This Home and Garden video tutorial is going to show you how to repair damage around wall elements such as outlets. The video demonstrates how to repair a gap around a socket that was created due to a miscalculation on the part of the mason. The simplest way of repairing this would be to take the cover off, get a patch which is pre cut to the correct dimensions, peel it off, place it correctly over the opening in the wall and press it on. You could paint the area with matching color. Then put the cover back on and you're done!