Yes, you can install drywall over plaster, but there are important factors to consider. While it can create a smooth, flat surface, it is often not the best approach. Installing drywall over plaster will increase the wall's thickness, which can cause issues with existing window and door frames that may no longer fit. You might also need to adjust power outlets to keep them accessible. A better, though more expensive, option is to remove the old plaster and lath entirely before installing new drywall. Drywalling directly over plaster seals in the old material, and if any problems arise later, you will need to remove both layers down to the structural beams for repairs. Given the potential complications, this job is best handled by professionals.

A common cause of separation between a wall and the ceiling is truss lift—this can happen to the ceiling of rooms directly under the attic when the seasons change and wood building materials dry out, shrink, and shift. Roof trusses often dry out at different speeds, and if the bottom pieces dry out faster than the top pieces, they can shrink and pull the attached drywall away from ceilings and walls, causing cracks. Fortunately, truss lift is only a cosmetic problem, not a structural problem, and you can fix it by separating the ceiling drywall from the roof trusses, and patching the cracks.

To properly clean and maintain your skip trowel drywall texture, dust the surface weekly with an electrostatic duster or vacuum with a soft brush attachment. Never scrub the surface. You can remove stains by gently applying a mild detergent solution with a paint roller, removing it with a damp roller, and drying with a dry roller. To cut down on cleaning frequency, avoid indoor smoking and limit the use of fireplaces.

You can usually tell if you have plaster or drywall by touch (plaster is harder, colder, and smoother than drywall) or by tapping on it (drywall sounds hollow, plaster does not). If you still cannot tell, peek under an outlet cover and check the cut edges. The rough edges show the composition of the wall. You will see either drywall (two paper sheets sandwiching gypsum material) or only plaster material (no paper sheets).