How to Work Around Butt Joints

This story shows how to avoid getting mounded butt joints with untapered drywall.

Butt Joints

Ordinary butt joints are difficult to conceal. That's because the ends of drywall panels, unlike the edges, are not tapered. As a result, you have a seam that's at the finished level of the wall and still requires tape and compound to make it disappear. The risk, of course, is that you'll end up with a mounded joint.

You avoid that by applying a minimal thickness directly over the seam and then working away from the joint with a gradual buildup of compound that makes it hard to see.

But prevention is much easier than cure. You can buy or make inexpensive back blocking products that convert a butt joint into a recessed seam, making it much easier to conceal with tape and compound. If you're a beginner, back blocking is the preferred route because it gives you the best chance of producing a flat wall.

Back blocking isn't just for walls. The technique works well for ceiling panels too. Always use screws to fasten the panels to the back blocker.


Using a back blocker will probably add five or fewer minutes to each butt joint

Power drill/driver or drywall screw gun

Driving screws

Have tools and materials at job site.

Drywall panels, purchased or homebuilt back blocker

Step 1

When you use a back blocker, stop the drywall approximately in the center of a stud bay and slide the product behind the panel. If the stud bay is 16 inches or wider, you'll be able to position the metal legs perpendicular to the center wood strip. If the stud bay is narrower, rotate the metal legs as far as needed to fit.

Step 2

Center the back blocker along the end of the drywall, and drive screws 6 inches apart to secure it. Make certain that your fasteners miss the metal legs. With a pencil, draw the location of the legs onto the face of the panel.

Step 3

Slide the next panel into position, butting it very lightly against the first. Again, drive screws every 6 inches into the center wood strip. Drive a couple of screws through the adjacent panel into the wood strip. In this case, you're not trying to bend the drywall; you're merely anchoring the assembly to the rest of the wall.

Step 4

This overhead view through a butt joint illustrates how the back blocker curves the drywall into the stud cavity. Creating this recess makes it much easier to disguise the butt joint. The straightedge across the drywall shows how the back blocker pulled on the drywall ends.

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