Ask the builder

Taping drywall is not as easy as it looks on do-it-yourself shows

By Tim Carter
Friday, February 25, 2011; 10:29 AM

Q. Is taping drywall that hard to do? I watched it done on a television show, and it seems like it's not too tough. What tools should I be looking for? What are some secrets of finishing drywall, and what are the biggest mistakes rookies make when mudding and taping drywall? I want my job to look like a professional did it, so please help me out. -Wanda P., Haverhill, Mass.

A. Let me first say that you could ask these questions to 10 professional drywall finishers and probably get 10 different answers. What's more, entire books have been written about the topic, perhaps the best being the "Gypsum Construction Handbook," published by the experts on the topic, the USG Corp

In my opinion, taping drywall is much harder than it looks on the shows you watched. I've done video work for years and can tell you that a talented videographer and editor in postproduction can make the toughest jobs look like a cakewalk. What the camera can't communicate is the muscle control you must exhibit to get the drywall tools to produce professional results.

I had an employee who worked for me for years but was never able to master the art and craft of drywall taping. His results were sloppy, and he'd either leave too much joint compound under the tape or he'd press too much out, allowing blisters to form when subsequent coats of compound were applied. No matter how much training I offered, the results were dismal. I'm convinced the failure was part lack of desire and part a severe shortage of hand-eye coordination.

Here are a few of the most common mistakes I see rookie drywall finishers make. The first is using the joint compound straight out of the box or bucket without mixing it with a small amount of water. The joint compound, or mud as it's called by the pros, must be smooth and have the consistency of warm cake icing. If you tilt the mud pan, it will flow slowly in this plastic state. Avoid adding too much water as it will dilute the adhesive that's in the joint compound.

Remember, joint compound is basically glue and dust. I say this because the compound is designed to stick to the drywall paper and it's made from very finely ground ingredients that turn to dust as you sand them. But make no mistake: Top-quality joint compounds are made to exacting standards.

Another common mistake is not keeping the precise amount of material between the tape and the drywall. I say this because you might wish to use the traditional paper tape in lieu of the self-adhesive mesh tapes. Many a debate has raged between professional drywall finishers about which tape is better, mesh or paper. I happen to use the traditional paper tape and have never had an issue with it.

To get a feel of how small the margin of error is when taping drywall, take a straight-edge or a broad knife and place it across the tapered edges of two pieces of drywall. Note that the gap is no more than 1/8 inch. This means you need no more than a 1/16-inch layer of mud under the tape. This leaves you with a thin coating of mud the same thickness to cover and hide the tape on your second application of joint compound.

It should be obvious that the consistency of the mud must be very plastic if you want to achieve this result. One trick is to be sure that the mud you apply to the seam is no thicker than1/8 inch before embedding the tape. Be sure the mud is even, smooth and without lumps or voids. Embed the tape and run your taping knife across it smoothly with even pressure to press out the excess mud, making sure you leave the proper amount.

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