Hello. I'm renovating an old cottage that has an extension with a basement. I've now torn down the framework between the basement and the first floor because it was moisture-damaged, partly because it had spread from a rotten sill "which has been replaced," but the framework was also built directly against the concrete walls. When I tore it down, I discovered that one of the house walls stands on a cast-out notch, and inside is the basement wall. In between, I can dig down into the soil, so there is about a 4m long and a few cm wide gap that I obviously want to seal before building anew. How would you proceed? Cast the walls together?
