Light-Gauge Selection
| Gauge | mm | Application |
|---|
| 25ga | 0.45 | Light partitions ≤3.0 m |
| 22ga | 0.68 | Standard commercial ≤4.0 m |
| 20ga | 0.84 | Tall walls ≤5.5 m, fire-rated |
| 18ga | 1.09 | Heavy commercial, structural transition |
Heavy-Gauge (Structural CFS)
| Gauge | mm | Application |
|---|
| 18ga | 1.09 | Light load-bearing, curtain wall infill |
| 16ga | 1.37 | Standard load-bearing, ext. curtain wall |
| 14ga | 1.73 | Heavy load-bearing, multi-storey |
| 12ga | 2.46 | Headers, jambs, tall curtain wall |
Structural = 345 MPa (50 ksi). Non-structural = 228 MPa (33 ksi). Verify stamp!
Tolerances & Spacing
| Item | Value |
|---|
| Default spacing (church) | 400 mm o.c. recommended |
| 600 mm o.c. | Non-rated partitions ≤3.0 m only |
| 300 mm o.c. | Very tall walls, tight curves |
| Stud spacing tolerance | ± 3 mm from layout |
| Plumb tolerance | Max 3 mm in 3 m |
| Track alignment (top/bottom) | Within 3 mm |
| Stud cut short of height | ~10 mm (non-load-bearing) |
| PAF spacing (floor track) | 600 mm o.c., 150 mm from ends |
Bridging Requirements
| Wall Height | Rows |
|---|
| >2.4 m | 1 row at mid-height |
| >3.6 m | 2 rows at third points |
| >4.8 m | 3 rows evenly spaced |
Fire-Rated Assemblies (ULC)
| Rating | Typical Assembly |
|---|
| 1-hr (U411) | 92mm, 22ga @ 600 o.c., 1 layer 15.9mm Type X each side, mineral wool |
| 2-hr (U412) | 92mm, 20ga @ 400 o.c., 2 layers 15.9mm Type X each side, mineral wool |
- Elec. box offset: min. 610 mm opposite sides
- Acoustic sealant at all perimeter joints
- Wall extends to structure — NOT to ceiling grid
- Fire stop all penetrations with listed system
- Insulation type must match ULC listing exactly
Sound Ratings (STC) — Church Spaces
| Adjacency | STC |
|---|
| Sanctuary to classroom | 55–60 |
| Between classrooms | 45–50 |
| Sanctuary to lobby | 50–55 |
| Office to office | 45–50 |
| Nursery to adjacent | 50–55 |
| Mech. room to occupied | 55–60 |
Double-stud wall (2 rows, 25mm gap, 2 layers each side, mineral wool) = STC 60–65.
Deflection Head Tracks
- Required on ALL non-load-bearing walls under steel/concrete
- Gap = calculated deflection + 10 mm tolerance
- Deep-leg track: 20–38 mm capacity typical
- Proprietary systems: up to 50 mm+ capacity
- DO NOT screw studs to top track
- Drywall stops 10–15 mm short of structure
- Seal gap with flexible acoustic sealant (not rigid)
- Fire-rated: mineral wool + intumescent sealant per ULC
Fastener Guide
| Screw | Use |
|---|
| TEK 1 (fine point) | Steel-to-steel ≤22ga |
| TEK 3 (drill point) | 20ga–14ga connections |
| TEK 5 (long drill) | 14ga–10ga, clip angles |
| Wafer head | Stud-to-track (flush for drywall) |
| HWH (hex washer) | Structural, clips, bridging |
| Type S drywall | Drywall to steel studs |
Drywall screws: 200 mm edges, 300 mm field. Confirm against ULC listing.
Safety — Do Not Forget
- 345 vs. 228 MPa: ALWAYS verify steel grade stamp on bundle. Wrong grade = 35% less capacity.
- Deflection tracks: Never screw studs to top track. Mark tracks with flags/tape to prevent accidental fastening.
- Fire-rated walls to structure: Walls stopping at ceiling grid = zero fire separation above ceiling.
- Grommets on all wiring holes (CEC Rule 12-516). Sharp steel edges cut through wire insulation.
- No field holes with grinder or torch. Use step bit, hole saw, or hydraulic punch only.
- Steel shims only under tracks — never wood. Keep 1.5, 3, 6 mm shims on site.
- PAT certification required for powder-actuated tools. Check slab thickness before firing.
Pro Tips
- Default to 22ga minimum — negligible cost vs. 25ga, much stiffer walls.
- Install bridging before drywall crew arrives — never skip it.
- Set screw gun clutch to drive flush, not through steel.
- Use cold-cut saw (carbide blade) — never abrasive cut-off wheels on galvanized steel.
- Curved walls: snip spacing by radius — >3 m: 100–150 mm; 1.5–3 m: 50–75 mm; <1.5 m: 25–50 mm.