My new house is 55 years old. I am getting ready for paint but I need help in determining wall and ceiling prep. I believe my walls and ceilings are plaster but without lathe strips. Approximately 1/2" plaster base with approximately 1/8" plaster finish coat is applied to horizontal 18" to 24" high paper wrapped boards.(see attachment) The boards are attached to the studs horizontally and their appearance is similar to wall board. I've been told instead of the meticulous plaster repair procedures the walls and ceiling can be properly repaired with spackling and or joint compound. I have water damage to address in the ceiling, wall hairline cracks, and in one load bearing wall which was raised I have a 1/2" diagonal crack. How to proceed?