The windows should be checked during the exterior and the interior inspections. The overall condition of the windows should be checked during the exterior inspection; the operation of the windows should be checked during the interior inspection. (See the section on windows in chapter 10.)

Many types of windows are used in residential structures. The most common types, as shown in FIG. 5-6, are double-hung, horizontal sliding, casement, awning, jalousie, and fixed-pane.

The double-hung window is the most common window unit in older and newer homes. It consists of upper and lower sashes that slide vertically past each other. The sashes are held in a fixed position within the window frame by a friction fit, counterweights, or spring balances. In some windows, the sashes are removable for ease of maintenance such as cleaning or painting. One variation of the double-hung window is the single-hung window; the upper sash is fixed, and the lower sash is movable.

Real Estate Home Inspection photographs of house defects

Real Estate Home Inspection photographs of house defects Real Estate Home Inspection photographs of house defects

Fig. 5-6. Window types: A-doublehung, B-horizontal sliding, C- casement, D-awning/fixed-pane combination, E-fixed-pane.

The sashes in a horizontal sliding window slide horizontally on separate tracks. The most common design consists of two sashes, both of which are movable. However, sometimes one sash is fixed. In most of these windows, the sash can be removed for cleaning.

Casement windows consist of two or more sashes hinged at the side and mounted so that they swing outward. The sashes are opened and closed by a cranking mechanism, a push bar mounted on the frame, or a handle fastened to the sash. Because the sash opens outward, a storm sash or screen must be attached to the inside of the window.

Awning windows have one or more sashes hinged at the top and mounted so that they swing out at the bottom. They are opened by push bars or cranking mechanisms similar to those on casement windows. As with casement windows, screens and storm sashes are mounted on the inside.

Jalousie windows are basically adjustable louvers. The louvers are glass slats (several inches wide) held by an aluminum frame at each end. The frames are interconnected by levers so that the slats open and close in unison, like venetian blinds. Jalousie windows are crank-operated and provide good ventilation. However, because of the many glass slats, they are troublesome to wash and are not weathertight. Even with a storm sash, cold-air leakage occurs around the windows. In northern climates, jalousies are usually limited to use on porches and breezeways.

Unlike the preceding windows, which are movable and provide ventilation, fixed-pane windows are stationary and are used only to provide daylight and outdoor views. They can be used alone or in combination with sliding, double-hung, or swinging windows to achieve a custom design.

With the exception of the jalousie windows, available only in aluminum, all of the windows are available in wood, metal (steel or aluminum), and vinyl-clad frames. If you are not sure whether the metal window frames are steel or aluminum, you can always tell the difference by using a magnet. A magnet sticks to a steel frame but not to an aluminum one.

Metal frames get quite cold during the winter months. Consequently, some of the water vapor in the air inside the house tends to condense on the frames. To reduce this condensation, several manufacturers produce metal-framed windows with a thermal barrier that prevents the outside frame from touching the inside frame. This substantially reduces the condensation but does not eliminate it. Since wood has a greater thermal resistance than metal, wood window frames normally do not get cold enough for condensation to form on their inside surface.

Although wood windows provide a better insulation than metal windows, they do have a tendency to swell or shrink with changes in moisture. A wood sash that absorbs moisture will expand and bind in the frame, so that it does not operate freely. Wood windows should be treated (by the manufacturer) with a water-repellent preservative to resist decay and moisture absorption. In the past, not all windows were so treated; thus rotting sections and binding sashes are occasionally found.

The glass used in windows must be of sufficiently high quality to minimize distortion. Years ago, because of the difficulty of manufacturing large distortion-free panes, window glass was available only in small sheets. Consequently, to fill a large opening such as a window sash, small panes of glass were used and held in position by framing strips called muntins. Today, even though large windowpanes are available, muntins are still used to create a special architectural effect. Some window manufacturers provide preassembled wood or plastic dividers that simulate muntins. The dividers merely overlay the large windowpane and snap in and out of the sash.

Windowpanes are also available with single and double glazing. A double-glazed window, a thermal (or insulated) pane, reduces heat loss or gain through an equivalently sized single-pane window by about 50 percent. It also reduces condensation on the inside surface. With some windows, triple glazing is also available.


When inspecting windows, look for cracked, broken, and missing panes. Check the joints between the sash and the window frames to see whether they are filled with paint. If they are, the windows might not open, and minor maintenance will be needed. The condition of the joints between the glass pane and the sash should be inspected. Are any panes loose? Most windowpanes are secured to the sash by bedding and sealing with a glazing compound such as putty. If putty is used, are any sections cracked, loose, chipped, or missing? Some panes are secured to the sash by wood strips (trim). Check the strips for cracked, loose, and missing sections. Note any of the above items on your worksheet for later correction.

Look at the overall condition of the window frames and sash. Windows exposed to the elements are vulnerable to weathering deterioration. Are any wood sections cracked and rotted? Steel windows can rust. Depending on the extent of the deterioration, some windows require simple repair; others, replacement. All the windows generally are not visible or accessible during your exterior inspection, especially the windows on upper levels. The exteriors of those windows, and their operation, should be checked during your interior inspection.

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