Butt Joints in Drywall: The Feathering Trick That Makes Them Disappear

I've made every mistake possible with butt joints. My 2017 attempt used a 4-inch knife, feathered 3 inches on each side, and the seam looked like a raised scar for the entire 11 months I lived there. My 2019 attempt used a 12-inch knife, feathered 6 inches on each side, and the seam vanished. Same wall, same paint, same light. The only difference was how wide I feathered. After 5 butt joints in 3 apartments, the one trick that consistently hides them is the width of the feather, not the number of coats or the brand of compound. Here's what finally worked.

Butt Joints in Drywall: Why They're Different From Tapered Seams

Most drywall sheets have a tapered edge on the long sides — the factory makes these edges slightly thinner so when two sheets meet, there's a small valley that the joint compound can fill and create a flat surface. Butt joints are where the short edges (or the cut ends) meet. These edges aren't tapered, so the compound sits on top of the seam instead of inside a recess. That's why butt joints almost always show a visible ridge after painting — there's just no place to hide the compound.

Three things make butt joints visible:

• Too-narrow feathering — the compound was only spread 3-4 inches on each side of the seam, leaving a visible hump where the seam is.
• Insufficient build-up — the compound is too thin over the seam to hide the edge of the drywall, so the seam shows as a slight depression or line.
• Paint sheen differences — even a well-mudded seam will show if the paint sheen is eggshell or higher. Flat paint hides imperfections; anything else reveals them.

The fix is wider feathering, more build-up, and flat paint. None of which require a pro — just patience and a wide taping knife.

Step 1: Feather and Build the Joint Wide

The first coat on a butt joint is wider than you'd expect. The traditional 6-inch feathering that works for tapered seams is too narrow for a butt joint — you need to spread the compound 10-12 inches on each side of the seam to hide the hump.

What you need:

• 10-inch or 12-inch taping knife (the wide one — this is where it earns its keep)
• 6-inch taping knife (for the first coat)
• Premixed all-purpose joint compound (a quart is plenty)
• Paper drywall tape (1-7/8 inch wide)

The first coat: Lay the paper tape over the seam. Use the 6-inch knife to spread a layer of compound over the tape, pressing firmly to squeeze compound out from under the tape into the seam. Pull the knife at a 45-degree angle to scrape off the excess. Let it dry 4-6 hours.

The wide coat: Switch to the 10-inch (or 12-inch) knife. Apply a thin layer of compound and feather the edges 10-12 inches on each side of the seam. This is the critical step for hiding a butt joint — the wider you feather, the less visible the seam becomes. Pull the knife with one long stroke from ceiling to floor, pressing harder on the outer edge to "feather" the compound to nothing.

Let this coat dry overnight. Don't try to perfect it on the first coat — that's what Step 2 is for.

Step 2: Sand and Inspect Between Coats

Most renter butt joint patches fail because people skip the between-coat sanding. The result is a wavy ridge that gets worse with each coat. A 60-second sanding between coats fixes 80% of the visibility problem.

What you need:

• 150-grit sanding sponge (NOT sandpaper — the sponge conforms to the wall better)
• Bright flashlight
• Damp rag

The sand: Light pressure with the sanding sponge, just enough to knock down the high ridges and any trowel marks. Hold the flashlight parallel to the wall, pointing across the seam — the shadow will reveal any high spots or low spots you missed. Wipe with a damp rag to remove all dust.

The big mistake: sanding too hard. You want to knock down ridges, not sand through to the tape. If you see the paper tape showing through, you've gone too far and need another coat of compound over that area.

Apply a second wide coat with the 10-inch knife if needed (most butt joints need 2-3 coats total). Sand between each coat.

Step 3: Final Coat, Prime, and Paint With Flat Sheen

The final coat is what determines whether the seam is invisible or obvious. This step also includes paint choice — sheen matters as much as the mudding.

What you need:

• 10-inch or 12-inch taping knife
• 220-grit sanding sponge (for the final pass)
• Damp rag
• Drywall primer (small can, Kilz or Zinsser)
• Flat finish wall paint matched to your existing color
• 9-inch roller frame with 3/8-inch nap cover (NOT a brush — brushes leave stroke marks)

The final coat: Apply the thinnest possible coat with the wide knife, feathering 12-14 inches on each side. This is a "tip pass" — the knife should barely touch the compound as you pull it. Let it dry overnight.

The final sand: Use the 220-grit sponge with very light pressure. You're just smoothing out any remaining trowel marks. Wipe with a damp rag.

The prime: This step is what makes the joint disappear. New joint compound absorbs paint differently than the surrounding wall, so unprimed patches show as a different sheen even when the texture is perfect. Roll a thin coat of drywall primer over the entire patched area plus 6 inches on each side. Let dry per the can (usually 1-2 hours).

The paint: Use FLAT finish, not eggshell or satin. Flat hides the slight unevenness that's inevitable with butt joint repairs. Eggshell and satin reflect light and reveal every imperfection. If your existing wall paint is eggshell, you can still use flat over the patch as long as the patch is small — the eye won't notice a 24-inch flat section surrounded by eggshell.

Roll the paint in thin coats. Two coats usually blends it in. Let each dry before the next.

When to Stop and Call the Landlord

Three situations where butt joints in drywall go beyond renter scope:

• The seam has a visible gap wider than 1/8 inch — that's a poorly hung drywall job from the original construction, and the fix requires re-taping with setting-type compound that renters usually can't mix.
• Multiple butt joints are visible across the same wall — usually means the original drywall installer didn't stagger the joints correctly, and the fix involves re-mudding an entire wall.
• The seam is cracking along its entire length within a year of patching — that's a sign the framing behind the drywall is moving, and the butt joint will keep cracking regardless of how well you patch it.

The other thing worth knowing: most butt joints in newer apartments (built in the last 20 years) are visible because the painter used the wrong sheen on top, not because the mudding was bad. If you rent an apartment with a flat-painted wall where the butt joints are visible, try this: paint a small section with flat paint (over the existing eggshell, after cleaning) and see if the joints disappear. If they do, the fix was sheen, not mudding.

For everything else — the one butt joint down the middle of a wall, the visible seam above the doorway, the ridge showing where two sheets meet on a long wall — the 3-step plan above gets it done in a weekend with under $20 in materials. None of mine have reappeared, and the worst one is now invisible from 4 feet away.

Settlement cracks in drywall repair guide covers the related fix when the visible seam is actually a settlement crack running along the joint — same toolkit, different cause.

What it actually costs to mud and tape drywall covers the labor math if your butt joint fix ends up being one of several seams that need attention across the apartment.