Learning how to repair drywall is fairly straight-forward and most of the steps can be used for various size holes. The most important item to remember in drywall repair is that it's always better to apply 3-4 coats of drywall compound with sanding between coats rather than lumping on a thick coat.
I've split the drywall repair steps into a couple of categories, namely small holes and larger holes as they do require different materials and steps in order to achieve a professional job.
Let's start off with some of the tools and products necessary for you to repair drywall holes and cracks...
General Tools Needed
Putty Knives - various sizes of 1 inch to 6 inches
Spackling
Drywall/Joint Compound
Sandpaper or Sanding Sponge
Straight-edge or Ruler
Pencil
Drywall Saw
Utility Knife
Tape Measure
Drywall Screws
FibaTape Drywall Tape
FibaTape Wall Bandage
FibaTape Crackstop
Repairing Small Holes (< 3/8")
How to repair drywall holes that are about 3/8 inch or smaller, there's no need for any wall bandage or drywall tape in these cases.
Steps:
Examine the hole closely and if there are any protrusion, take the end of your putty knife or even screwdriver, and press the protrusion flat.
Ideally, you want to create a small dimple or indentation into the drywall so that the drywall compound can be applied and sanded to leave a level and smooth surface.
Apply a thin coat of drywall compound or spackling with a putty knife.
Let dry completely then sand smooth - try to blend the outer edges smoother to the wall surface. Learning how to repair drywall properly comes with some patience and practice.
If needed, apply a second coat, dry and sand.
Repairing Large Holes (3/8" - 5")
How to repair drywall holes that are larger than 3/8 inches up to 5 inches will require the FibaTape Wall Bandage or Patches. You can buy them in a couple of sizes - the largest one is a 7"x7" square mesh that can cover holes no larger than 5 inches. The wall bandages/patches also come with a thin metal backing for extra support for the larger holes and I highly recommend using this type.
Steps:
We'll be using the "wall bandage" or patch for this job. Simply measure the damaged area and cut the square patch 2 inches larger.
The backing of the patch is adhesive so you can easily stick it over the hole so that 1 inch of the patch extends on all sides.
Apply the first coat of drywall compound over the mesh and smooth it out with a putty knife. Don't worry about seeing some of the mesh through the compound on this go, since we'll be applying 1 or 2 more coats later.
Once dry, lightly sand the area and wipe the dust away.
Apply a second coat of compound, this time feathering it out an inch or two further into the surrounding wall.
Again sand smooth and remove dust from the area once dry. Access the patch and see if you need one more coat or not. Some larger holes might.
Repairing Larger Holes (> 5")
How to repair drywall holes that are larger than 5 inches will require the task of cutting out the damaged drywall area and replacing it with a new piece of drywall.
Steps:
First, check inside the hole for any wiring since you'll need to cutting the damaged section out
Using a tape measure, measure the damage area and mark out on a new piece of drywall for replacement.
Cut this new replacement piece and place over the damaged area, then trace around it with a pencil.
Using a drywall saw or utility knife, cut this area out following your square markings as best as you can.
We'll also need to use a couple of pieces of 1x2" wood strapping to be used as a backer and place where we can attach the replacement drywall piece into the square hole. Cut the piece of wood 4 inches longer than the height of your square hole.
Insert the first wood piece through the hole and hold it against the back of the wallboard on the left side so that 2 inches are free above and below the square hole.
Drive a drywall screw through the wall into the piece of wood - one at the top and one at the bottom to hold the wood piece in place.
Do the same for the second piece of wood strapping on the right side of the hole. Now you're ready to attach the replacement drywall.
Place the new drywall piece into the square hole against the wood pieces you just installed.
Using drywall screws, attach the replacement drywall to the wood backings.
Apply drywall tape mesh around the square seams - try not to overlap as this will just be extra height or thickness to cover.
Put the first coat of drywall compound over the entire area and let dry.
Sand and remove the dust. Apply a second coat and extending an extra inch or two on all sides to feather it out more.
If you need a third coat, apply, dry and sand as well.
Here's one of the best videos that I've seen that covers how to repair drywall holes of various sizes:
