I have to lay a sheet floor covering in my kitchen. At the external door next to the door sill a 2" width of the wall cavity which needs to be sealed is showing. The sill partly overhangs the cavity and the inner wall skin has been covered by the floor screed laid to receive the covering. I thought of bridging the cavity with a cement fibre sheet like the ones used to bridge cavities at roof gables., and this, of course, would need to be set flush with the screed. Because of the sill overhang it is not possible to drive in timber wedges which could support a cement fibre strip. Can anyone suggest a solution?
I also considered using expanding foam, but, knowing that this can be a messy job and concerned that it might disfigure the plastic sill, decided against it