ᐅ Drain pipe in the exterior wall – KfW55 solid construction house

Hello everyone,

We are building a KfW55 solid house with 36.5 Poroton bricks. Naturally, the sink and dishwasher in the kitchen are located on an exterior wall, which means the drain pipe is planned to run inside the outer wall. The length is about 2.5 meters (8 feet).

Our energy consultant said this would not comply with the energy-saving regulations, but it wouldn’t be an issue for him. The construction company said this is very common in KfW55 houses when it comes to kitchens because otherwise you would need an additional inner wall, which nobody wants in the kitchen. The groove will be insulated to reduce thermal bridging.

Who of you has built a KfW house and placed part of the drain pipe inside the exterior wall?
Did you encounter any problems with KfW or other objections?

Many thanks in advance.

Sternchen31 schrieb:

Were there any issues with the KFW or other objections?

No, no objections from my side.
If your energy consultant approves it, then everything is fine. You’re worrying too much. Everything is great as it is.

It was done the same way for me. Same masonry, also KfW55.

In my case, the pipe goes straight down and out of the house, with no horizontal section running along the wall.

We have routed the ventilation through the roof as well as through an exterior wall.

However, it is a two-layer masonry wall (aerated concrete + facing brick).

But also KfW55 standard!