Hi there, we have been renovating our house and have just had our living/dining room reskimmed. However we have around 12 to 14 hairline cracks throughout the walls which have come out. Some straight some all over the place. How can we fix these to ensure they don’t come back? I have gone back to the plasterer who says it just one of those things and they did tape/prep everything prior to the skim. Do we open the cracks up? Will the plaster fall or the walls?! Do we need to put PVA glue in before we fill? What is the best filler? thank you!