If your walls have holes in them, you can easily repair drywall yourself using basic drywalling techniques:
For Small Dents & Damages
Scrape away loose pieces of wall with a paint scraper or other scraping tool, and then apply a lightweight spackle over the hole. Let it dry, and then sand down until smooth.
For Holes Caused by Doorknobs
Purchase a small patch kit from any local hardware store. Read the kit’s instructions, but all should be roughly the same. Stick the patch over the hole and use a drywall knife to cover the area with a lightweight joint compound. Do this in a crisscross pattern, feathering the edges so it blends together with the wall.
For Small to Medium-Sized Holes
An easy method for repairing holes that are 6” or less is called the “California Method.” To do this repair job, take a new piece of drywall, cut roughly 2” larger than the hole. Score the back an inch from each side, scoring off the loose gypsum but leave the paper backing intact. Hold it over the hole, using a pencil to trace around the gypsum onto the wall. Be sure to check for electrical wiring; they’re typically near wall studs. After you’ve marked the wall, cut out the traced area using a drywall saw, and then apply joint compound to the back of the paper backing. Next, press the piece into place, covering it with a layer or two of joint compound.
For Larger Holes
A hole is considered a large one if it’s over 6” in size. For this job, begin the same way you would for the smaller hole by cutting a new piece of drywall that’s larger than the hole. Then trace it over the space onto the wall using a pencil and remove the portion of traced wall using a drywall saw. Once again, be sure to check for wiring. Because you’ll be working with a larger area, you may be able to shine a flashlight in the newly cut wall to look for any potential hazards. Next, take two furring strips (narrow strips of wood or metal that are used to level a surface in order to finish a product) and hold them inside the hole on both sides, securing them into the wall with screws. Next, set the newly cut drywall patch in place and secure it to the furring strips using screws. Apply joint tape on each side, and cover with a layer or two of joint compound.
For Damaged Wall Corners
Use a hacksaw to cut the damaged corner bead (the material used in construction to make the corners look perfectly pointed), and then use a knife to cut the drywall around it. After you’ve removed the damaged piece of corner bead, cut a new piece to fit. Secure the piece using a classic hammer and nails, followed by applying joint compound.
For each of these projects, allow the spackle or joint compound to dry. Be sure to lightly sand each area, prime, and paint it for a good-as-new wall!