An installation wall made of plasterboards or on a metal grid, or on a wooden one, you can fix it by inserting a small piece of a new board. To do this, cut out the damaged fragment in the wall and insert a new one, properly trimmed. To screw it with screws, two wooden strips must be screwed inside the wall at the opening and only a new piece should be screwed to them.. The slats will form a support for a piece of board like this, so that it does not fall inside the wall, nor did she use the filler to putty.