SOS-feeling like this thread might have the answer I need! Skim coating over a really bad knockdown texture. I have done three coats with all purpose lightweight joint compound overall it’s looking pretty good! Only issue is there are still some high point from the knock down still showing through. I don’t think I can sand them at this stage without destroying all the work I have done. What should I do? Additionally, on the walls that look ready. I’ve gone over everything with a light and touched up the places I noticed. I’ve run my hand over the wall more times than I can count to make sure it’s smooth. However, I’m really worried that when I paint sections that aren’t level will be very apparent. Does anyone have any other tips to make sure everything is ready to prime and paint? Would priming the walls and then If anything comes through doing another coat be a terrible idea? It’s been a messy and time consuming process and really can’t wait for it to be over hahah Thankful for any advice!

I'm afraid I can't call the contractor for advice at the moment....he had knee surgery this week. I let the skim coat cure about 10-14 days before priming. I guarantee there was very little humidity during the curing process; Utah is a desert climate and anything above 20% in the summer is considered "humid". I know the walls were free of debris before the skim coating was begun, and I know it's not a problem with the skim coating itself not adhering. When the paint came off with the tape the skim coated surface beneath was intact. I don't have the brand of the compound that was used but I know it was not pre-mixed......my children had a lot of fun watching the compound being mixed in the back yard with the giant "cake mixer" drill attachment. Yesterday I did repair the appearance of the jagged edges where the paint came off by sanding, priming, spackling, sanding, priming, and re-painting and everything looks great now........but I can't help be worried that my careful paint job is eventually going to bubble up and come off the walls.

Bricklock Type S is one option - it has a lot of Portland and is super sticky. Quikrete also makes a stucco finish coat/surface bonding cement (white bag, sold at Lowes, etc) that works really well. When I did the stucco coat on my pizza oven I did a portland-heavy mortar mix for my base coat, and the white bag quikrete for the top coat. That top coat was easier than frosting a cake, and I was able to buff it smooth as glass with a finishing sponge.

Thanks all, it's an attached garage but will not be used for living space. Running new electrical for exterior lighting and car charging, and gas for a new tankless water heater we're adding to the side of the garage (close to the gas main). Sounds like it should all come out and be replaced. I agree that it doesn't need to be perfect, but I think a clean and nicely finished garage doesn't hurt.