Plasterboard, also know as drywall, is a piece of plaster pressed tight between two pieces of paper. It is used as a cheap construction material in many modern homes. Because it is thin, it is often brittle. Moisture on the wall or a hard slam from a door can cause cracks in the material. It is possible to patch plasterboard holes and cracks with cheap materials. If cracks are running both vertically and horizontally along the wall, have your foundation inspected.
Peel loose paper away from the wall.
Cut out the damaged area with a keyhole saw so it is a square shape. Cut two wood strips and insert them into the wall. Secure them to the drywall with drywall screws and a drill. Cut a new piece of drywall and insert it into the hole. Secure it to the wood strips with drywall screws. Cover the drywall with drywall mesh.
Scoop a large chunk of drywall compound onto your long, flat putty knife. Scrape the putty think over the hole. Let the putty dry for a few minutes. Scrape one further pass along the hole to spread the patch thin. Apply a second coat once the first dries.
Apply a third coat of drywall compound over the hole with a 6-inch putty knife.
Apply a fourth and final coat over the hole with an 8-inch putty knife. Feather the edges of the top coat thin so it blends in with the rest of the wall.
Sand the wall to make the patch smooth.