How to Install Drywall

ESTIMATING MATERIALS NEEDED

• We show a chart for estimating the number of 4x8 sheets of drywall required for paneling rooms of various sizes. If wallboards of any other size are used, make the necessary adjustments.
  
  
• After estimating the number of sheets of drywall required, add another 5 percent for waste.
  
  
• A figure provides tables for estimating the number of nails, the amount of joint compound and the quantity of wallboard tape required for installations of different sizes. (These tables are figured based on the adhesive and nail-on method of applying drywall).
  
  
• For applying the adhesive to framing members from a caulking gun with a 3/8" diameter bead, plan on using eight quart-sized tubes of adhesive for each 1,000 square feet of wallboard used.

   

  HOW TO FIGURE A ROOM FOR DRYWALL

  Perimeter	No. of 4x8 Wallboards Needed
  36'	9
  40'	10
  44'	11
  48'	12
  52'	13
  56'	14
  60'	15
  64'	16
  68'	17
  72'	18
  92'	23

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For example, if your room measures 14x16, this equals 14' + 14' + 16' + 16' = 60 or 15 wallboards required. To allow for areas such as windows, doors, fireplaces, etc., use the deductions listed below: deductions for each:
door : 1/3 wallboard (A)
window : 1/4 wallboard (B)
fireplace : 1/2 wallboard (C)
The actual number of wallboards for this room would be 13 pieces (15 pieces minus 2 total deductions). Always use the next highest number of wallboards when the perimeter total is between ranges shown in the table. These figures are for rooms with 8' ceiling heights or less.

CUTTING DRYWALL

• You can easily cut wallboard with a scoring or trimming knife and a 4' straightedge. You may prefer to use a T-square for an even and straight cut.
  
  
• Measure accurately and make marks before cutting the wallboard.
  
  
• Use a straightedge for accuracy, and score along your marks. Be sure to cut through the paper and into the inner core.
  
  
• Hold the knife at a right angle to the board and score completely through the face paper.
  
  
• The board will break easily at the point where it is scored. After it is snapped, trim the paper on the uncut side with a pair of shears or a sharp knife.
  
  
• Make circular cuts and irregular angles with a keyhole or saber saw.
  
  
• To cut holes in the wallboard for electrical outlets, light receptacles, switches, etc., carefully measure and mark the location of the opening on the face of the wallboard. Outline the opening in pencil and cut it out with a keyhole saw. The hole must be accurately located and cut to size, or the electrical cover plate may not cover the hole.

VERTICAL OR HORIZONTAL INSTALLATIONS

• Apply drywall to leave the fewest possible joints. If the ceiling is less than 8'2" in height, use a horizontal application for 25 percent fewer joints than a vertical one.
  
  
• If the ceiling is higher than 8'2", install the drywall vertically.

APPLYING DRYWALL TO THE CEILING

• Apply drywall to the ceiling at right angles to the joists.
  
  
• Holding the ceiling board in position can be difficult. If you are working alone, solve this problem by making a T-brace from a 2' piece of 1x4 nailed to the end of a 2x4 of sufficient length to reach from the floor to the ceiling.
  
  
• The supporting 2x4 should be about 1" longer than the floor-to-ceiling height.
  
  
• If you are using only nails, nail the board to the ceiling with the proper length of nails and space them about 7" apart.
  
  
• When using the nail-on and adhesive method, use three nails across each wallboard at each joist. Drive one nail firmly into place at each edge and one into the center of the board.
  
  
• Drive the nails in just enough to tighten the wallboard to the framing. Then set the nail with a blow just hard enough to dimple the wallboard. Do not drive the nails hard enough to break the coating paper.

WALL APPLICATION OF DRYWALL

• If the drywall is being applied horizontally, install all top boards first. Push it up firmly against the ceiling–do not force it–and nail lightly into place.
  
  
• In areas where ceiling boards are nailed to ceiling joists, start the first run of nails on the wallboards about 7" below the ceiling.
  
  
• If you're applying the wallboard with nails only, place all nails about 7" apart to all studs. If you're using the adhesive and nail-on method, apply nails only at the edges of the board with adhesive on the back to hold the boards to the studs in the center.
  
