This chapter covers the full range of theoretical and practical knowledge related to the installation of metal framing and furring for interior systems. For the Red Seal exam, you must master not only installation techniques, but also load calculations, regulatory spacing requirements, types of profiles, fastening methods, and the requirements of the National Building Code of Canada (NBC). This chapter is structured to follow the logic of the work: from material selection to final installation, including calculations and verifications.
Metal Profiles: Types, Dimensions, and Uses
Studs
Studs are the vertical members of the framing system. They are manufactured from galvanized sheet steel, typically with a thickness ranging from 0.45 mm to 1.2 mm (25 to 16 gauge). The nominal widths of studs are 38 mm, 64 mm, 92 mm, or 152 mm, corresponding respectively to widths of 1½", 2½", 3⅝", and 6".
Nominal Width (mm)
Actual Width (in)
Typical Use
38
1½
Light partitions, residential
64
2½
Standard partition, commercial
92
3⅝
Partition with plumbing/electrical
152
6
High acoustic performance partitions
Studs are equipped with perforations (punch-outs) of 32 mm or 38 mm in diameter, spaced 600 mm apart along the profile. These perforations allow for the passage of electrical conduits and pipes. The edges of the perforations are reinforced (turned back) to maintain the structural integrity of the stud.
Tracks or Runners
Tracks are the horizontal members (top and bottom) of the framing system. They have the same width as the corresponding studs, but their flange is shorter (typically 25 mm to 30 mm). Tracks receive the ends of the studs, which are inserted either by friction or with mechanical fastening.
Furring Channels
Furring is a profile shaped like a "hat" or a "Z", used to:
Create a flat surface over an irregular wall (masonry, concrete)
Create a service space between the structure and the finish
Level an existing ceiling
The "hat" channel typically measures 19 mm × 38 mm, with a thickness of 0.45 mm to 0.9 mm. The "Z" furring is used for direct attachments to concrete or masonry.
Angle Profiles
L-shaped angle profiles are used for:
Partition returns (T or L intersections)
Ceiling edge attachments
Skylight border supports
Spacing and Load Calculations
Stud Spacing
The standard stud spacing is 400 mm (16 in) or 600 mm (24 in) on center. The choice depends on:
The thickness and type of finish material (gypsum, tile, panels)
The height of the partition
Suspended loads (shelving, cabinets, equipment)
For 12.7 mm (½ in) gypsum board installed horizontally, the maximum spacing is 600 mm. For 15.9 mm (⅝ in) board, the spacing can also reach 600 mm, but the fastening must be reinforced.
Rule of thumb: For a standard-height partition (2,400 mm to 3,000 mm), use 400 mm spacing if you anticipate suspended loads or ceramic tile finishes. Use 600 mm for light partitions with no additional load.
Allowable Load Calculation
The allowable load of a stud depends on:
35.The width of the profile (38, 64, 92, 152 mm)
36.The thickness of the steel (gauge)
37.The spacing between studs
38.The clear height of the partition
Simplified formula for axial load (P):
P = A × F × S
Where:
A = cross-sectional area of the stud (mm²)
F = allowable stress of the steel (typically 160 MPa for galvanized steel)
S = safety factor (typically 0.6)
Example: 92 mm stud, 25 gauge (0.45 mm), 400 mm spacing, 2,400 mm height.
Approximate area = 92 mm × 0.45 mm × 2 (two flanges) + 38 mm × 0.45 mm = 82.8 + 17.1 = 99.9 mm²
P = 99.9 × 160 × 0.6 = 9,590 N ≈ 978 kg
This is the maximum axial load. In practice, for a standard partition, the actual load is much lower.
Calculating the Number of Studs
Number of studs = (Partition length ÷ Spacing) + 1
Example: 4,800 mm partition with 400 mm spacing.
Number = (4,800 ÷ 400) + 1 = 12 + 1 = 13 studs
Note: Add one additional stud for each opening (door, window) and for each partition intersection.
