I need to bring in intake air to what will become a new laundry room located below ground (souterrain). The exterior wall is made of light concrete (30 cm) and externally drained with Platon. Outside, there's a "patio" with a concrete wall filled with sand (like a sandbox) with paving stones, so my plan is to dig down into the sand (about a 40-50 cm deep trench), then make a hole in the exterior wall and in the concrete wall of the box, lay a 110mm pipe between them, and then refill the sand.
The question is, how do I best seal the pipe penetration in the exterior wall where the pipe exits (I was thinking of using a 110mm ground sewer pipe)?
The question is, how do I best seal the pipe penetration in the exterior wall where the pipe exits (I was thinking of using a 110mm ground sewer pipe)?
Foam, simple and still not visible. On the inside, you can carve out a bit once it has hardened and tidy up with plaster if you have it on the walls today.