When you discovered that a standard sheet of five-eighths-inch dry wall weighs 73.6 pounds, you wisely decided not to try to muscle the 32-square-foot sheets to the ceiling of your new room addition. Better to pay a professional. Then, you reasoned, you could save a few dollars by taping the room yourself. Taping is the process of concealing all seams between panels with joint tape and joint compound, as well as burying corners and fastener heads in the same ”mud,” a material of a buttery consistency that dries to a smooth, hard finish.
No matter what you call it-wallboard, gypsum panels, dry wall or USG Corp.`s trade name, Sheetrock-you`ve chosen a construction material (or more appropriately, a building system) that has effectively revolutionized the construction industry. The dry walling of interior spaces in new construction has virtually supplanted the classic plaster approach.
While almost everyone appreciates the assumed quality of plaster-the solid thud when you rap on the wall and the greater sound-shielding capability-very few people are willing to pay the price for it. In addition to being the clear choice economically, dry wall is not difficult to install and finish, and most important, it results in a smooth wall surface that rivals the appearance of plaster.
So your room has been ”rocked,” as the professionals (called rockers)
refer to it; all wall and ceiling surfaces have been covered with gypsum panels that have been glued and screwed to the walls. Gluing and screwing dry wall to the studs has become a popular alternative to nailing because it assures a tighter bond and reduces nail popping. This is a failure that occurs after new timbers season following construction. As the wood dries and shrinks, nails are forced out and actually pop through the surface of the dry wall. Screws are not subject to this condition, but some tapers feel just the reverse happens: The screws get sucked in as the wood dries and a ”pucker”
or indentation results.
Before thinking about taping you must make sure corner bead has been installed. This is an L-shaped, perforated strip of galvanized steel, sold in 8-foot lengths, used to reinforce and protect outside corners. Make sure all nails or screws are recessed below the surface of the dry wall so that they can be concealed in the finishing process. Finally, make certain no drywall paper tears or ragged panel edges are exposed.
The capital investment required before you tape is minimal. All you need is joint compound, tape and a few tools.
Joint compound or mud is a combination of calcium carbonate, limestone, water and additives that serve to bind, thicken and preserve the resulting product.
”Basically, there are two types of joint compound, a drying type and a setting type,” says Van Perrine, a product manager with Chicago-based United States Gypsum Co. Perrine says USG is the nation`s largest manufacturer of gypsum panels, with 35 percent of the market.
Perrine describes the drying type of compound as one in which, after application, the water evaporates, usually within 24 hours. It comes in two forms, ready-mix and powdered. The ready-mix version is clearly the most popular because it is so convenient to use. It comes in 4 1/2-gallon containers weighing more than 60 pounds and in roughly gallon-size containers weighing 12 pounds. The powdered version comes in 25-pound bags and is selected principally by professionals, says Perrine, who notes this form of the material is still popular in Chicago.
There are three kinds of drying-type compounds, according to Perrine:
– Taping. This material is used primarily for embedding tape and as a first coat for corner bead and nail heads; it adheres well to the wall surface and shrinkage is minimal. It does not sand as easily or as smoothly, however, as . . .
– Topping. This is a smooth-sanding compound that can be used for the second and third applications. It is not recommended for use in embedding tape, however, because it lacks the bonding power of taping compound.
– All-purpose. Definitely a choice for the do-it-yourselfer, this material combines the desirable capabilities of the other two. Out of one container, you get both taping and topping compound. All-purpose compound bonds well and is not difficult to sand.
A recent development by USG offers an even better approach. The ready-mix product is called Plus 3 Total, and like its all-purpose predecessor it can be used for taping and topping. The difference is it weighs about 35 percent less than conventional materials.
”A key feature is Plus 3 shrinks so little, only two coats are needed over screws and corner bead instead of three,” says Perrine. He adds that the stuff has become an instant hit among homeowners and tradespeople alike.
Setting-type joint compound dries chemically, which enables it to dry at a controlled rate. USG`s product is called Durabond, a powdered material sold in 25-pound bags. There are six versions, the differences being the drying time for each. Durabond 20, for example, is formulated to chemically dry within 20 to 30 minutes, with an effective working time of less than that-say roughly 15 minutes. So if you don`t work fast, the material will dry rock-hard right in your mud pan.
Durabond 20 is great for filling deep holes quickly or for small patch jobs. Slower-drying versions are Durabond 45, 90, 150, 210 and 300. These controlled-drying materials are designed for finishing in one day. Additional benefits: It offers a hard base for embedding tape, it resists shrinking and edge-cracking, and it is less affected by humidity than the drying type of joint compound.
Because it dries so granite-hard, Durabond is murder to sand. And there is no ready-mix version. You must prepare a small batch at a time and use it all up immediately. If your phone rings when you are using Durabond, don`t bother answering it.
Joint compound is an inexpensive material to purchase. USG`s Plus 3 retails for about $12 for a 4 1/2-gallon pail. Durabond 20 is less than $7 retail for a 25-pound bag.
The only other consumable supply required is the tape itself, and two versions are available.
Conventional paper tape is 2 inches wide and comes in rolls of varying lengths, according to Chet Borys, a manufacturer`s representative for tools and building materials based in Orland Park.
Paper tape is scored in the middle to facilitate easy, accurate folding for installations in the angles where walls meet walls and where walls meet the ceiling. Paper tape comes either plain or perforated (to allow penetration of joint compound and provide superior adhesion of tape to wall surfaces).
A recently introduced self-adhesive fiber glass tape needs no embedding coat of joint compound.
