How to Build an Interior Wall
Walls are obviously a major building block of our home's indoor architecture. Interior walls keep us private, sequester heating and cooling, dampen sounds, and define spaces. Interior walls can transform one big room into two smaller rooms or they can make a closet out of nothing more than empty space.
Basics of Interior Walls
Walls are either load-bearing or non-load-bearing. Load-bearing walls carry their own weight plus the weight of materials above them such as header beams, flooring, furniture, roofs, and more. Non-load-bearing walls carry only their own weight and are not structurally integral to the home.
Interior walls are sometimes non-load-bearing. Often, interior walls that divide rooms or create small spaces such as closets, pantries, and powder rooms are non-load-bearing.
Interior Wall System Structure
Interior non-load-bearing walls consist of:
- Bottom Plate: Horizontal bottom plate made of a two-by-four, resting on and connected to the floor
- Top Plate: Horizontal top plate, also a two-by-four, that connects to the tops of the vertical studs and to the ceiling
- Studs: Vertical two-by-four studs spaced every 16 inches, on-center
- Drywall: Drywall fastened to the front and back of the wall system
How You Will Build an Interior Wall
In new-construction houses and additions, complete interior walls are built on the floor, then they are tilted up and fastened into place. With existing construction, though, it is difficult to tilt a pre-built wall into place. In order to complete the tilt, the wall would need to be shorter than the space it is required to fill.
Instead, you will attach the bottom plate to a solid place on the floor. Next, you will attach the top plate to the ceiling, directly above the bottom plate. Studs will be measured individually, then they will be toe-nailed into place.
To complete the wall, drywall will be hung on the studs. The screws and seams will be filled with drywall compound.
Codes and Regulations
Even with a non-load-bearing wall, many municipalities require you to apply for a building permit before executing the project. The interior wall needs to be built up to code, with studs spaced every 16 inches on-center. Check with codes in your area to tailor the wall to community requirements.
What You'll Need
Equipment / Tools
- Speed Square
- Circular saw
- Cordless drill
- Six-foot step ladder
- Laser level
- Electric miter saw
- Framing hammer
- Tape measure
- Carpenter's pencil
- Drywall knife
- Painting supplies: roller frame, cover, and tray
- 9 Two-by-fours, each 8-foot long
- 2 Drywall sheets, 8-foot by 4-foot
- Galvanized nails, 2 1/2-inch long
- Drywall screws, 1 5/8-inch long
- Drywall joint compound
- Paper drywall tape
- Pressure-treated two-by-four (optional for concrete floors)
- Drywall primer
- Interior paint
Locate a Position For the Bottom Plate
The bottom 8-foot-long two-by-four must be fastened to a solid spot on the floor. If the floor is concrete, the concrete is considered solid enough for a bottom plate. If the floor is wood (wood joists below a floor covering), the wall should be placed either directly on a parallel joist or perpendicular (90 degrees) to the floor joists. You can do this by measuring the joist locations in your basement or crawl space and then transferring the measurements to the floor inside.
Mark the Top and Bottom Plates
Put the top and bottom plates next to each other on the floor. Use a short scrap piece of two-by-four to mark a stud position at each end. Next, mark five positions between those two outside marks. These five marks should be 16 inches apart, on-center. Use the Speed Square to transfer the marks from one plate to the other plate.
Fasten the Bottom Plate
For a concrete floor, fasten the bottom plate, which should be a pressure-treated two-by-four, to the floor with concrete nails using a powder-actuated nail gun.
For wood floor systems, attach the bottom plate to the floor with a hammer and nails. Drive the nails by hand directly through the two-by-four, then the floor covering, and into the joist. The lumber for this application does not need to be pressure treated.
Fasten the Top Plate
The top plate must be directly above the bottom plate. It must be connected across perpendicular ceiling joists or directly on one joist. Use the laser level plumb function to ensure that the top plate is directly above the bottom plate. Nail it into place.
Measure and Cut the Studs
Move the electric miter saw nearby. Begin with one stud at the end. Measure from the top of the floor plate to the bottom of the ceiling plate. Transfer this measurement to a stud, then cut this stud with the saw. Continue in this fashion down the rest of the wall.
Nail the Studs in Place
With the hammer, toenail each stud into its corresponding position. Toenailing is a process in which screws or nails are driven sideways into the upright stud through to the bottom or top plate. Begin by driving the nail in straight until it grabs the stud, then angle it upwards to about 60 degrees and drive it all the way in.
Hang the Drywall
Hang the drywall horizontally on the studs, one above the other. Fasten the sheets to the studs with the cordless drill and drywall screws. By most building codes, the screws should penetrate at least 5/8-inch into the wood.
Fill the Screw Holes
Use the drywall knife to fill the screw holes with joint compound.
Fill the Drywall Seams
With this wall, there will be two 8-foot-long drywall seams. Finish the drywall by embedding the paper joint tape in the joint compound laid along the seam. Cover with more joint compound. Do not exceed the space of the seam.
Let the compound dry, then check for any gaps and fill if necessary. Sand any parts that aren't completely smooth after all the compound is dry (follow manufacturer's guidelines).
Paint the Wall
Roll primer onto the drywall. Let it dry, then paint the wall the color of your choice.