Spacing Between Wall Cavities

Finding Studs

• You can locate wall studs with a stud finder or by tapping on the wall. Listen for a solid sound, which indicates a stud is beneath. Alternately, you can pass a strong magnet over the baseboard to find the finish nails, which indicate a stud is directly beneath. Once you locate one stud, you will locate the next stud 16 or 24 inches from the first one. Knowing how far apart the studs are helps you determine the cavity space.

Wall Cavity Width

• Standard spacing of wall studs is 16 inches on center. That means that from the exact center of one stud to the exact center of the next stud, it will be 16 inches. Typical 2-by-4 inch studs are actually 1 1/2 inches by 3 1/2 inches. When installed on 16-inch centers, the cavity space between the studs measures 14 1/2 inches from stud to stud. In some houses, builders install studs on 24-inch centers. This results in a 22 1/2 inch cavity width.

Wall Cavity Depth

• If you’re going to recess a cabinet or shelf into a stud space, it’s also important to know the depth of the cavity. If the builder uses standard 2-by-4 studs, which are 3 1/2 inches wide and the drywall is a half inch thick, the cavity depth is 4 inches from the surface of the drywall to the back of the drywall on the other side of the wall. While most walls contain 2-by-4 studs, some walls contain 2-by-6 studs. The cavity depth in these walls is 6 inches.

Framing Considerations

• The cavity space nearest a door or the end of a wall is likely to be narrower than the spaces between studs in the middle of the wall. Doorway framing may feature double studs and there is no hard, fast rule that tells the builder where to position a doorway. Walls that bear heavier-than-normal loads may also have smaller stud spaces, if the builder installed the studs on 10-inch centers to give the wall added strength. If you have an off-size wall, the best way to determine the cavity spaces it to locate the studs and subtract 1 1/2 inches from the distance from stud center to stud center.