How to Plaster over Drywall

Plaster walls aren't built into many homes these days. Most new homes are outfitted with drywall that has been painted and primed. Occasionally, however, a homeowner wants to reinforce their walls with plaster. Maybe that’s what you’d like to do?  Often times the reinforcement is done for stronger walls. Other times, soundproofing or greater insulation is the desired result. For those with a more traditional home décor style, plaster is added to walls to create an Old World texture. Whatever the reason, the process is the same.  Plastering over drywall is not the job for every do-it-yourselfer. It requires patience and a steady hand. In fact, a professional may be best suited for such a task. However, if you’re up for the challenge, make a run to you local home improvement store and get started.

Step 1—Tape All Drywall Joints

Before you can begin to plaster over drywall, you have to make sure that the drywall job is superb. Though plaster is strong and will be on the surface, the drywall is the foundation. If the drywall job is shoddy the finished wall will be too.

If your house isn't new construction and has already been painted, you can lightly sand the wall, fill any holes or grooves, and move on to step 2.

For new drywall, tape all the drywall joints using all-purpose joint compound and an 8 inch spackle knife. The excess joint compound that oozes from below the tape should be applied on top. Once the spackle is dry, even out the surface with sand paper.

Step 2—Apply Chemical Bonder to All Drywall

Once the tape job is dry, you need to add a chemical bonder to the drywall. The chemical bonder is going to allow the plaster to make a strong attachment to the drywall. Because the drywall is covered in paper, without a chemical bonder the plaster could easily fall off. 

Step 3—Apply Base Coat of Plaster

To ensure a professional grade job you need to use professional tools. A hawk and a trowel are customary plaster tools. They can be picked up from your local home improvement store. You should take a few minutes to get acquainted with the tools before you use them. Using a lightweight basecoat plaster, apply a basecoat over the entire wall. Professional plasterers apply this coat 3/8 inches thick. However, follow the manufacturer’s instructions when mixing and applying the plaster. 

Step 4—Apply Desired Finish Coat of Plaster

Before you can apply the finish coat of plaster, you have to mix the quick-set gauging plaster and the lime putty. Using a ratio of 3 parts quick-set gauging plaster to 1 part lime putty, mix the finish coat using a drill and mixing paddle. Most professionals apply a finish coat of 3/16 inch thickness. Refer to the manufacturer’s instructions when mixing and applying your finish coat. 

If you desire a smooth finish on your wall, smooth the finish coat on in the same manner as the previous coat. If you are going to be applying a decorative texture, use your finish coat to create the texture. 

There you have it. You’ve tackled a challenging home improvement job and have the high quality walls you dreamed of.