”Drywall jobs for the homeowner are cumbersome, and fiber glass tape helps eliminate part of the work,” says Borys. ”It saves the time it would take to put on an extra coat of compound. It is easy to apply and lowers overall material costs.”
While there are advantages to fiber glass tape, Bill Carlander, a professional taper from Wauconda, is not among the proponents. ”I recommend it only for small jobs-like a patch, or for repairing large holes in walls,” he says.
Fiber tape is easy to lay down on flat joints between panels, Carlander acknowledges, but it is tricky to install in angles because, unlike paper tape, it does not come with a crease. He also warns that adhesion problems crop up under dusty conditions and that the tape can fray, making it difficult to coat with joint compound.
The cost of tape won`t require you to refinance your home. A 36-foot roll of fiber glass runs $2.35; 300 feet costs $9.89. Paper tape costs even less:
75 feet retails for about $1.65; 250 feet costs $3.55. (Prices are retail estimates from Borys.)
Just a few tools are needed for taping. Borys says a mud pan is a must. This is a plastic or stainless steel tray to work out of as you apply the mud to the wall. A do-it-yourselfer mud pan is about 12 inches long and about 4 inches wide. The tray`s lips should have stainless steel blades to make it easy to wipe your taping knives. Never work out of an open pail, because the material will dry up. The plastic tray described costs less than $5.
Then you`ll need at least two sizes of taping knives. The pros recommend three-6-inch, 8- or 10-inch and 12-inch stainless steel blades. For good-quality equipment, the total cost for all three knives should be less than $30.
Whether you are doing one room or a whole house, taping can be very intimidating and tedious. Carlander, who started in the trade in 1972, has come up with a philosophy for approaching the task.
”I have a routine, and I always approach the processes in the same order,” he explains. ”It is very Zenlike. Only concentrate on what is in front of you at the moment-don`t worry about the rest of the project. Concentration and confidence are important in anything in life, and taping is no different.”
Carlander prefaces his explanation of taping by offering a few definitions: A corner is an outside edge where two walls meet. An angle, as described earlier, is an inside edge where two walls meet or where a wall meets the ceiling. A joint is where the tapered edges of two drywall panels meet.
To start the job, Carlander first prefills any gaps at joints or angles to provide a sound base to accept the taping coat, the first application of material in which the tape is embedded. He says he often uses Durabond for this step because of its quick-setting property.
Using a 6-inch knife, Carlander spreads the taping coat to about the depth and width of the recess of the drywall joint (formed by the tapered edges). Starting with the joints, he applies compound from ceiling to floor and then lays in the tape.
Pull down with the scraper on about a 45-degree angle, he says, so that the joint compound squeezes out from behind the paper. ”It is very important to wipe the paper down flat so that no air bubbles are trapped below the tape,” he warns.
Proceed around the room until all joints are taped, then start on the angles. Apply compound in the same manner. Cut the paper to the length necessary and crease to form a 90-degree angle. Push paper into the angle with your fingers, and then smooth the line with the edge of the knife. For both joints and angles, the paper tape should be fully exposed when the taping step is complete.
Next, coat the corner bead (if the room has a corner). Start at the ceiling line and apply compound toward the center of the corner, using an 8-inch knife and working both sides of the corner alternately. When you reach the middle, stop and go to the floor and work up, and blend the two wet edges when you hit the middle.
Finally, coat the nail or screw heads with a layer of compound. Let everything dry for 24 hours.
Before applying the second coat of compound, called the bed coat, Carlander recommends a light sanding to knock off any ridges of material and to smooth high spots. Although joint compound does not contain asbestos, it`s a good idea to wear a particle mask and safety goggles while sanding.
Now, using an 8-inch knife, Carlander ”doubles out” the joints by widening them to about 8 inches. He uses the same feathering technique to blend the edge so that the seam disappears. At this point, the paper should be buried in joint compound. He proceeds around the room in the same order described above.
Here`s a basic technique for applying compound. ”Flatten the knife as much as possible (at least a 45-degree angle to the surface) and apply more pressure to the outside edge of the seam,” Carlander says. ”This will feather the edge, and help make the seam disappear.”
The final application of compound is called the skim coat. Using a broader knife, 10 or 12 inches, widen the joint again, several inches beyond the previous edge. Do the same for corners and nail heads.
There are two problem areas to be extra cautious with: patches and butt joints, or the point where two untapered panel edges meet, generally the 4-foot sides of two panels. Such joints must be spread wide because in the absence of a manufactured recess, a hump appears when the tape is embedded. Therefore it is necessary to widen such joints to 20 inches or more.
Ceiling work is critical. ”Light does not bend, so you will easily see the shadows of any imperfections in your work. The key is to widen joints as much as possible to mask problem areas,” Carlander explains.
When the skim coat is dry, sand all surfaces that have received compound. Use 120-grit paper or screen mesh. Feather all edges, taking care not to damage the uncoated paper surface of the dry wall. For best results, Carlander recommends pole sanding the ceiling, followed by spot hand sanding with a sanding block, and hand sanding the rest of the room, also with a sanding block. If you find any mistakes, recoat with compound and sand again.
Although the manufacturer says joint compound can be ”wet sanded” with a sponge, Carlander never does this. ”Wet sanding is a theoretical concept, not a practical application,” he says.
If all of this seems like too much work, Carlander recommends that you contact your local material yard or the painter`s union local for information about locating a qualified taper. For USG`s latest brochure on hanging dry wall and taping techniques, write the company at 101 S. Wacker Dr., Chicago, Ill. 60606-4385.
