ᐅ Empty conduit from the utility room to the attic, 50 mm – sufficient

Why should you fill it in immediately? That negates the purpose of a conduit as a reserve.

Airtight only when necessary...

MoeGT schrieb:
A conduit from the service room to the attic is generally recommended, but should it be planned from the start to fill it?
Why not just install the cables in the planned quantity right away?

And mineral wool does not seal; it must be made airtight!

In my opinion, using a conduit makes sense because it allows cables to be easily replaced or additional cables to be pulled through if needed.

We were told that completely sealing the conduit is not advisable. Condensation can form inside the pipes (especially after new construction). If the conduit is sealed, water will accumulate inside.
At least, this was the experience of our electrical contractor. I cannot judge if this is really the case due to lack of personal experience.

At least during the "wet" phase of the interior plaster and screed, I would completely seal off the conduit. We forgot to do this and promptly had mold in the roof structure at that spot because the moist, warm air rose there.

I wouldn’t rely on being able to easily pull new cables later on, unless the cable can be installed without any bends. Still, I would definitely install ALL cables right away and only lay empty conduit as a reserve (possibly with a pull wire). Don’t forget the PE cable for the satellite dish!

Well, I have a 50mm (2 inch) PVC drain pipe plus two M25 conduits (not the flexible cable protection tubes) – they run straight down.

You can always pull things through those.

Our site manager also advised that the empty conduits in the roof structure and basement should be fully sealed with expanding foam. As usual, three experts, four opinions.

I will probably stuff some plastic sheeting in first and then seal with expanding foam. The plastic is to prevent the foam from penetrating too deeply, so that later, if the conduit is used, there isn’t too much to cut away or the risk of foam getting too far inside the conduit.
Does anyone here have a better tip on how to prevent over-expanding foam from going too deep?