Hi renovating 1930s bungalow found that the cavity wall insulation isn't fully completed.This is due to the way the construction changes at all the window points.At windows cavity stops and the external wall becomes a 9in solid brick wall below the window sill which is completely separated from the inner leaf.This wall actually sits on the edge of the internal wall covering the cavity.The inner finish at these points are made up of lath and plaster. Can anyone shed a light on this type of construction.
Thanks