Make an in-wall cable duct yourself?

I have looked up for you what the rules say about sand-lime bricks:


The effects of vertical (perpendicular) slots in load-bearing and non-load-bearing walls are different. In the case of load-bearing KS walls, vertical slots (regardless of slot depth) are generally uncritical. In this case, the wall can be assumed to consist of two wall sections, separated by the slot.


At the location of the slot, a free edge is to be assumed...., may also be executed in non-load-bearing walls.

[*]For four-sided supported non-load-bearing walls, the vertical slot can be assumed as a free edge. It must be checked whether the permissible wall lengths of the two resulting (three-sided supported) wall sections are complied with.
[*]When determining the permissible wall length of the non-load-bearing wall, the next smaller wall thickness may be used.
[*]When determining the permissible wall length of the non-load-bearing wall, the next smaller wall thickness may be used.

In other words: with an 8 cm wide and 6 cm deep channel, you can calculate as if you had continuously removed 8 cm width from your load-bearing wall....without further consideration, however, only up to 2 cm depth or up to 10 cm width would be unproblematic.

Thanks, I was also going to try googling tonight.

There is (or I haven't found one because I don't know the correct name) no empty conduit or multimedia conduit with the dimensions

Mostly they are 80 x 60mm WxH on the outside

I don't quite understand your statement

The effects of vertical (upright) slots in load-bearing and non-load-bearing walls are different. For load-bearing KS walls, vertical slots (regardless of slot depth) are generally uncritical. In this case, the wall can be assumed to be in two wall sections separated by the slot.

The exterior wall must be a load-bearing wall, so shouldn't vertical slots (regardless of slot depth) generally be uncritical there?

In your table, the max. depth shows the small 2

Slots that go up to max 1m above the floor (would be the case with us, possibly up to max 1.20m, but you could also keep it up to max 1m; the TV is big enough to cover everything)

For a KS wall > 240mm, slots up to 80mm depth and 120mm width are allowed.

Where do they get these numbers? In the table for 240-299 it shows 30mm depth and 150mm width

here is our floor plan

There you go, that's wonderful: I immediately see a first-class option for a partition wall that can even be hidden in a bay window seat.

here is our floor plan

How exactly do you know the precise status of the building services and the position of the pipes to the upper floor? I know a house with exactly the same floor plan. There is a kind of technical duct running up along the right wall, so that either in front of or behind the right window a recess is created. There is also something installed there with meters. A rarely stupid position and not shown in the promotional floor plans. Are you sure it’s somewhere else in your house?

Yes, the technical shaft is in our hallway at the entrance.

Behind the TV or lowboard we only have sockets, LAN, and satellite.

The cables go directly down under the screed.

I took photos of all rooms during the shell construction so I know where all the electrical cables run.

Where the cable shaft is supposed to go, there are no cables running.

The shaft is of course much better off there. I'm happy for you.