Wall Framing

Walls carry the roof and upper floors down to the foundation, and they set the shape of every room. A framing crew builds them flat on the deck, then stands them up. The work is fast once you know the parts and the sequence. Mistakes are also fast, and a wall that falls during raising can break bones or worse.

This guide covers stud walls in platform framing. Numbers are from common practice and the International Residential Code (IRC). Follow your plans and local code, especially for shear walls, high-wind and seismic details.

What You Will Be Able to Do

• Name every part of a framed wall and what it does.
• Figure a rough opening and a header stack-up.
• Follow the wall-building sequence from cut list to nailed off.
• Build corners and intersections that allow insulation and drywall backing.
• Stand, brace, plumb and line a wall safely.

Parts of a Wall

Wall Height and Stud Length

The most common wall has a single bottom plate, two top plates and studs precut to 92-5/8 inches.

• 92-5/8 + 1-1/2 + 1-1/2 + 1-1/2 = 97-1/8 inches of wall.
• That leaves room for a drywall ceiling and a finished height near 8 feet.

Studs for a 9-foot wall are commonly precut to 104-5/8 inches. Check the plan's wall height before you order or cut.

Walls on a Slab

When a bearing wall sits on concrete, the bottom plate must be pressure-treated, or you need a moisture barrier between it and the slab, such as a sill seal. Bolt it down at the code spacing. Use hot-dip galvanized or stainless fasteners. An untreated plate on concrete wicks moisture and rots.

Headers and Rough Openings

A header carries the load above an opening to the jack studs beside it. Sizes come from the plan or the code's header tables, which depend on span, roof load and the number of floors above.

In a 2x4 wall, a typical header is two 2x members with a 1/2-inch spacer of plywood or OSB between them. That brings it to 3-1/2 inches, the same as the wall thickness. In a 2x6 wall, it is usually three members or an engineered header.

Rough opening (RO) is the framed hole. Doors and windows need clearance for shims and insulation.

• Windows: use the RO in the window schedule. Many units are about 1/2 inch larger than the window in each direction.
• Doors: a standard door opening is about 2 inches wider than the door, and about 82-1/2 inches tall from the subfloor for a 6-foot-8 door. Check the door's specs.

Worked example. You are framing a 36-inch door in a 2x4 wall.

• RO width = 36 + 2 = 38 inches.
• Add one jack stud on each side: 38 + 1-1/2 + 1-1/2 = 41 inches.
• Add one king stud on each side: 41 + 3 = 44 inches.
• Header length = RO width + two jack studs = 41 inches.

If a header span is long, the plan may call for two jack studs on each side. Follow it.

Below a window, the rough sill sits on short jack studs and cripples. Above the header, cripples fill the space and keep layout going, so sheathing and drywall have something to nail to.

Corners and Intersections

Every inside corner needs something for drywall to attach to, and the corner should still have room for insulation.

• Three-stud corner. The traditional corner uses a stud on each wall plus blocks or an extra stud. It is strong, but leaves a void that is hard to insulate.
• California corner (two-stud corner). Turn one stud flat, set back from the end, to leave space. This allows insulation in the corner cavity while still providing drywall backing.
• T-intersection. Where an interior wall meets another wall, use a ladder (flat 2x blocks between studs at about 24 inches) or a pair of studs. Ladder blocking leaves room for insulation on an exterior wall.

Fireblocking stops flames from racing up hollow spaces. The code requires it at certain points, such as at floor and ceiling levels and in stud spaces over 10 feet tall. Know where your plan calls for it.

Building a Wall

Follow this sequence. It is how experienced crews work in platform framing.

1. Cut the plates. Snap wall lines on the deck. Cut top and bottom plates to length, and lay them next to each other. Join long walls so joints land on a stud.
2. Lay out. Mark openings first, then studs at 16 inches on center from the corner, on both plates at once. Mark kings, jacks and cripples.
3. Stud and header. Spread the plates apart. Set studs and openings between them, crowns all one way. Nail through the plates into stud ends. Nail kings and jacks together, and set the header.
4. Sheath. Square the wall on the deck by matching diagonals, and tack the bottom plate. Sheath it while it lies flat if it can still be lifted. Cut out openings later.
5. Raise and brace. Stand the wall on its lines. Brace it right away.
6. Plumb and align. Plumb the corners, then string the top of the wall and straighten it.
7. Nail to the deck. Nail the bottom plate into the floor framing. Add the second top plate.

