For every remodeling job that involves knocking down a wall, there's another that calls for putting one up. "If you're refinishing an attic or adding a closet or home office, you're going to need an extra wall or two," says This Old House general contractor Tom Silva.
Building a simple partition wall—a stud wall that divides an interior space without bearing any load—is a perfect introduction to the basics of home construction. This project employs the same principles and components that are used in the construction of any frame house: 2x lumber spaced and nailed correctly, then set plumb.
Think of it as Framing Carpentry 101. Even though all this work ends up buried behind drywall, shortcuts lead to trouble. Framing with good materials and smart techniques lay the groundwork for everything that follows: smooth walls, countertops that fit perfectly, and doors that swing without sticking.
How to Build a Partition Wall
1. Partition Wall Assembly Overview
2. Lay Out the Wooden Partition
- Mark the ceiling 3 inches from one wall where the partition will abut it. From that mark, drop a plumb bob and mark the floor. Repeat at the partition's other end.
- Measure the distance from each floor mark to its abutting wall. If it's not 3 inches, then that abutting wall is not plumb. Record the difference between the top and bottom measurements at each end for Step 3.
- Using the marks as a guide, snap a chalk line on the floor and the ceiling. Measure the chalk lines to determine the lengths of the sole and top plates. Cut the plates.
- If a doorway is planned, add 2 inches to the door's width and height to determine the dimensions of its rough opening.
- Cut two jack studs 1 1/2 inches shorter than the rough opening height. Cut two header pieces 3 inches longer than the opening's width.
3. Mark the Plates
- Lay the plates face-to-face. If the walls aren't plumb, stagger the plates by the differences in the Step 1 plumb-bob measurements. Mark stud locations 15 1/4 inches from plate end, then every 16 inches.
- Place header against sole plate in doorway; mark each end onto plate. Draw another line 1½ inches from the first. Draw an "X" between each pair of lines, showing king stud locations.
- Remove the header. Draw parallel lines 1 1/2 inches in from the header. Draw an "O" between each pair for jack studs. Transfer the lines to the top plate.
- At the first stud, draw a line across both plates. Work away from the end, drawing a line 1½ inches from the first. Repeat at each mark to indicate stud locations.
- Set header against top plate between king stud locations. Transfer lines from the top plate to the header, showing where the cripple studs go.
4. Measure the Studs
- To find the stud length, stack two 2x4 blocks face-to-face on the floor layout line and measure up to the ceiling layout line. These blocks represent the combined thickness of the sole and top plates.
- Take measurements at either end of the partition's location and at three spots in between.
5. Cut the Studs
- Count the number of king and common studs marked on the plate and cut them all to the shortest measurement using a portable circular saw and Speed Square.
- Also, cut all the cripples, including the two that lie against the king studs, to length: the length of the king stud minus the length of the jack, minus the thickness of the header.
6. Assemble the Pieces
- Lay all the pieces on edge and in position on the floor. Line up the ends of the studs with the marks on the sole and top plates. Line up the ends of the cripples with the top plate and header.
- Follow the assembly sequence shown in the illustration under Step 1. Start with the components of the door opening; finish with the common studs.
- Join pieces at right angles to each other first, by driving two 16d nails, side by side, through the face of one piece and into the end of the adjoining piece.
- For face-to-face connections (jack studs to kings, the header pieces) use 10d nails driven every 12-16 inches in a zigzag pattern.
Tip: For a nonload-bearing wall, jack studs may be pieced together from scraps of 2x4s until they completely fill the gap between the sole plate and the bottom of the header.
7. Tilt Up the Partition
- When all the pieces have been nailed together, tilt the wall into position so that the face edge of the top plate lands alongside the line on the ceiling. If necessary, get someone to help you raise the partition into position.
- If the fit is tight, use a sledgehammer and a scrap wood "pounding block" to tap the edge of the sole plate into alignment with the chalk line on the floor. If the partition runs perpendicular to ceiling joists, drive one 16d nail through the top plate into each joist.
- If the partition runs directly beneath a joist, nail into it through the top plate in every stud bay. If the top plate lands between the joists, nail it to blocking.
8. Check the Partition for Plumb
- Before driving in any nails, use a 4-foot level to check that the stud edges and faces are plumb (perfectly vertical). If adjustments are necessary, move the level and use a hammer to tap the partition into position. Then use the level to recheck for plumb.
- If you find any spots where the top plate isn't snug against the ceiling, slip thin wood shims under the sole plate at the appropriate stud locations to close the gap at the top.
9. Secure the Partition
- Fasten the sole plate (except at the door opening) by driving one 16d nail into each floor joist. If the wall sits in line with a joist, drive one 10d nail through the plate in each stud bay and into the subfloor. (On concrete slabs, drill through the sole plate and into the concrete, then drive in spring spikes, masonry screws, or masonry cut nails.)
- Nail the end studs with 16d nails every 12 to 16 inches into studs or blocking of the abutting wall.
- Once the wall is secured, cut the sole plate out of the door opening with a handsaw. Cut it flush with each jack stud, without sawing into the subfloor.
- To resist the force of slamming doors, toenail each end of the just-cut plate under the jack studs with two 10d nails.
10. Zigzag Blocking
In most cases, a partition wall built with 2x4s on 16-inch centers provides plenty of strength, but when Tom frames any wall more than 8 feet tall (or one that bears a load), he often adds blocking. These short pieces of lumber, nailed between the studs about halfway up the wall, "help keep the studs straight, and so add integrity to the wall and make it stiffer."
For this purpose, he prefers herringbone blocking, so called because of its distinctive zigzag pattern, which he routinely uncovers in older houses with studs that run a full two stories. (Blocking set edge up and flush with the stud edges serves another purpose: to provide a solid base for nailing wainscoting or anchoring pedestal sinks.)
Tom installs this blocking after the wall is raised into position. First he makes parallel 15-degree cuts in scraps of 2x4 so that the ends fit snugly against the two stud faces in each bay.
Then, with two 16d nails, he toenails through the face of each stud and into the blocking; the next piece he rotates 180 degrees relative to the first and toenails the block so one end lines up with the near end of the first piece. So it goes until all the bays are filled. Then the wall is ready for drywall.
"It's quick, cheap, and works great," he says of this. "What could be better than that?"