Because of the nature of the room, the bathroom must be well ventilated. Ventilation can be provided naturally through an openable window or mechanically by an exhaust fan. If there is an exhaust fan, try to determine where it discharges. The air drawn through the fan should discharge into the atmosphere. This can be accomplished through the use of a duct that terminates on the side of the building or one that extends up through the attic and terminates on the roof. When the bathroom is located on the level just beneath the attic, the exhaust fan very often discharges directly into the attic. This is undesirable because the moisture-laden air can cause condensation problems in the attic. From a convenience point of view, many builders often connect the exhaust fan to the lighting circuit so that both are controlled by one switch. This is not an energy-efficient installation, since the exhaust fan is not always needed. If you see such a setup, you might want to consider rewiring the fan so that it can be controlled by a separate switch.
A recurring problem in bathrooms is water leakage through cracked and open tile joints around the tub or shower. This condition requires periodic maintenance and if neglected can cause considerable cosmetic damage. Check the tiles for cracked and open joints. Lean over the tub or go into the shower and press on the tiles, particularly at the lower portion of the walls. Loose tiles will move slightly or might even come out. If the tiles yield, it is usually an indication that the plaster or plasterboard backing has suffered some deterioration from water seepage. Depending on the severity of the deterioration, it might be necessary to rehabilitate that portion of the wall. Sometimes the cracks are not readily visible but will nevertheless allow water to seep through and wet the wall behind the tiles. You can check for leakage by using your moisture meter on the tile wall.
If the walls around the tub and shower are not kept watertight, water can leak around open areas, wet the ceiling below, and eventually rot the wood framing and cause the ceiling to deteriorate. Missing tiles must be replaced; loose tiles must be resecured; and cracked and open joints must be regrouted or caulked. Caulking is the procedure most often used for making repairs. A tube of caulking compound is available at any hardware store.
If the walls around the tub or shower have a panel finish rather than tile, check the joints for cracked or open sections. Sometimes the tub or shower and its associated walls are an integral unit made of molded plastic. In this case, leaks through open joints are not a problem. Many homes have showers and tubs with doors to prevent water from splashing onto the floor. The doors must be made with safety glass or plastic and should be checked for cracked panes and ease of operation.
When the shower base is covered with ceramic tiles rather than molded plastic or is terrazzo-constructed, there is the potential for a problem because of a faulty shower pan. A large lead or plastic sheet is normally installed below the tiles at the base of the shower to collect water that seeps through cracked and open tile joints. If the shower pan is intact, it will direct the water down the drain without incident. However, as the shower pan ages, the joints very often deteriorate, resulting in water leakage through those joints. If you notice large water stains on or damage to the ceiling of an area below the shower, you should suspect a shower-pan problem.
If you have the seller’s permission, you can test for a faulty shower pan by covering the shower drain and filling the shower base with about an inch of water. Let the water stand in the base for about forty-five minutes. If the shower pan is faulty and there are cracks in the base tile joints, water will seep through and wet the ceiling below. When the tile joints at the base of the shower are all sealed, even if the lead pan is faulty, there will be no leakage. Instead of replacing a faulty shower pan, many homeowners simply recaulk the tile joints at the base of the shower. This is considered a makeshift fix. If you find a heavy layer of caulking in the shower base, even if you do not find water stains on the ceiling below (the ceiling could have been repainted after the makeshift fix), you should suspect shower-pan problems.