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How to Patch and Repair Drywall

Here are tips and suggestions on how to patch and repair plasterboard walls. Read these suggestions carefully to help you make such repairs easily and quickly.

REPAIRING SMALL DENTS IN WALLBOARD

  • Objects that come in contact with wall board can cause dents or scratches in the surface. These indentations are easy to repair.
  • First, sand the surface thoroughly (see image). This sanding roughens the surface and provides a good base for the joint compound you will use.
  • Use coarse sandpaper and a good sandpaper block. For large areas to be repaired, use a power sander.
  • Fill the dent with a good grade of joint compound using a 3" or 4" spreader (see image). Spread the compound evenly, pressing it firmly into the dented area.
  • For extremely large dents, allow the compound to dry overnight and then apply a second coat.
  • When the material is completely dry, sand the area and prime it for a coat of paint or other finish.
  • Be sure to remove any high or low spots in the patched area with a fine sandpaper.
  

PATCHING CRACKS IN WALLBOARD

  • Various types of patching materials are available for patching drywall. These include adhesive and non-adhesive drywall tapes, fast-drying patching compounds and drywall bandages.
  • Regardless of the type of patching materials you use, read the manufacturer's instructions carefully and follow each step as suggested. Some patching compounds dry quickly, while others require longer periods to dry.
  • Be sure the cracked area to be patched is completely clean and dry. Remove all dirt from the area and clean out all cracks.
  • Apply the patching plaster with a wide and flexible putty knife (see image above). Apply the compound by working across the crack with strokes in both directions. This method is the best way to work the patching plaster into the crack.
  • Force the patching material into the crack with strong, firm strokes (see image). Examine the crack after each stroke to ensure that enough material is applied at all points.
  • Use the putty knife as a scraper to remove any surplus material (see first image below). Move it along the cracked area gently to scrape away the surplus material that was applied by the double strokes.
  • You may want to dip the putty knife into water and make a final pass along the repaired area (see second image below). Touch up any areas that need more patching material.
  • After the patched area has dried completely, sand and prime it to prepare for the finish you desire.
  

PATCHING SMALL HOLES IN WALLBOARD

  • You can repair small holes, up to 4" to 6", in drywall using drywall bandages. To make a drywall bandage, use a keyhole saw to make the hole into a square or a rectangle (see image). Cut a piece of drywall the same shape as the hole. It should be 2" longer and 2" wider than the hole.
  • Lay the piece of drywall down on a flat surface, shiny side down. Measure 1" from all four edges and draw a line. This should form a shape the side of the hole.
  • Using a straight edge and a utility knife, cut through the drywall to the bottom layer. Do not cut the bottom layer of paper. Using a putty knife, remove the top layer of paper and core all the way down to the bottom layer of paper (see first image below). Be careful not to tear the bottom layer.
  • The cut part of the patch should fit into the hole. The paper edge should cover about 1" around the hole. Apply a thin layer of patching compound around the hole. Place the patch into the hole (see second image below). Using a putty knife, work the paper edge down into the compound. Feather the edges of the compound and allow it to dry. You may need to sand lightly and apply a second layer of compound to finish the repair.
  

PATCHING LARGE HOLES IN WALLBOARD

  • Larger holes, up to 12", require a slightly different repair which provides more support. Again use a keyhole saw to form the hole into a square or a rectangle.
  • Cut a patching piece of wallboard that's about 2" larger than the hole to be repaired (see image). Punch or drill two small holes through this piece of board and tie a stick to it, as illustrated. Allow for about 8" between the board and the stick.
  • Apply a smooth coat of good grade adhesive all around the edges of the piece of patching material.
  • Insert the patching board through the hole and position it so the adhesive fits firmly against the solid area around the hole.
  • Now turn the stick clockwise twisting the string and increasing pressure against the patch board at the rear of the hole (see image). When the string has been thoroughly tightened, it will hold the board firmly into place until the adhesive dries.
  
  
  
  • Give the adhesive time to dry. Then fill in the area with a good grade of patching plaster (see image). Leave the stick and the string in position during the patching process.
  • You may need to apply two or three layers of patching plaster to build up the patched area. Always allow one layer to dry before applying another.
  • Remove the stick and string just before the material dries. Smooth out the area then let the patch dry thoroughly.
  
  
  • When the area is completely dry, sand off all high spots and apply a prime coat for paint or other finish (see image).
  • Use a fine grade of sandpaper and a sanding block for the finish sanding work.
  • Larger holes in wallboard require some type of supporting brace for the patch.
  
  
  • Use a short piece of 2x4 cut to the proper length as a supporting brace for patching a large hole in plasterboard (see image).
  • Cut two pieces of 2x4 to a length about 8" longer than the distance across the hole.
  • Apply a good grade of cement to one piece of 2x4, then insert it through the hole. Tie it to another piece of 2x4 holding it parallel in front of the wallboard.
  
  
  • Allow the pieces of 2x4 to remain tied in this position until the cement dries. Most cements require about one hour to dry.
  • Next, remove the supporting piece of 2x4 in front of the wallboard by untying the string (see image). The cement will hold the back piece of 2x4 firmly in position, providing a support brace for the wall patch.
  • Now cut a patch block to the exact dimensions of the sawed-out area (see first image below). The block will be slightly smaller than the hole itself, but cut it to fit as tightly as possible.
  • Apply cement to the back of the patch block and the support brace, then put the patch into position in the hole.
  • Use a firm putty knife or patching spatula to apply joint compound all around the patch board (see second image below).
  • Work the patch compound thoroughly into all cracks. Scrape away any surplus material, then allow the patched area to dry completely.
  • When the area has completely dried, use a regular sanding block and a piece of fine sandpaper to sand away any high areas on the patched surface (see third image below).
  • A prime coat can now be applied to prepare the wall for painting.
  
TOOL AND MATERIAL CHECKLIST
Sandpaper (Coarse and Fine)Joint Compound
Keyhole SawGood Grade of Adhesive
Wallboard Tape (Regular or Adhesive Backed)Pieces of Wallboard
HammerSandpaper Block
ScraperPutty Knife
Hand SawHeavy Cord
Short Sections of 2x4Small Nails
Drywall BandageUtility Knife
PrimerCement
StickString

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Check your state and local codes before starting any project. Follow all safety precautions. Information in this document has been furnished by the North American Retail Hardware Association (NRHA) and associated contributors. Every effort has been made to ensure accuracy and safety. Neither NRHA, any contributor nor the retailer can be held responsible for damages or injuries resulting from the use of the information in this document.

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