How to flatten uneven wall and ceiling

How to flatten uneven wall and ceiling. Each time you skim it the smoother it get. Don't get discouraged you may have to skim it more then once.

[@madmiata1887]

Adding a 16in knife and a 36in skimming blade to my shopping list. Thank you for the info. Joining old drywall to new drywall causes issues for me.

[@KennyHandymanInvestor]

You welcome and thank you for your support