No matter how strong the drywall panel, chances are it eventually will need repair - whether from door-knob dings or furniture being moved, or from water damage or renovations. A drywall contractor will be able to tell whether your wall is drywall, plaster or a combination of the two. (Homes built before 1960 are more likely to have plaster over wood slats. Plaster walls have a hard white coat and crumble easily underneath. Drywall is softer. Different techniques and different materials can be used depending on the wall's composition in Maryland.

The goal for repairing holes is to remove as much of the damaged area and dust as possible, and fill in the gaps with joint compound or plaster. The deeper the gap or hole, the more layers are needed to pack deep inside it. Building layers makes for more solid repairs. Tape and a final compound layer, combined with sanding for a smooth finish (or blending into the wall's existing texture), will leave the wall ready for paint or wallpaper.

A drywall specialist will use similar techniques for other problems - cracks, exposed screws or nails, water damage, filling in electrical box openings, etc. But there are nuances that make each repair different.