  
• If a board tends to bow out in the center, secure it with a temporary nail until the adhesive sets. Remove the holding nail after the adhesive sets.
  
  
• If wallboards are applied vertically, place the long edges of the wallboard parallel to the framing members. Use a vertical application if your wall height is greater than 8'2". Use the same nailing procedures as previously described.
  
  
• Special metal corner strips are available for outside corners. Insert a nail in these metal corner strips about every 5". Nail first through the edge of the strip, then through the drywall and into the wood framing.
  
  
• Use a good grade of joint compound to finish all joints, nail heads and corners. In most cases, you'll need two or three coats of compound at all taped joints. The number of coats depends on whether you are using regular drywall tape or drywall tape that has adhesive on the back.
  
  
• If you are using adhesive-backed tape, center the tape over the joint and press it into place with your knife. Apply two finish coats over the tape. If you are using regular tape, use an embedding coat to bond the tape at each joint. When the embedding coat has set, apply two finish coats over the tape.
  
  
• Allow each coat of joint compound to dry about 24 hours before applying the next coat.

FINISHING TOUCHES ON A DRYWALL INSTALLATION

• Use a 4" joint finishing knife to smooth out each coat of joint compound. Fill in the slightly recessed area created by the adjoining tapered edges of the wallboards and smooth it off with the 4" joint finishing knife.
  
  
• Center the wallboard tape over the joint and press it into place if you are using the adhesive-backed tape. For the regular tape, press it into the first layer of compound firmly, but not too hard. Hold the 4" knife at a 45-degree angle. Press just hard enough to squeeze out some of the compound from under the tape, but be sure you leave enough compound for a good bond.
  
  
• With adhesive-backed tape you can apply the fill coat right away. With regular drywall tape, allow the tape to dry in position for at least 24 hours and then apply a fill coat, extending it a few inches beyond the edge of the tape. Feather the edges of the compound for a smooth finish.
  
  
• After the fill coat has dried, use a 10" joint finishing knife to apply still another coat of joint compound. Feather this coat about 1-1/2" beyond the edge of the first coat.
  
  
• When the final coat is dry, sand it lightly to a smooth finish. Wipe off the dust with a clean rag to prepare the surface for the final coating of paint, paper, etc.
  
  
• The total width of the compound at each joint should be about 12" to 14".
  
  
• All nails should be dimpled just below the surface of the board as shown in Fig. 6. Conceal these dimpled areas by applying a first coat of joint compound with even pressure so the compound is level with the surface of the board. Press evenly, but not too hard–too much pressure on the knife might scoop the compound from the dimpled area.
  
  
• When the compound has thoroughly dried, apply a second coat. Let it dry thoroughly, then sand it lightly and apply a third coat.
  
  
• In areas where humidity is extremely high, apply a fourth coat of compound over the nail heads.
  
  
• The end or butt joints on wallboards are not tapered. Where these un-tapered butt joints come together, be sure not to build up too much compound. Compound built too high will create ridges in the wall, and may cause shadowing when the area is lighted.
  
  
• Feather the joint compound out on each side of the butt joints from 7" to 9". The final application of joint compound should create a joint approximately 14" to 18" wide where the butt joints come together.
  
  
• After attaching the metal corner strips as previously described, nail them securely into position, and use a 4" finish knife to spread compound mix 3" to 4" out from the nose of the bead.
  
  
• When the first layer is completely dry, sand it lightly and apply a second coat of compound mix, feathering the edges about 2" to 3" beyond the first coat.
  
  
• If a third coat is needed, feather it 2" to 3" beyond the preceding coat. This creates a tapered finish of joint compound approximately 7" to 9" wide at each metal corner.
  
  
• To finish off an inside corner with regular tape, apply joint compound with a 4" knife. Spread it evenly about 1-1/2" on each side of the angle.
  
  
• For both types of tape, cut the joint tape the exact length of the corner to be finished. Fold the tape lengthwise in the center and press it firmly into the corner.

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Ask for Other "Show-How" Instruction Sheets
Additional easy-to-use instruction sheets for home do-it-yourself projects are available from your local supplier of materials. Come in and ask for "Show-How" instructions when you get ready for that next handyman project!