Building a Half Wall

Knee Wall Construction

Introduction: A great way to divide a room space without closing it in is by building a half wall, also called a knee-wall. Building a half wall will provide you with additional wall space for placing furniture and some amount of privacy.

Half walls are easy to construct using standard carpenter tools, building material and hardware. Half walls are commonly built on the main house floor or in the basement. The instructions here are for building a basement half wall.

One of the difficulties in half wall construction is getting them stable. They must be firmly attached to an existing wall on one end, secured to the floor, and preferably a short right angle wall at the other end. In addition, I recommend that any half wall design be with 2 x 6s rather than 2 X 4s. The additional two inches will provide much more contact surface for attaching it to the wall and floor. The wider wall will also give you a lot more shelf width on top of the wall.

Instructions for Building a Half Wall:

Select the area where you want to build the wall. Insure there is a stud behind the wall board where you plan to attach the wall so the half wall will be tightly secured to the wall at the attach point. Check that the floor is level. If it is not you will have to use shims under the wall or adjust the height of the studs on the half-wall to compensate. Take notice of any obstacles such as pipes and outlets in the wall or the floor.
Cut the bottom and top plates to the desired length of the wall. Use a chalk line to snap a line on the floor to indicate the location of the bottom plate. The bottom plate should be pressure treated as it makes contact with the cement floor. Place the top and bottom plates side by side and face down on the floor. Draw a line across both plates every 16 inches as in standard wall framing. These lines represent the center of your studs. From each of those lines, measure over 3/4" (in the same direction) and draw another line. This line represents the edge of each stud. Draw some X's over the center lines to help show the placement of the studs.
Cut the studs to the desired length. The studs should be 3-3/4" shorter than the finished height of the wall to compensate for the upper and bottom plates and the finish cap.
Place the top and bottom plates on their edges on the floor with the lines facing inward. Position the studs between the plates and line them up with the corresponding lines on each plate. Nail the studs into the top and bottom plates. Two inch screws is an option.
Place the completed half-wall frame on the line you chalked on the floor. Make sure it is the pressure-treated bottom plate that makes contact with the concrete. Check to see that it’s set level on the floor. Use shims to make any adjustments.
Pre-drill holes through the bottom plate and into the concrete floor. Use Tapcon screws to fasten the bottom plate to the concrete, spacing the screws about 10 to 12 inches apart. It is also a good idea to use construction glue between the floor and the bottom plate to obtain more surface contact.
Secure the half-wall to the side wall using three inch screws placed approximately every ten inches.
If you elect to use a stub wall at the end of the half wall for more stability, attach it at a right angle to the half-wall and secure it to the floor.
At this point run any electrical wire for outlets or TV cable in the wall from the attached end.
The wall should be firmly secured to the wall and the floor at this point. Cut 1/2" drywall to size and cover both sides of the half-wall. Use a screw gun and 1-1/4" drywall screws to attach the drywall, screwing it into the studs. Make sure the top edge of the drywall is flush with the top of the top plate. Install corner bead on the end of the wall. Mud, tape and sand all joints.
Install a 1x6 clear pine cap on top of the wall. Using a hard wood is an option. Nail it in place using the 18-gauge finish nails. Stain or paint the cap as desired. Finish by priming and painting the drywall and adding some base molding.

That is all there is to it.

Related subjects:

Building a Floor On top Of Concrete

Building an In-Law Apartment

Framing a Finished Basement

Framing Walls | Wall Framing Layout

For more DIY information Check out these Resources

Building a Half Wall

Knee Wall Construction

Instructions for Building a Half Wall:

Cut the studs to the desired length. The studs should be 3-3/4" shorter than the finished height of the wall to compensate for the upper and bottom plates and the finish cap.

Place the top and bottom plates on their edges on the floor with the lines facing inward. Position the studs between the plates and line them up with the corresponding lines on each plate. Nail the studs into the top and bottom plates. Two inch screws is an option.

Place the completed half-wall frame on the line you chalked on the floor. Make sure it is the pressure-treated bottom plate that makes contact with the concrete. Check to see that it’s set level on the floor. Use shims to make any adjustments.

Pre-drill holes through the bottom plate and into the concrete floor. Use Tapcon screws to fasten the bottom plate to the concrete, spacing the screws about 10 to 12 inches apart. It is also a good idea to use construction glue between the floor and the bottom plate to obtain more surface contact.

Secure the half-wall to the side wall using three inch screws placed approximately every ten inches.

If you elect to use a stub wall at the end of the half wall for more stability, attach it at a right angle to the half-wall and secure it to the floor.

At this point run any electrical wire for outlets or TV cable in the wall from the attached end.

Install a 1x6 clear pine cap on top of the wall. Using a hard wood is an option. Nail it in place using the 18-gauge finish nails. Stain or paint the cap as desired. Finish by priming and painting the drywall and adding some base molding.