How to mud drywall

by | DIY Projects, Home & Garden

This article shows you everything you need to get perfectly smooth walls, without having to worry about nail pops, cracks and bad joints later. I take a beginner DIY approach, so even if you’ve never used drywall tools before, you can get good results on your walls.

Step 1: I started with the easy step: covering the screw holes and smooth the seams.

Having used a drywall counter-sink bit during installation, our screws were already set into the drywall slightly (kinda dimpled in there) making it quick and easy to slop on a bit of mud and scrape it flat. Fill the space between boards with joint compound, making sure to spread a thin layer. It actually wasn’t that hard at all, so it had me thinking I could do this all day…

Step 2: Cover outside corners with joint compound.

Outside corners do not require drywall tape, as they should be affixed with corner beads. Apply joint compound over each side of the bead smoothing it with a single pass of the 125 mm drywall knife.

Step 3: Apply drywall tape to all joints.
Unroll a few feet of tape and position the tape over the freshly applied joint compound covering each joint. Gently press the tape into the joint.

Step 4: Smooth the tape with your drywall knife. Hold the knife against the taped joint at a shallow angle. In one continuous motion, pull the knife across the joint, pressing the tape into the compound. Excess joint compound can be scraped off into the mud box. I used a special 90-degree drywall tool, available at home improvement stores, to fill the corner seam with a layer of mud. Allow all the compound to dry for about 24 hours.

Step 5: Sand the first coat of joint compound
After 24 hours, it was sanding time. You can see in the photo below that my best efforts to smooth everything out with those trowels weren’t perfect and I still had some defined edges that needed to be smoothed out and blended into the wall better. Use a medium-grit sandpaper, and do not sand too hard.

Step 6: Use a 25 cm or 30 cm drywall knife to hit any tapered edges.
Tapered edges are where two drywall edges meet, getting thinner as they meet. This creates a small void on the surface of the drywall. The good thing is that voids are easier to even out with compound than protrusions.

Step 7: After 24 hours sand the second coat of joint compound.

Step 8: Applying the Third and final coat of joint compound.

Once the sanding was done, we could put our third and final finish coat on the walls. A bunch of tutorials suggested thinning out the mud a bit so that it goes on even smoother, so I dumped a little water in and blended it with a paddle mixer. It didn’t make it too much thinner, just about the consistency of mayonnaise.

Tip: Locate the center of the butt joint. On one side of the joint, start mudding with a 20 cm drywall knife.

Once completed, allow 24 hours for compound to dry, and then sand one final time to prep the drywall for priming.


Since that’s not the most exciting picture ever, let’s jump one step further to the primed room. We were so eager to see how our taping, mudding, and sanding held up to the test of being coated with primer that we jumped right on it yesterday. Next up is painting!

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