ᐅ The builder wants to apply a bitumen coating to the fully plastered base of the building?

Hi, we are about to receive the house handover soon. Recently, the site manager casually mentioned that we need to apply a bitumen layer on our foundation wall, which is already plastered. This layer should be applied up to the height where the soil will be backfilled.

Another site manager said it should only be applied up to the perimeter insulation.

Since the workers are rarely around and, when they are, they are very brief, we haven’t received a clear explanation on how far we actually need to apply the coating.

Under the foundation plaster, there is pink polystyrene insulation, which was glued on with bitumen (without any sticky, unpleasant black substance).

Do we really have to apply another bitumen coating on top? Or would an insulation coating based on bitumen be sufficient? Or should we use a flexible waterproofing slurry instead?

Everyone says something different -.-

There are so many types of bitumen products. No idea which one is the right choice.

Attached is a screenshot from the contract regarding waterproofing.

I also don’t see anywhere else that anything else needs to be done by the builder.

Here you can see a part of the foundation wall.

I find that strange. Here, during the shell construction phase, they applied two coats of waterproof slurry on the base and up to the height of the first row of Ytong blocks. Then, the base plaster was applied on top. Nothing more was done. That is supposed to be sufficient.

Our plasterers agreed to do it, although it would normally be the responsibility of the homeowners. They were a bit tight on the measurements, so we extended it by a few centimeters up to the planned ground level (splash guard or paving). Then we added a dimpled membrane in front. This is not for protecting the foundation (which has already been covered with bitumen), but to protect the base coat plaster against moisture.

305er schrieb:
I also don’t read anywhere else that anything still needs to be done on site by the builder.

That wouldn’t be necessary if no ground filling was done. That’s probably why nothing is mentioned. However, in our case, it is explicitly stated that this must be done by us.

Do you want topsoil right up to the house? You shouldn’t do that. There should be a drainage system around the foundation, connected to the stormwater sewer. On top of that, backfill with sand and gravel, granite chippings, river pebbles, or whatever you prefer. This way, the foundation stays dry. Karsten

In my opinion, drainage in the splash protection strip is not necessary since there is the foundation bedding underneath, which provides sufficient drainage. However, this probably also depends on the height of the building above ground level and the water table...

But I don’t see any foundation bedding in the picture either. Or am I mistaken? It looks like soil.