The What and Why of Skim Coating

Before you paint another wall in your house, let’s talk about skim coating. This process of applying a layer of mud (joint compound) to the wall will create a smooth, even surface. When finished, skim coating will effectively conceal all evidence of seams, fasteners or repairs to your walls, even under close scrutiny and under a variety of light sources. 

Why skim coat?

There are several reasons you’ll want to skim coat. Among them: 

  • Covering existing decorative texture treatments to an existing wall
  • Blending existing drywall with new installation for a cohesive look
  • Smoothing out a wall that has been patched and repaired
  • Refinishing walls with lingering wall paper paste or other wall treatments like stenciling and painted patterns 
  • You plan to paint with a gloss or semi-gloss paint that will highlight any defect in the existing wall

What tools are needed?

You may need to apply multiple coats of mud to the wall in order to achieve the look you’re going for. Keep this mind when you’re determining how much joint compound to purchase. You’ll also need a roller brush and a wide drywall knife or squeegee trowel. Pick up a paint tray to hold the mud while you work. Of course, you’ll want to prep your room before you begin to work, so grab a few drop clothes too!

The *How-To* of it all

If you’re working with an existing wall, first make any minor repairs to the wall; for example, fill nail holes and lightly sand any loose pieces. You can also apply a fast drying primer to the wall in order to cover stains, highly pigmented colors or loose wall paper scraps. 

Water down your joint compound to roughly the consistency of a bowl of melting ice cream. You should be able to scoop the mud out of the bucket with an appearance of a lump that’s a little runny and sagging. 

Here’s the key: work in small sections. You don’t want the plaster to dry before you can wipe it down. Using your paint roller, place the mud on a section of wall and then immediately scrape the wall with the trowel. You’ll leave behind a thin layer of smooth mud. Once you’ve completed your first pass, let the walls dry completely. Continue applying layers until the walls are smooth and even. 

One last step: before you finish off your fantastically crisp new walls with your favorite color you’ll want to prime them. This will seal the porous mud and ensure the new paint color you’re looking forward to will adhere to the wall properly.

by Anjie Cho