Sound insulation of a downpipe passing through the living kitchen

Hello dear forum,

about two weeks ago, we (my family and I) took over our new single-family house from a developer near Lüneburg.

Now that we are slowly moving in and the kitchen will be delivered soon, we noticed that a downpipe in the exterior wall of the living kitchen might not be very well soundproofed.

Above the living kitchen is our bathroom. When we visited the house in the shell construction stage back then, I noticed that a downpipe runs through the kitchen in the exterior wall into the floor slab.

The pipe first goes down vertically about 20 cm, then about 70 cm horizontally, and then vertically again into the floor slab. I seem to remember that the pipe was white, and something about a “soundproof pipe” was mentioned. According to my research, it could be a Skolan pipe.

The pipe is partially wrapped in a red casing and fastened with nail strips – which probably increases the sound transmission, right? Also, I am pretty sure that the horizontal part is just a normal, gray HT pipe and not a white, soundproof one.

When flushing the toilet upstairs, it sounds like water is rushing through the whole wall downstairs in the kitchen. Could this have been better insulated? And would you see this as a defect?

Looking forward to your opinions!

Best regards

We also have that in the renovated kitchen - however, almost only at a height of 100 cm, meaning:

- above that are the wall cabinets
- below are the countertop and the base cabinets

In front of that - in the old kitchen - there was a pull-out pantry, so you basically didn't notice anything. Now it's these 100 cm (or however high it is), it doesn't bother me at all when the flush is up there.

Could this have been insulated better? And would you consider this a defect?

Yes and no. Since I assume you have a guest WC downstairs and therefore rarely go to the toilet upstairs when it is completely quiet downstairs, it wouldn't bother me that much either.

Wow, thank you all for the quick replies! So I understand that you wouldn’t take any further action there.

Just out of curiosity: How could one have properly insulated that?

Wow, thanks for the quick answers! So I understand that you wouldn’t take any further action.

Just out of curiosity: How could one have properly insulated that?

- use soundproof pipes - soundproof pipe clamps - insulation around the pipe with high density (e.g. mineral wool like Rockwool Conlit 150U - these are pipe shells) / alternatively, Armaflex also works (unprofessional, but works) / if boxing or space is available, alternatively fill with mineral wool

It is important that decoupling from the walls is done as much as possible. Regular pipe clamps or nail strips are counterproductive.

The pipe first goes down vertically about 20 cm, then about 70 cm horizontally and then vertically into the floor slab again.

That is also a planning mistake...

Just out of interest: How could one have insulated that properly?

The best solution is not to plan the sewage pipes through the living space.