How to Build a Little Half Wall

A large room can be made smaller by building a half wall.

A half-wall, also called a knee wall, can take an otherwise wide open space and divide it. This can effectively divide one room into two, while still leaving the feeling of open space because the wall is only a few feet tall and extends partway across the floor. Building a half wall is a project that a do-it-yourself homeowner with intermediate skills can complete.

Things You'll Need

• Stud finder
• Utility knife
• Pressure-treated 2-by-4 board
• Circular saw
• Safety goggles
• Drill
• Screws
• Untreated 2-by-4 boards
• Hammer
• Nails
• Level
• Assistant
• Drywall boards
• Straightedge
• Drywall screws
• Metal corner beads
• Staple gun
• Staples
• Joint compound
• Putty knife
• Drywall tape
• Medium-grit sandpaper
• Sanding block
• Fine-grit sandpaper
• Primer
• Paint brushes
• Paint roller
• Paint
• Ledge
• Stain
• Molding

Instructions

1. Mark the location of the half wall onto the floor and wall that it is extending out of. When choosing the exact location of the half wall, place it against a stud in the wall perpendicular to it. Use a stud finder to locate the stud.

2. Cut away the molding on the base of the wall where you are building the half wall. If the floor is carpeted, remove the carpet and carpet padding in that spot so you can attach the wall directly to the subfloor.

3. Cut a pressure-treated 2-by-4 board that measures the length of the half wall. This is called a sill plate, and is used to connect the frame of the half-wall to the floor.

4. Screw the sill plate to the floor every 6 inches.

5. Cut two 2-by-4 boards that match the length of the sill plate. Use regular lumber and get the straightest boards you can find. These boards are the top and bottom plates for the half wall.

6. Cut 2-by-4 boards to be the wall studs. Cut them long enough that, when combined with the thickness of the sill plate, top plate and bottom plate, the wall is at the desired height.

7. Nail a stud to each end of the bottom plate, then nail studs in between the end studs. Place the studs no farther than 16 inches apart and then nail the top plate to the tops of the studs.

8. Lift the frame on top of the sill plate. Check it for level (horizontally straight) and plumb (vertically straight). Nail the frame to the wall and the sill plate. You may want to have an assistant help you with this.

9. Measure and cut drywall boards to fit both sides and the end of the half wall. Hold a straightedge against the line where you want to make the cut and run a utility knife down the drywall. Snap the board where you cut into it.

10. Attach the drywall by screwing it to the studs with drywall screws. Use one screw every 8 inches. Cover the outer edges of the drywall by stapling metal corner beads to them.

11. Apply joint compound over the joints between the different sheets of drywall and the metal corner beads with a putty knife. Place drywall tape over the joint compound and run the putty knife over top to press the tape into the joint compound. Allow it to dry overnight.

12. Sand the joints with medium-grit sandpaper. Apply enough pressure to just remove the rough edges of the joints. Use a sanding block in the corner where the half wall meets the other wall.

13. Apply two more coats of joint compound and drywall tape to the joints, allowing each coat to dry overnight. Sand the second coat with the medium-grit sandpaper and the third coat with fine-grit sandpaper to smooth the surface.

14. Cover the half wall with primer. Use a paint brush to cut in along the edges of the wall and a paint roller to apply the primer to the main parts. Allow the primer to dry.

15. Paint the half-wall, using the same technique with which you applied the primer and allow it to dry. Apply a second coat of paint and allow that to dry.

16. Place a ledge or shelf on top of the half wall. You can purchase one at a home improvement store. Cut it to fit the length you need, then apply a coat of primer and paint, or stain the ledge. Nail it to the top of the half wall.

17. Nail molding to the bottom of the half wall.

Tips & Warnings

• Wear safety goggles when sawing the wood.

References

• Ron Hazelton's House Calls; How to Build a Room Divider; Ron Hazelton
• "This Old House": How to Frame a Partition Wall; Scott Gibson
• "The Family Handyman": Wall Framing Tips for New Construction