The old building wants to be decorated simply, with white walls. Do you need to shovel the wall and scrape putty again? Can I draw directly on the original basis?

After shoveling the wall, you need to scrape the putty again, because if you brush directly on the original basis, the water solubility of the two materials is different, and the temperature will drop when it changes, which is worse than not brushing! Scraping putty and painting mainly depends on the seasonless weather, about 5-6 days in spring and summer, and 4-5 days in dry and high temperature weather in autumn.