Hi all, I am an unwilling renovator! I have an issue with my German style house, comprising of proton blocks, Lime plaster with a porothon ceiling topped with a slab of concrete. One of my issues is that the concrete ceiling appears to be causing a crack in mainly the gable end walls. My first question is - does a inside first floor concrete slab need to have expansion joints in it? The size of the slab ie 14 m x 8 m. Also it appears that the Lime render applied was not suitable for the driving rain in Donegal and that I may have to replaster some sections of the house. I would love some expert advice before I ask local builders who will be unfamiliar with my building materials. Thanks so much for looking here