Gypsum Board Ceilings

Summary

Gypsum board ceilings are layers of gypsum panels fastened to framing or a suspended grid and finished with joint compound, giving a seamless ceiling that can be fire rated and painted. Ceilings sag and show joints under raking light, so settle board thickness, framing spacing, level of finish, and control joints before drawing the ceiling.

Cols

Image

Level of finish (GA-214): Levels 0 to 5 for tape, joint compound, and surface preparation
Sag-resistant board: 1/2 in. ceiling board made to resist sag
Perimeter relief: separation or slip connection between ceiling and wall that lets the ceiling move
Control joint: break in the board and finish that relieves cracking
Resilient channel: metal channel that decouples the board from framing

Standards

Levels of finish (GA-214)

Level 0: no taping, finishing, or accessories; temporary work
Level 1: tape embedded in joints and angles; areas not open to public view and smoke barriers
Level 2: tape, one thin coat over joints, and one over fasteners; tile substrate, garages, and storage
Level 3: tape, a wiped coat, and a second coat over joints; two coats over fasteners; heavy or medium textures and heavy-duty wallcoverings
Level 4: two coats over flat joints, one over angles, three over fasteners; smooth surfaces under flat paint, light textures, and wallcoverings
Level 5: Level 4 plus a skim coat over the whole surface; gloss or dark paints and critical lighting

Test and installation standards

ASTM C840: application and finishing of gypsum board
GA-216: application and finishing of gypsum panel products
ASTM C1396: gypsum board product standard
GA-214: recommended levels of finish

Detailing

Use 1/2 in. sag-resistant board where there is a water-based texture, 24 in. framing, or load over about 1.3 psf; 5/8 in. board is used at 24 in. framing
Run board perpendicular to framing to reduce sag; this also performs better in fire tests
Specify Level 5 on ceilings, since low-angle light shows joints and imperfections
Add control joints at 30 ft; with perimeter relief the spacing can extend to 50 ft
Decouple the ceiling with resilient channel where framing movement could crack it
Coordinate fire rating, penetrations, and access panels with the assembly tested

Uses

Specific uses

Residential and commercial ceilings
Soffits, bulkheads, and drops
Fire-rated ceiling assemblies
Curved and coffered ceilings

Pros and cons

Pros

Continuous, paintable surface
Can be part of fire-rated assemblies
Moderate cost and well known to the trades

Cons

Sags at wide framing spacing and under heavy loads
Joints and fasteners show under raking light unless Level 5 is used
Hard to access for later work above

Manufacturing and cost

Construction

Panels are screwed to framing or a suspended grid, taped, and finished in coats of joint compound
Finishing follows the specified level and is sanded between coats

Main manufacturers and suppliers

Trade association: Gypsum Association.

Sources

National Gypsum: ceiling drywall tips and questions, https://nationalgypsum.com/ngconnects/blog/building-knowledge/ceiling-drywall-tips-questions
National Gypsum: five levels of gypsum board finish, https://nationalgypsum.com/ngconnects/blog/building-knowledge/gypsum-board-finish-levels
CISCA: copy of Gypsum Association GA-214-2021 levels of finish, https://cisca.org/files/GA-214-2021.pdf
Armstrong: hanging and framing flat ceilings technical guide, https://direct-www.armstrongceilings.com/content/dam/armstrongceilings/commercial/north-america/technical-guides/hanging-framing-flat-ceilings-technical-guide.pdf
Department of Veterans Affairs: 09 29 00 gypsum board, https://www.wbdg.org/FFC/VA/VAASC/VA 09 29 00.pdf