Plaster is usually made from a mixture of gypsum, sand and water, and has great qualities for a wall finish: durability, structural rigidity, resistance to sound transmissions and high fire resistance. It can be readily applied to curved or irregularly shaped surfaces, and is usually applied in two or three coats to a backing called lath. The thickness of the plaster varies between ½ and ¾-inch, depending on the type of lath.
Plasterboard is a sheet material that consists of a gypsum mixture surfaced with a treated paper. The thickness of the plasterboard ranges from ¼ to ⅝ inch, depending on the application. The sheets are usually four-feet wide and are available in lengths up to 12 feet. When constructing walls using plasterboard, the material is fastened directly to the studs, and the joints are covered with tape. The edges of the plasterboard are recessed slightly so that when tape is applied, it is level with the surface. For this type of construction, the wood framing must be perfectly straight and true, otherwise the surface will be uneven and there will be visible joint lines.
In houses where the roof framing consists of trusses rather than rafters, a walls and ceilings inspection will likely reveal cracks at the wall-ceiling intersection in the interior rooms below the attic. Such cracks are generally caused by truss uplift, which causes the ceiling to move up and down in the course of a yearly weather cycle. The size of the cracks can vary from a hairline to an actual opening of an inch or more, but this is rather a cosmetic issue than a structural condition.
During a walls and ceilings inspection, look specifically for areas that need major cosmetic rehabilitation, such as broken walls or ceiling, loose and bulging sections of plaster, or disintegrating plaster. Sagging or bulging sections in a plaster ceiling pose safety risks because they may collapse. This problem is usually found in older homes, where the sagging condition is caused by broken plaster keys, which no longer lock the plaster layers to the supporting lath. The condition occurs over a period of time and is usually a result of vibration and wetting from roof and plumbing leaks, which weaken and crack the keys. If you find sagging sections of the ceiling during your walls and ceilings inspection, record this problem on your worksheet for future repair.
Major cosmetic damage is often the result of a water penetration trough inadequate or insufficient wall insulation. While performing a walls and ceilings inspection, look for water stains and if you find any, try to determine the source of the water. Not all stains indicate a current condition, so if you have a moisture meter check all water stains to determine whether or not the leakage condition causing the stain is active. If it is an active condition, record it on your worksheet for future repair.
A walls and ceilings inspection is necessary whenever you have ceiling water damage. Many homeowners avoid or postpone fixing their ceiling water damage, without realizing the tremendous effect it can have on other parts of the home. For instance, if a water leak caused damage next to a wall, the water may be running down the inside of the wall as well.
If you have any ceiling water repairs, all areas directly underneath it or next to it must be inspected, as they may have mildew, fungus or mold contamination. If you find any water leaks anywhere in your homes, make sure to have it fixed as soon as possible. Otherwise, just one small leak can end up costing a fortune in future home repair bills.