I am trying to make our family roon more livable, I am starting with the walls. The previous owners did the dry walling and mudding. It appears he only put one or two coats of mud on. When you look at the seams there are gullies where the tape is and ridges on the outside where he did not sand properly. Here is my problem. He painted over his poor work. How can I fix this and re mud the seams the right way. Thank you!

 

You can pick up where he left off. You can mud and sand over what is there. Then prime and paint. The paint will sand right off.

Hope this helps.