i recently bought a 1930s house that has been completely re skimmed now 18 months on every wall has Cracks and hollow noises when tapped Except those walls that were plasterboarded. My question is would the house have lime render / plaster that has been skimmed with modern gypsum plaster hence why it has cracked or could it just be the original render has perrished over the years and need replacing? (Just find it strange that it's all walls and is getting worse month by month - new plaster has been applied correctly as its I have taken off are firmly stuck to original