thickness - max 15cm wide - from openings 11.5 cm -- basically only up to 3cm deep
according to excerpt from DIN 1053 part 1."