Drywall / Gypsum Board Inspection

Per NBC 9.29 and GA-216, framing members must be spaced at maximum 400 mm o.c. for 12.7 mm board or 600 mm o.c. for 15.9 mm board. Framing must be straight, plumb, and free of twists exceeding 5 mm across the face. Backing must be provided at all board edges, corners, and penetrations. Vapour barrier must be installed per NBC 9.25.4 before board application.

1. Verify stud spacing matches board thickness requirements per GA-216

2. Check framing for straightness — maximum 5 mm bow or twist across face

3. Confirm backing is provided at all corners, intersections, and board edges

4. Verify vapour barrier is continuous and sealed per NBC 9.25.4 before boarding

5. Check that all electrical boxes, blocking, and backing for fixtures are in place

- Studs bowed or twisted causing uneven drywall surfaces

- Missing backing at inside corners or ceiling-wall junctions

- Vapour barrier not continuous or damaged during framing

- Electrical boxes protruding beyond planned drywall surface

Per NBC 9.29 and CSA A82.31, board type must match the application. Type X (fire-rated) 15.9 mm board is required where fire resistance ratings are specified per NBC 3.1.7. Moisture-resistant board (green board) or cement board must be used in areas of intermittent moisture per NBC 9.29.5. Regular 12.7 mm board is acceptable for standard interior applications.

1. Verify board type matches specified application — Type X where fire ratings required per NBC

2. Check that moisture-resistant or cement board is used behind tub/shower surrounds

3. Confirm board thickness meets fire rating requirements per ULC listings

4. Verify board is stored flat, dry, and acclimatized before installation

5. Check that all boards are free from damage, water stains, or mold before installation

- Regular board used where fire-rated Type X is required by the fire rating

- Standard drywall used in high-moisture areas instead of moisture-resistant board

- Damaged or water-stained boards installed rather than rejected

- Board thickness insufficient for the specified fire resistance rating

Per GA-216 and NBC 9.29, screws must be spaced at maximum 300 mm o.c. on ceilings and 400 mm o.c. on walls for single-layer application. Screws must penetrate wood framing by 25 mm minimum and steel studs by 10 mm. Screw heads must be set slightly below the paper surface without breaking the paper face. Adhesive may supplement but not replace mechanical fasteners.

1. Check screw spacing — maximum 300 mm on ceilings, 400 mm on walls per GA-216

2. Verify screw depth — set just below paper surface without breaking paper face

3. Confirm screws are at least 10 mm from board edges and 15 mm from board ends

4. Check that no screws are loose, popped, or protruding above the surface

5. Verify screw penetration depth into framing (25 mm wood, 10 mm steel minimum)

- Screws over-driven breaking the paper face, reducing holding power

- Screw spacing exceeds maximum, particularly on ceilings

- Screws too close to board edges causing edge crumbling

- Screws not hitting framing members (spinning screws)

Per GA-216 and CSA A82.27, joints must be taped and finished to the specified level (1 through 5). Level 4 is standard for painted surfaces, requiring three coats of compound over tape with feathered edges. Paper tape is required at all flat joints and inside corners. Finished joints must be smooth with no visible ridges, crowns, or depressions under raking light conditions.

1. Verify the specified finish level (typically Level 4 for painted walls, Level 5 for critical lighting)

2. Check flat joints with a 1200 mm straightedge — no ridges or depressions exceeding 3 mm

3. Inspect under raking light for visible tape edges, tool marks, or compound ridges

4. Verify inside corners are properly taped and finished with smooth intersection

5. Confirm all screw heads are covered with minimum two coats of compound

- Visible joint lines under raking light from insufficient feathering

- Tape bubbles or delamination from inadequate bedding compound

- Excessive joint compound buildup creating crowns at joints

- Inside corners showing cracks from paper tape not properly embedded

Per NBC 3.1.7 and 9.10.3, fire-rated wall and ceiling assemblies must be constructed exactly per ULC-listed designs. All penetrations through fire-rated assemblies must be firestopped per NBC 3.1.9 using ULC-listed firestop systems. Fire-rated assemblies must extend continuously from floor slab to floor slab above, and joints must be sealed with rated joint systems.

1. Verify fire-rated assembly matches ULC listing — correct board type, thickness, and number of layers

2. Check that all penetrations (pipes, cables, ducts) are firestopped with ULC-listed materials

3. Confirm fire-rated walls extend continuously from slab to slab above (not stopping at ceiling)

4. Verify electrical boxes in fire-rated walls are listed for the application and properly spaced

5. Check that rated joint systems are installed at all head-of-wall and perimeter joints

- Fire-rated assembly constructed with wrong board type or thickness

- Penetrations not firestopped or sealed with non-rated materials

- Fire-rated walls terminated at suspended ceiling instead of extending to structure above

- Electrical boxes in fire-rated walls not meeting spacing or listing requirements

Per NBC 9.25.3 and 9.29.5, drywall installation must account for moisture conditions. Interior relative humidity during installation should be below 70%. Board must not be installed on surfaces with moisture content exceeding manufacturer limits. In areas subject to intermittent moisture (bathrooms, kitchens), appropriate moisture-resistant products must be specified.

1. Verify ambient relative humidity is below 70% before and during installation

2. Check that framing moisture content is below 19% before boarding per NBC 9.3.2

3. Confirm moisture-resistant products are used in designated wet areas

4. Verify adequate ventilation is provided during joint compound drying

5. Check that no condensation or moisture is present on surfaces before board application

- Board installed over wet framing causing mold growth behind walls

- Joint compound applied in cold or humid conditions preventing proper drying

- Standard board used in areas subject to moisture or condensation

- Inadequate ventilation during construction causing elevated moisture levels

Per GA-216 and CSA A82.31, the completed drywall surface must be uniform, smooth, and free of defects before priming and painting. All joints, fastener heads, and accessories must be properly finished to the specified level. Corner bead must be straight with no dents or kinks. Sanding dust must be removed before priming.

1. Inspect all surfaces under raking light from multiple directions to identify ridges, depressions, or tool marks

2. Check corner bead for straightness using a 1200 mm straightedge — no gaps greater than 3 mm

3. Verify all nail/screw pops are addressed and no fastener heads are visible or protruding

4. Confirm sanding is complete and all dust has been removed from surfaces

5. Check that all trim accessories (J-bead, L-bead, reveal trim) are straight and properly finished

- Joint ridges or depressions visible under raking light

- Corner bead dented during construction or poorly finished

- Sanding dust left on surface causing paint adhesion issues

- Screw pops appearing after initial finishing due to wood shrinkage