Sheathing

Wall sheathing stiffens the wall and resists racking from wind. Most walls use 7/16-inch OSB or plywood.

• For a standard wall, nail at 6 inches on edges and 12 inches in the field, into studs at 16 inches on center. Common fasteners are 8d nails. High-wind and shear walls use tighter patterns. Follow the plan.
• Leave a 1/8-inch gap between sheets, unless the panel says otherwise.
• Do not overdrive nails. A nail head pressed through the top layer loses much of its strength.
• Keep nails at least 3/8 inch from panel edges.
• A shear wall is a wall that resists sideways forces. It has its own schedule and hardware. Do not change or skip any of it.

Standing a Wall

Warning: A long sheathed wall can weigh several hundred pounds. Plan the lift. Do not stand in the path of a wall that could tip back, and do not lift alone. Use wall jacks for a heavy wall.

1. Check the path. Clear the deck. Everyone must know the plan and who is calling the lift.
2. Set stops. Nail 2x blocks at the edge of the deck so the bottom plate cannot slide off.
3. Lift together. Use your legs. Stay spaced evenly along the wall.
4. Stop at the top. Keep people on the wall until braces are nailed in. Never let go of a wall that is not braced.
5. Protect the edge. On an upper floor, workers near the edge of a floor 6 feet or more above the level below need fall protection, such as guardrails or personal fall arrest.

Plumbing and Lining

Plumb means truly vertical. Line means straight along its length.

1. Plumb each corner with a long level or a laser. Check two directions. Brace it there.
2. Stretch a string along the top plate at a corner, held out by 3/4-inch blocks at each end.
3. Slide a third 3/4-inch block along the string. Where the wall is off, push it in or pull it out until the gap is right.
4. Hold it with a brace that is nailed to a stud and to a block on the floor.

Do not remove braces until the structure above holds the wall.

Double Top Plates

The second top plate ties walls together. It overlaps at corners and intersections, so that the walls lock to each other.

• Offset end joints in the top plates by at least 24 inches.
• Nail through the upper plate at 16 inches on center.
• If a plumber or duct crew cuts more than half of the plate, the code requires a steel strap across the cut.

Cuts in Studs

Trades will cut your walls. Know the IRC limits:

Holes must stay at least 5/8 inch from the edge of the stud. Holes and notches cannot be at the same height. Metal plates are used to protect pipes and wires close to the edge.

Common Mistakes

Check Your Understanding

1. A window opening has short studs under the sill. What are they called, and what do they do?

Cripple studs. They carry the sill and keep the layout spacing so finishes have something to fasten to.

2. You are framing a 32-inch door. What is the RO width, and how long is the header with one jack on each side?

RO = 32 + 2 = 34 inches. Header = 34 + 1-1/2 + 1-1/2 = 37 inches.

3. A wall has been built, sheathed flat, raised and braced, and the corners are plumb. What comes next?

Line the top with a string and blocks, adjust the braces, nail the bottom plate to the deck, and lap the second top plate.

4. Why would a builder want a two-stud corner?

It leaves room for insulation in the corner while still giving drywall a place to attach.

5. A bearing stud in a 2x4 wall has a hole of 2 inches. Is that allowed?

2 divided by 3-1/2 is about 57 percent, so it is under the 60 percent limit, but it is over 40 percent. In a bearing wall, the stud must be doubled, and no more than two successive doubled studs can be bored that way.

Key Takeaways

• Jack studs carry the header. King studs run full height beside them.
• Cripple studs fill above headers and below sills and keep layout on 16-inch centers.
• The sequence is cut plates, lay out, stud and header, sheath, raise and brace, plumb and align, then nail to the deck.
• Sheathing is usually nailed 6 inches on edges and 12 inches in the field.
• Put a treated plate or a moisture barrier between wood and concrete.
• Plan every wall raise, and brace before anyone lets go.