The Drywall & Framing Glossary: 100+ Terms, Defined the Way the Trade Uses Them

A

Abuse-Resistant Board

Gypsum panel with a reinforced core and heavier face paper for corridors, schools and healthcare where walls take impact; specified where standard board would fail in service.

Acoustical Sealant

Non-hardening caulk applied at partition perimeters and penetrations to preserve an assembly's STC rating; skipping it can drop a tested wall by several points.

Area Separation Wall (ASW)

A 2-hour rated shaftliner wall between townhome units, built with H-studs and breakaway clips so one burning unit can collapse without pulling down its neighbor.

ACT (Acoustical Ceiling Tile)

Lay-in ceiling tile in an exposed tee grid; quantified by tile count, grid components, wall angle and hanger wire per ceiling type.

Addendum

A formal change to bid documents during the bid period; every addendum can move quantities, so takeoffs are revised to the documents of record.

B

Backing

Flat stock or plates inside a wall to anchor casework, rails, TVs and fixtures; miss it in the takeoff and someone opens finished walls later.

Backer Rod

Foam rod pressed into joints before sealant to control depth; counted by LF at sheathing transitions, tubs and control joints.

Bid Leveling

Comparing subcontractor bids against an independent quantity takeoff to find scope gaps instead of just price differences.

Bill of Materials (BOM)

The consolidated order list produced from a takeoff - items, dimensions and quantities in supplier-ready units.

Bulkhead

A framed and boarded ceiling drop, usually chasing ductwork or defining a space edge; framed, boarded and finished as its own condition.

Butt Joint

Where two non-tapered board ends meet; harder to finish flat than tapered joints, which is why layout minimizes them.

C

C-H Stud

The stud used in shaft wall systems, shaped to grip 1-inch shaftliner panels between drywall layers on the room side only.

Cement Board

Cementitious backer (Durock, HardieBacker) behind tile at wet areas; counted separately from gypsum because it prices and hangs differently.

Control Joint

A designed break in large drywall surfaces to absorb movement; typically required around 30 feet in walls and specified in details.

Corner Bead

Metal, vinyl or paper-faced angle protecting outside corners; counted by LF and converted to sticks.

Cross Tee

The short grid member spanning between main tees in suspended ceiling systems, both ACT and drywall grid.

CSI Division 09

The MasterFormat division holding finishes; drywall assemblies live mainly in 09 21 16 and 09 29 00.

D

Deflection Track

Top track with extended legs letting structure above move without loading the studs; required at decks and slabs, priced separately from standard track.

Demising Wall

The wall separating tenants or units; often rated for fire and sound, and often the most expensive partition type on the job.

DensGlass

Georgia-Pacific's glass-mat gypsum sheathing for exterior and pre-rock conditions; moisture and mold resistant, priced well above standard board.

Drywall Grid

Concealed suspension system (mains and tees) that gets boarded and finished - the skeleton of hard lids and drywall ceilings.

Draft Stopping

Material subdividing concealed attic and floor spaces to slow fire spread; a code scope that hides in sections, not plans.

Durock

USG's cement board brand; shorthand on many sets for any cementitious backer at tile.

E

End Stud

The stud terminating a wall run; every run gets one, which is why run count matters in framing math.

Exclusions

The proposal list stating what a bid does not cover; a professional takeoff makes exclusions deliberate instead of accidental.

Expansion Joint

Building-wide movement joint; where drywall crosses one, special trim and detailing apply.

F

Fire Taping

Level 1 finish - tape embedded in compound, no finish coats - required at rated assemblies in concealed spaces; inspected even where never seen.

Firestopping

Tested systems sealing joints and penetrations in rated construction: head-of-wall, pipes, conduits, perimeter containment - each to a listed system.

FlameBlock

LP's fire-rated OSB sheathing achieving ratings with fewer layers; appears in pre-rock and exterior conditions.

FRP (Fiberglass Reinforced Panel)

Washable wall panels over board in kitchens and washdown areas; counted with trims and adhesive.

