I have bougth an old 1875 house and during the renovation work we realised that lots of crack are affecting the 1-brick-thick wall confining to the neighbour's wall. I want to make a sound insulation and I'm planning to use plasterboards and fiberflass. The cracks are not affecting the structural integrity of the house. The question is: do I need to plaster all the cracks before I start installin the fiberglass on it ?
Many Thanks in advance for your help,