Make sure the wall surface is clean, dry and free of impurities that reduce adhesion such as powder, dust, grease or wax.
The humidity of the surface should be below 16% according to the Protimeter moisture meter or let the wall surface dry for 21 to 28 days under normal conditions (average temperature 300C, ambient humidity 80%).
Use suitable chemicals to treat mossy surfaces. Use Dulux putty for a smooth surface.
Apply 1 coat of Dulux Interior Primer (A934-75007) for a smooth surface, increased adhesion and long-lasting color for the finish.
Do not mix too much water, coverage and cleanability, washing will be poor.