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How to Repair a Large Crack in Plaster || Video :: Using Big Wally’s Plaster Magic + Standard Drywall Techniques



A few years ago we removed a portion of the load bearing wall that separates our kitchen from our living room. While I started this work, the “Other Man” finished it. The Other Man is my playful name for Mrs. Moxie’s (aka my wife Jen’s) partner and friend, general contractor Pete. They did several flips together.

Note: Good pictures of our kitchen in the linked post above. For more on the process of removing that load bearing wall, you can read about some of that work here >> Finishing the Kitchen Passthrough.  For even more on removing load bearing walls, see this article from The Family Handyman >> How to Install a Load Bearing Beam.

* How Did This Plaster Crack Happen?

When the Other Man removed this wall, the plaster immediately above (in our bonus room / playroom) cracked. He did have temporary support in place when he removed the wall, but possibly not enough. That, or it was simply our house over time trying to reject … said surgery.

I wrote about that room here >> Cats, a Mouse and This Old House. While we have used this room as a playroom, we are finally now making plans, and as my daughters are getting older, to reno that room. (The wall’s peach color – honestly, a fail.)

Before we started on this room, I had to repair that large crack in the plaster. A little consuming and actually, it was just one of several plaster repairs I was making around the old house. For this post, I focus only on that large crack and in fact, I made a video about it. It was a blast getting some “assistance” from my youngest daughter Eva, 8.

How to Repair a Large Crack in Plaster (Using Drywall Compound)

Repairing plaster can be broken down into two large parts:

Below the video you will find a complete list of tools used, as well as the procedure I followed.



* Tools & Supplies for Repairing Plaster

Big Wally’s Plaster Magic Repair Kit. Drill Driver. 3/16″ Masonry Bit. Shop Vac. Caulk Gun. Flexible Putty Knife. Easy Sand Joint Compound. Drywall Mud Pan. 4″ Repair Knife. CrackSpot Repair Mesh. Lightweight Joint Compound. 6″ & 12″ Taping and Finishing Drywall Knives.

* Steps for Repairing Plaster

The complete procedure as it appears in the video below (plus some time markers):

  • Securing the Plaster (aka using Big Wally’s Plaster Magic) – 1:15
    • Remove Loose Plaster with a Putty Knife
    • Drill Holes 1 to 2 inches away from the crack
      • You’re trying to drill into the Lath
    • Vacuum Dust from holes
    • Squirt Conditioner into the holes
    • Add Adhesive to each hole
    • Install Washers in some holes
    • After setting up (overnight), Remove the Washers
  • Finishing Repaired Plaster – 3:59
    • Mix and Apply powder-type Joint Compound
    • Add CrackStop Mesh
    • Apply a Bed Coat to the CrackStop
    • Skim Coat the entire repair
    • Sand
    • Prime



It is the first time I worked with Big Wally’s Plaster Magic, a set of products that (from what I can tell) are sold exclusively online. The Big Wally’s system came highly recommended from past contributor and historic restorationist (is that a word?), Jason Whipple.

If you view some of the pics in the video, you’ll notice that I had previously repaired a crack in this location. The nature of plaster I guess and the reason for the white areas on the wall before I even begin working my repair. Big Wally’s, in a way, was like bringing in the big gun(s). My review – it was an easy system to work with and it was an essential part of a repair that I feel should hold up for many years to come.

* Help Building Moxie Buy New Drywalling Knives

Also in the video, you’ll notice my somewhat rusty knives that some have commented on. They work all the same, but if you wanted to help us buy new knives *grin*, you could purchase yours here – by way of Amazon. (We make a small commission on each purchase.)

Tip: For a simple way to protect your knives between uses, perhaps a squirt of WD-40.


That’s it. Hopefully it helps, and hopefully you enjoy the video.  While I use a podwer-based Easy Sand drywall product US Gypsum, plaster itself could be used just as effectively. (Purists would in fact suggest it.)

I love your likes and I would love if you subscribed to our channel >> Building Moxie on YouTube. For updates throughout repairs like this, find us on Facebook >> Building Moxie on Facebook.

While I once created a guide for The Home Depot‘s Pro Referral Network, here is post from This Old House for more on How to Repair Plaster. Thanks. ~jb

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