Now, there’s a couple different ways to approach when you skim coat a ceiling or walls. You can either skim only the seams and corners or you can do it the right way and apply a thin skim coat to the entire surface area, all while taping off seams and corners after you apply the first thin coat.
I would suggest the later. Because, if you want a true “smooth” surface, then you need to coat the entire panel; then go back and sand to a smooth finish. If you don’t, it’s possible to get a light texture in some areas, which will leave an ugly, non-uniform look.
No one wants that.
My Method: How to Skim Coat Drywall
After doing this for so many years, you get a bit set in your ways. So, I use lightweight joint compound, for almost anything, besides drywall texturing. On the walls, I tend to start in the upper corners, then working my ways towards to the middle, then down. I apply it thin, with my trowel at an angle, while working in an ‘X’ motion, then wiping it off.
If you do it right, the paper should hold onto some mud in the small texture features of the drywall paper. If you aim for getting a thin, uniform skim coat, it will be much simpler to sand out imperfections. And don’t make the mistake of working in the dark. You need a powerful shop light to help you see every little detail in the wall or ceilings while you work. It’s a must when sanding.
Sanding to Smooth
If you’ve learned how to skim coat drywall, you should have a nice, even skim coat on the entire surface area, where you took the time to apply a thin coat first, taped seams and corners, then applied the final surface coat to the surface, all while trying to keep it even to make sanding easy.
Now, we can get sanding underway – everyone’s favorite part.
If you’ve got a small surface area, try wet sanding, but if you’re dealing with an entire room, it’s best to stick with some simple manual sanding tools with a fine or medium grit. Take the sanding tool, while applying very light pressure and use your light to see small details.
Have some patience, and take your time. Messing up with newly applied skim coat will cost your many more hours of time going back to apply more compound.
If you want truly smooth drywall finished you need to skim coat the entire surface area. I’ve learned this the hard way over the years. You can do a great job on the seams, but after primer and paint, you’ll see the joints show through. Don’t make the same mistake many have made.
Now, that’s how to skim coat drywall the right way!