The house is 400 yrs old with very thick stone walls. Some walls have been covered in plaster and painted, and in some areas this paint has cracked and is peeling. The house is very exposed and in the last few years there has been much flooding in the area, though the house did not flood. The cracking and peeling has mainly occurred around a bathroom window and above radiators. There is also some black staining appearing in corners of outside walls. We are hoping to decorated and will need something that breathes and is hardwearing. We appreciate any suggestions you may have.