Walls and ceilings
The materials most often used for covering walls and ceilings are plaster and plasterboard. Plaster-usually made from a mixture of gypsum (a common mineral), sand, and water-has qualities that are very desirable for a wall finish: structural rigidity, durability, resistance to sound transmissions, and high fire resistance. In addition, it can readily be applied to curved or irregularly shaped surfaces. A plaster wall is usually applied in two or three coats to a backing called lath. Depending on the type of lath, the thickness of the plaster usually varies between 1⁄2 and 3⁄4 inch.
Plasterboard is a sheet material that basically consists of a gypsum mixture surfaced with a treated paper. Depending on the application, the thickness of the plasterboard can range from 1⁄4 to 5⁄8 inch. The sheets are usually 4 feet wide and are available in lengths up to 12 feet. When constructing walls using this material, the plasterboard is fastened directly to the studs, and the joints are covered with tape. The edges of the plasterboard are recessed slightly so that when the tape is applied, it is level with the surface. This type of construction requires that the wood framing be perfectly straight and true. Otherwise, the wall surface will be uneven, and there will be visible joint lines. If the moisture content of the wood used in construction is not very nearly that which will be attained in service, there might be nail pops and joint cracks. Popping nails is a condition most often found with plasterboard construction. It can be corrected easily. It often does, however, indicate low-quality installation.
In houses where the roof framing consists of trusses rather than rafters, you might see cracks at the wall-ceiling intersection in the interior rooms below the attic. The cracks are usually the result of 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. This condition is a cosmetic problem rather than structural. The easiest cosmetic repair is to cover the crack with decorative molding that is nailed to the ceiling and not to the wall. As long as the molding is wide enough, it will cover the crack as the ceiling moves up.
When you inspect a room, look specifically for areas that need major cosmetic rehabilitation, such as broken walls or ceiling, loose and bulging sections of plaster, and disintegrating plaster. Sagging or bulging sections in a plaster ceiling are a safety concern because of the possibility of collapse. This problem, if it exists, is usually found in older homes. Plaster is applied over a wood, metal, or gypsum lath. The sagging condition results from broken plaster keys, which no longer lock the plaster layers to the supporting lath. (See FIG. 10-1.) The condition occurs over a period of time and is usually caused by vibration and wetting from roof and plumbing leaks, which weaken and crack the keys. If there are sagging sections of the ceiling, record this problem on your worksheet for future repair.
Very often, major cosmetic damage is the result of a water condition. As you look at these areas, also look for water stains. Stains often show up as discolorations circled by a light brownish ring. If you see water stains, try to determine the source of the water. All stains do not indicate a current problem condition. You might be looking at the results of a problem that has been corrected. If you have a moisture meter, you should check all water stains to determine whether or not the leakage condition causing the stain is active. If it is, record it on your worksheet.
Water stains on a ceiling can be caused by several types of problems, such as water leaking between the tile joints around a shower or tub located in a bathroom above the ceiling, an ice dam on the roof, an open joint between a plumbing vent stack or chimney and the roof, leaky plumbing, or condensation on cold-water pipes located above the ceiling. Sometimes the cause is obvious, such as a faulty roof. However, you should be aware that leaks that originate in the roof can stain ceilings two or more levels below. The stains are not limited to ceilings just beneath the roof.
Sometimes the source of a stain cannot be explained by any of the above. On one inspection, I noticed that the ceiling of one room had several stains that were still damp. I knew that there were no plumbing pipes above the ceiling and that the roof was in good shape.
Frankly, I couldn’t figure out why the ceiling was damp. All of a sudden, I noticed that water was dripping from one section of the ceiling. I then went upstairs to the room above and found what was causing the leak. Apparently, the owner kept a puppy that was not housebroken in the room. Whenever the puppy missed the newspapers that were placed there for training purposes, the urine seeped through the floor joints, wetting the ceiling below.
Ceilings can also be covered with composition tiles. These tiles are generally made from asbestos, glass fiber, or fiberboard. They can be applied directly over plaster or plasterboard ceilings or over furring strips and are usually interconnected with tongueand-groove joints. If you are inspecting an older home with plaster walls and ceilings and find yourself in a room that has a tile ceiling, the tiles were probably installed to cover broken and cracked sections in the original ceiling. It is becoming increasingly difficult to find a good plasterer. Consequently, when renovating an older home, many people cover a ceiling with tiles or plasterboard rather than have it replastered. Look specifically for loose and sagging sections. These sections must be resecured; otherwise, they can cause adjacent tiles to loosen, which can eventually result in a “domino” effect, causing most of the tiles to come down. (See FIG. 10-2.) I inspected a house the day after two-thirds of the ceiling tiles in one room came thundering down. The owner told me that there always had been a few loose tiles.
Water stains on walls facing the exterior might be an indication of water seepage through open joints in the exterior siding. In particular, this condition has been found in older homes with an exterior brick or stone siding and is usually caused by wind-driven rain penetrating cracked and deteriorating mortar joints. When water stains and peeling and flaking paint are found on walls just below windows, it is usually an indication of leakage through open exterior joints around the window.
Fig. 10-1. Ceiling plaster can sag down from lath when keys securing base coat give way.
Cracks in walls are normally merely of cosmetic concern. However, when walls are cracked and the windows and door frames in that room are not level, the condition might be indicative of a structural problem and should be evaluated by a professional.
When the walls are covered with wood or hardboard panels, cracks will not be visible. In quality homes, panels are normally installed over a plasterboard wall. This type of backing provides added rigidity and, when applied on exterior walls, added insulation. If the room you are inspecting has a panel wall, push on the panel at a point between the studs (the studs are usually located 16 inches apart, in some houses 24 inches apart). If the wall panel yields under your push, there is no plasterboard backing. I inspected a new house just after construction and prior to occupancy. The buyer specifically asked me to check the plasterboard because he was paying extra for 5⁄8inch rather than 1⁄2-inch plasterboard. The builder did install the thicker plasterboard, but in those rooms that were paneled, the builder completely omitted the plasterboard behind the panels because it was not visible to the buyer.
The trim around the various joints in the room should be inspected and checked for missing, loose, cracked, and broken sections. Although a minor element, trim in this condition is an indication of shoddy workmanship in new construction and neglect in a resale.