FRT (Fire-Retardant-Treated)

Pressure-treated lumber/plywood for blocking where combustible material needs a flame-spread rating; costs multiples of untreated stock.

Furring

Channels or studs building a wall surface off concrete, masonry or existing construction; hat channel, Z-furring or studs flat.

Flexible Track

Curvable track for radius walls; a specialty item that must be counted, not improvised.

G

Gauge

Steel thickness designation - 25GA light interior through 16GA and heavier structural; mils are the modern equivalent (25GA≈18mil, 20GA≈33mil).

Gypsum Association (GA)

Industry body publishing GA-216 (application standards) and the GA-600 Fire Resistance Design Manual takeoffs reference.

Green Board

Legacy term for moisture-resistant board; modern MR board uses different tech but the name persists on drawings.

H

Hat Channel

Furring channel with a hat-shaped profile for leveling surfaces or furring masonry; also the rigid cousin of resilient channel.

Head-of-Wall

The joint where a rated wall meets the deck above; must accommodate deflection while maintaining the rating - a major firestopping line item.

Hanger Wire

Wire suspending ceiling grid from structure; counted by drop length and spacing with anchors.

High Wall

Any wall exceeding normal limiting heights, demanding heavier gauge, deeper studs or engineering - gyms, atriums, warehouses.

I

ICRA

Infection Control Risk Assessment - healthcare protocols dictating containment and phasing; a quantifiable scope on hospital work.

Impact-Resistant Board

Panel rated under ASTM C1629 for soft/hard body impact; classification levels appear in specs for corridors and gyms.

In-Wall Blocking

See Backing; the drawings' term varies but the scope is the same.

J

J-Bead

Trim finishing a board edge where it meets dissimilar material, J-shaped in section; counted by LF.

J-Track

The track receiving shaftliner panels at shaft wall perimeters and jambs.

Jamb Stud

Stud framing a door or window opening; typically doubled or heavier gauge, counted per opening.

Joint Compound

The mud - taping, all-purpose, lightweight and setting-type compounds, quantified by finish level and area.

K

Kicker

Diagonal brace stabilizing framing back to structure - soffits, high walls, furred walls; a real material and labor line.

King Stud

Full-height stud alongside jamb studs at openings.

Knock-Down (KD) Frame

Three-piece metal door frame installed after board; affects framing and board sequence at openings.

L

Level 5 Finish

Skim coat over the entire surface above Level 4; required at critical lighting and gloss paints, roughly doubling finishing effort.

Light Gauge Steel Framing

Cold-formed steel studs and track for non-structural (and some structural) framing - the drywall contractor's skeleton scope.

Limiting Height

Maximum wall height for a given stud size, gauge and spacing per deflection criteria; exceed it and the wall needs redesign.

Liner Panel

1-inch Type X gypsum shaftliner used in shaft wall and ASW systems.

M

Main Tee

Primary suspension member in grid ceilings, hung from structure by wire.

Mineral Wool

Stone-fiber insulation for fire and acoustic performance; denser and pricier than fiberglass with far lower per-bag coverage.

MR Board

Moisture-resistant gypsum for wet-adjacent areas; distinct from cement board, which goes behind tile.

MLF

Thousand linear feet - the unit steel framing is often priced in.

Mud Ring

Slang for adjustable box extension; matters to drywall at deep double-layer assemblies.

N

NLB (Non-Load-Bearing)

Framing carrying only its own weight and finishes - most interior drywall framing.

Nailer

Wood or steel member installed to receive another trade's attachment; a backing scope by another name.

O

O.C. (On Center)

Spacing measured center to center - 16" o.c. studs, 24" o.c. channel; the number that drives framing quantities.

One-Hour Wall

Common shorthand for a 1-hour fire-rated assembly; the rating belongs to the tested assembly, not the board alone.

P

Party Wall

The rated, sound-controlled wall between dwelling units; multi-family's defining assembly.

