Wall stud

A typical Wall section in Platform framing
1. Cripple
2. Window Header
3. Top Plate / Upper Wall Plate
4. Window Sill
5. Stud
6. Sill Plate / Sole Plate / Bottom Plate

Steel studs in a wall

A wall stud is a vertical framing member in a building's wall of smaller cross section than a post. They are a fundamental element in building framing.

Etymology

Stud is an ancient word related to similar words in Old English, Old Norse, Middle High German, and Old Teutonic generally meaning prop or support. Other historical words with similar meaning are quarter, and scantling, (one sense meaning a smaller timber, not necessarily the same use). Stick is a colloquial term for both framing lumber (timber) and a "timber tree" (a tree trunk good for using as lumber (timber)). Thus the names "stick and platform", "stick and frame", "stick and box", or simply stick framing. The stud height usually determines the ceiling height thus sayings like: "...These rooms were usually high in stud..."

Purpose

Studs form walls and may carry vertical structural loads or be non load-bearing such as in partition walls which only separate spaces. They hold in place the windows, doors, interior finish, exterior sheathing or siding, insulation and utilities and help give shape to a building. Studs run from sill plate to wall plate. In modern construction studs are fastened to the plates in a way, such as using ties, to prevent the building from being lifted off the foundation by severe wind or earthquake.

Properties

Studs are usually slender so more studs are needed than in post and beam framing. Sometimes studs are long which is the defining characteristic of balloon framing, the studs extend two stories and carry a ledger which carries joists. Balloon framing has been made illegal in new construction in many jurisdictions for fire safety reasons because of the open wall cavities allow fire to quickly spread such as from a basement to an attic; the plates and platforms in platform framing providing an automatic fire stop inside the walls, and so are deemed much safer by fire safety officials. Being thinner and lighter, stick construction techniques are easier to cut and carry and is speedier than the timber framing.

In the United States studs were traditionally made of wood, usually 2"×4" or 2"×6" dimensional lumber and typically placed 16 inches (406 mm) from each other's center, but sometimes also at 12 inches (305 mm) or 24 inches (610 mm). The wood needs to be dry when used or problems may occur as the studs shrink and twist as they dry out. Steel studs are gaining popularity, especially for non load-bearing walls, and are required in some firewalls.

Other terms

Studs used to frame around window and door openings are given different names, including

• king stud − stud to left or right of a window or door that is continuous from the bottom plate to the top plate
• trimmer or jack − stud to the left or right of a window or door that runs from the bottom plate to the underside of a lintel or header
• cripple stud - a stud located either above or below a framed opening, that does not run the full height of the wall
• post or column − a doubled or other integral multiple of a group of studs nailed side by side. Posts in walls are used at point loads such as long spans near a wide window or sliding door, etc.

A building technique mostly associated with Lincolnshire, England and parts of Scotland gets part of its name from the studs: mud and stud (stud and mud). This building method uses studs in a framework which is then totally covered with mud which resembles the building material cob. Another traditional building method is called stud and plaster where the plaster walls are held by lath on the studs. Studs are also the namesake of a type of timber framing called close studding.

Grades

Based on the American West Coast Lumber Inspection Bureau (WCLIB) grading rules, there is only one grade of stud: STUD. A stud is graded for vertical application, and its stress requirements and allowable visual defects reflect that application. A stud is most similar to a #2 grade, which is held to a higher standard during grading. The biggest difference between the two is the frequency, placement and size of knots and overall allowable wane.

Locating studs

When mounting an object such as a shelf to a wall and maximum strength is desired, the goal is to attach the object to the studs in the wall, as drywall or plaster will take significantly less weight.

Using a stud finder, one can easily locate studs in most walls, though this may not work on very thick plaster, or plaster walls built with wire-lath.

If a stud finder does not work or is unavailable, it is often the easiest to tap lightly on the wall with the underside of one's fist. The resonating vibration especially from plaster and drywalls is an indication for a cavity behind. Tapping against a stud usually results in considerably less vibration. Another practice is to use a hammer and lightly tap on the wall while listening for sound differences until the stud is found. A third option is to resort to trial and error. Drilling a hole into the wall with a masonry bit, the difference between hitting a stud and not will be clear. If a stud is not hit, the bit will punch through quickly, with no resistance after the plaster or drywall. If a stud has been hit, the bit will put up considerable resistance. The bit may still drill into the wood or the metal, but progress will be slower. This is more manifest with a masonry bit than a wood drilling bit. After the first stud is found, others will typically be found 16 inches (about 40 cm) in either horizontal direction.

See also

• Furring