Drywall panels feature beveled edges on their long sides and flat edges on their shorter ends. Where the flat ends of two panels meet, there is no beveled seam recession, so the joint compound can form a bump over the seam, marring the flat look of the wall. Careful panel layout and butt finishing techniques reduce the problem.
Panel Size and Placement
The fewer butt joints you have to tape, the better. Reduce butt joints by installing the largest drywall panels you can manage safely. Drywall comes in 4-foot widths and lengths of 8, 12 or 16 feet. Where two horizontal panel ends meet on a wall stud, you have a butt joint. By staggering drywall seams, butt joints are less apparent. For instance, if your wall is 14 feet wide and you install one 8-foot panel on the top left side of the wall, you will cut a second panel 6 feet long to cover the rest of the wall. This creates a butt joint 6 feet from the right side of the wall. When you install the lower horizontal row of drywall, put the larger, 8-foot panel, on the right side and the shorter, 6-foot piece on the left side so the butt joints do not line up.
Using Drywall Shims
Drywall shims are very thin strips of stiff cardboard, available in bundles from lumberyards and do-it-type centers. In a technique called “floating butt joints,” the builder staples a drywall shim to the wall studs on either side of the stud on which the butt joint will fall. The shims push the drywall panels out imperceptibly on the two adjacent studs, so the butt joint will be slightly recessed in comparison, although it’s difficult to see the difference with the naked eye. When you tape the joint, however, the slight recession will make the butt joint less noticeable.
Tape and Compound Application
Pros apply thin paper drywall tape over the seams between drywall panels, while do-it-yourselfers often find it more convenient to apply self-adhesive drywall mesh tape. Mesh tape, however, is thicker than paper tape, so if you’re finishing out a butt joint on a visible section of the wall, use paper tape. Apply a thin coat of compound to the seam, cut and apply the paper tape, and smooth it flat with a trowel to force excess compound out from beneath the tape. Let the seam dry before the next coat of compound.
While the taping process for beveled joints and butt joints is the same, butt joints benefit from the use of wider drywall taping knives. On a beveled joint, a 10-inch knife is sufficient to feather out the wet compound, but opt for a 14- or 16-inch knife to feather the compound out over a wider wall expanse when taping butt joints. Sand butt joints thoroughly between coats and after the final coat dries.
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