Download PDF version (199.2k) Log In or Register to view the full article as a PDF document.
Q.As a remodeler, I've hung and taped my share of drywall on small jobs, but knee walls and sloped ceilings always give me a problem. I'm never able to get a really straight joint on these irregular inside corners. How do the pros do it?

A.Myron Ferguson, a drywall contractor in Broadalbin, N.Y., and the author of Drywall: Professional Techniques for Walls and Ceilings, responds: I'm not a framer, but the first thing I look at when I'm hanging drywall in these very conspicuous corners is the framing. If it's off, I first do a little shimming or floating over high spots along the edge. After hanging the drywall, it's sometimes necessary to prefill low areas with joint compound so that the seam is reasonably straight.

To tape the joint, I like to use a continuous piece of 31/2- to 4-inch-wide paper tape, since I may have to conceal some gaps in the drywall and adjust the tape to get a straight line. Because I apply compound to both edges simultaneously, I like to work with a helper on longer walls, so that the compound doesn't start to dry before the tape is embedded.

After pressing the tape into place — but before it is embedded — I sight down along the corner as my helper makes adjustments to straighten the tape.

Finally, after embedding each edge, I sight down it yet again, making minor adjustments as necessary (marking the center of the tape first with a pencil line helps make the sighting easier).

Several brands, such as No-Coat (Drywall Systems International, 888/662-6281, www.no-coat.com) and Strait-Flex (Strait-Flex International, 888/747-0220, www.straitflex.com) now offer special tapes that can be used on these difficult, off-angle inside corners. An interesting product I use a lot is Magic Corner (Trim-Tex, 800/874-2333, www.trim-tex.com). Made of vinyl with a rubber center, it's adjustable and easy to get straight, and it also acts as an expansion joint.

With all of these products, applying compound along the center isn't necessary — and with Magic Corner it's not recommended. As long as the tape is applied straight, it will finish straight, because only the edges are feathered in with joint compound.

Another good option I've used is Strait-Flex's X-Crack, an adjustable metal angle that attaches to the framing along the corner before the drywall is hung. The drywall is attached to the metal only along the corner, resulting in a straight corner that floats off the framing, so it's resistant to cracking.

By the way, some people recommend just scoring and folding — but not snapping — the drywall so that the two halves of the sheet bridge the angle. This technique, which doesn't require any taping if done right, can work okay on short walls, but it's not very strong. If the framing isn't perfect, the drywall paper will tear or separate as the board is fastened near the angle. It's also difficult to position a larger piece of drywall without tearing the joint.