Perimeter Fire Containment

Firestopping the gap between floor slab edge and curtain wall - safing insulation plus spray, a specialized scope.

Plenum

The space above a ceiling used for air return; plenum-rated requirements affect materials there.

Prerock

Board installed early behind tubs, at plumbing walls and above hard lids - first board on the job, on someone else's schedule.

Punchout

The factory hole in stud webs for services; also why our tally-mark logo reads as studs to framers.

Putty Pad

Intumescent pad wrapping electrical boxes in rated walls; counted per box.

Q

Quantity Takeoff

The measured extraction of material quantities from drawings - the product this entire site is about.

R

RC-1 / Resilient Channel

Spring-steel channel decoupling board from framing to boost STC; single-leg design, easily short-circuited by wrong screws, quantified by LF per assembly.

Rated Assembly

A wall or ceiling built exactly to a tested, listed design (UL, GA) achieving a fire rating; the listing governs every component.

RCP (Reflected Ceiling Plan)

The drawing showing ceilings as if mirrored on the floor - where ceiling scopes live.

Rock

Trade slang for gypsum board; 'rocking' is hanging it.

RFI (Request for Information)

The formal question to the design team; good takeoffs generate RFIs before bid instead of change orders after.

S

SAB / SAFB (Sound Attenuation Fire Batts)

Mineral fiber batts for acoustic (and fire) performance in partitions; specified by thickness, quantified per assembly.

Safing

Mineral wool packed at slab-edge gaps as part of perimeter fire containment.

Scope Gap

Work no one carried - discovered at bid leveling if you're lucky, at construction if you're not.

Shaft Wall

Rated wall system built from one side (shaftliner + C-H studs + face layers) enclosing elevators, stairs and chases.

Shaftliner

See Liner Panel.

Sheathing

Panels on the framing exterior - DensGlass, FlameBlock, plywood - the envelope edge of drywall scope.

STC (Sound Transmission Class)

Single-number acoustic rating of an assembly; multi-family and hotel specs set minimums that drive channel, batts and layers.

Stick

One piece of trim or bead at stock length; 'sticks' is how bead is ordered.

Stud

The vertical framing member; in this trade, cold-formed steel by web size and gauge.

T

Taper

The factory-thinned long edge of board that lets joints finish flat; also the finisher who tapes them.

Track

The horizontal channel receiving studs top and bottom; quantified separately from studs, with deflection track on its own lines.

Type C Board

Enhanced fire-rated gypsum outperforming Type X in some assemblies, especially ceilings; not interchangeable with X where the listing says C.

Type X Board

5/8" fire-rated gypsum, the workhorse of rated assemblies.

Tenant Improvement (TI)

Fit-out of leased space; fast-cycle bidding where drywall is usually the biggest trade.

Takeoff Sheet

The organized quantity document a takeoff produces - per wall type, per floor, supplier-ready.

U

UL Assembly

A fire-rated design listed by UL (e.g., U419); drawings cite the number and the takeoff quantifies to it.

Unit Matrix

Multi-family method: takeoff each unit type once, extend by the unit count schedule.

V

Vapor Retarder

Membrane controlling moisture diffusion - poly or smart membranes like MemBrain - quantified by roll coverage where in drywall scope.

Veneer Plaster

Thin plaster over blueboard; a different finishing system occasionally specified in institutional work.

W

Wall Angle

Perimeter trim of suspended ceilings, L-shaped, counted by room perimeter.

Wall Type Schedule

The drawing legend defining every partition assembly - the single most important sheet in a drywall takeoff.

Waste Factor

The percentage added over net quantities for cuts and breakage - typically 7-15% for board, shown separately in honest takeoffs.

Wet Wall

Wall containing plumbing; triggers MR board, prerock and access considerations.

Z

Z-Furring

Z-profile channel attaching rigid insulation and board to masonry or concrete walls.

Zip Strip

Tear-away bead giving a clean caulk joint where board meets windows and dissimilar materials.

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