A knee wall is a construction term used for a low wall that separates interior or exterior areas. Knee walls are used for a variety of purposes. They can be used to provide delineation of rooms, create additional storage, separate gardens and courtyards or may be used in attics or garages to provide more living space. Knee walls by definition are short, about the height of the human knee, but may be built higher, as needed.

Knee Wall Construction

First, determine the height needed for the knee wall by measuring the area with a tape measure. Knee walls can be constructed with 2-by-4 pieces of lumber and drywall. Apply drywall on top of the frame and attach with screws, according to the Ron Hazelton home improvement website. Then set the knee wall into position and attach to surrounding walls. Next, apply drywall compound to cover the seams and smooth to an even surface. Prime and paint the wall as desired.

Exterior Knee Walls

Knee walls are constructed like other walls, but to a much lower height. Exterior knee walls may be used to define a courtyard area near the home. Other materials can be used on top of knee walls to extend the height, such as when low metal fencing is installed on top of a knee wall to form an enclosed area. Knee walls can also be used around fountains, water features or garden bed areas.

Interior Knee Walls

Interior knee walls can serve a number of purposes in interior areas. They are sometimes used in garages and attics to separate portions of the area that are heated from unheated areas. Attics, in particular, are often finished and used for living space. These knee walls form a separation between the floor and the eaves which slant down at the sides of the roof. The short wall creates a usable room within the attic, while eliminating spaces of the wrong shape or size.

Common Heights of Knee Walls

Most knee walls are constructed to reach a height of 36 to 42 inches. This generally fits areas such as under the eaves of roof lines. Knee walls can be shorter or longer than this standard height if needed to provide the necessary structure. Some knee walls, for instance in bathroom areas where they are used as a partition or to separate areas for privacy, may be up to 48 inches high. This type of knee wall may separate the toilet area from the rest of the room.

Insulating Knee Walls

Knee walls are often used to separate spaces that are heated from unheated areas. For instance, knee walls in attic areas that are used for additional living space are notoriously drafty. This type of knee wall should be adequately insulated to prevent heat loss and drafts. Insulating knee walls can be done by opening the wall and inserting fiberglass batting between the studs. The back of the knee wall can be covered with rigid insulation to prevent cold air flow.