We have original tiled floors on the ground floor. The tiles are not flash to the wall and there is an area of approximately 1.5cm that is covered with some other material. This material looks different than the rest of the plaster above it, a mixture of the original plaster and patch cement repairs over the years. I have removed most of it in preparation for installing woodfibre internal wall insulation. In some places the gap has significant depth (a few cm deep). Underneath the tiles there is some form of Victorian solid floor and because of high ground levels (in the process of lowering them) that edge between the tiles and the wall is always damp. Does anyone know what is the best material to use to fill the 1.5cm gap prior to this insulating? I assumed that it needs to be different to the lime base coat used for the rest of the wall above.