Fastening and Anchoring
Fastenings to Concrete and Masonry
Tracks and furring attached to concrete or masonry require appropriate anchors. Common types are:
Anchor Type
Use
Allowable Load
Expansion anchor (rawlplug)
Concrete, solid brick
Medium
Nail-in anchor
Concrete, concrete block
Low to medium
Chemical anchor (epoxy)
Cracked concrete, heavy loads
High
Concrete screw (Tapcon)
Concrete, brick, block
Medium to high
Fastener spacing rule: Track fasteners must be spaced no more than 600 mm on center, with a fastener within 150 mm of each end of the track.
Fastenings to Steel Structure
For attachments to structural steel, use:
Self-drilling screws, type #8 or #10
Tek screws with washers
Bolts for heavy loads
Fastenings to Wood Structure
For attachments to wood, use:
Wood screws, type #8 or #10, minimum length 32 mm
Ring shank nails for tracks
Flat-head screws for furring
Metal Partition Installation
Installation Procedure
73.Layout: Mark the partition location on the floor and ceiling using a chalk line or laser level. Verify squareness using the 3-4-5 method (or 6-8-10).
74.Track installation: Fasten the bottom track to the floor and the top track to the ceiling. Ensure the tracks are aligned vertically (plumb) and horizontally (level).
75.Stud installation: Insert the studs into the tracks, starting at the ends. Studs must be cut to a length 6 mm to 12 mm less than the finished height to allow for thermal expansion and to facilitate insertion.
76.Stud fastening: Screw the studs to the tracks using #8 screws, 9.5 mm (⅜ in) or 12.7 mm (½ in) long. One screw per flange, at each end.
77.Reinforcements: Install horizontal reinforcements (bridges) or wood blocking for load supports (shelving, sinks, grab bars).
Openings (Doors and Windows)
For door openings:
Install jamb studs (double studs) on each side of the opening
The header is formed from two nested tracks, cut to the width of the opening plus 76 mm (3 in) on each side
The header is fastened to the jamb studs with screws
Header height calculation:
Header height = Door height + 25 mm (clearance) + ceiling finish thickness
Example: 2,030 mm door, 12.7 mm ceiling finish.
Header height = 2,030 + 25 + 12.7 = 2,067.7 mm
Furring: Installation Techniques
Furring over Concrete or Masonry
90.Flatness check: Use a 2 m straightedge to detect irregularities greater than 6 mm.
91.Furring installation: Furring channels are attached vertically or horizontally depending on the application. For walls, furring is installed vertically, spaced at 400 mm or 600 mm.
92.Leveling: Use plastic or metal shims to level the furring channels. Shims must be placed at each fastening point.
93.Fastening: Attach the furring with expansion anchors or concrete screws. Fastener spacing is 400 mm maximum.
Suspended Furring (Ceilings)
For ceilings, furring can be:
Attached directly to the structure (wood or steel)
Suspended using threaded rods (hangers) and attachments
Hanger spacing calculation:
Maximum spacing: 1,200 mm in the direction of the furring
Maximum spacing: 1,200 mm perpendicular to the furring
First hanger within 150 mm of the wall
Formula for the number of hangers:
Number of hangers = (Length ÷ 1,200) × (Width ÷ 1,200)
Partitions and ceilings must meet fire resistance requirements (fire-resistance ratings, FRR) according to Article 3.1.7. of the NBC. Metal framing systems with Type X gypsum board finishes provide FRRs from 45 minutes to 2 hours depending on the configuration.
Configuration
FRR
64 mm studs, 12.7 mm Type X gypsum, one layer per side
45 min
64 mm studs, 15.9 mm Type X gypsum, one layer per side
1 h
92 mm studs, 15.9 mm Type X gypsum, two layers per side
2 h
Acoustic Insulation
The NBC (Article 3.3.3.) requires a minimum sound transmission rating for partitions separating dwelling units. The minimum Sound Transmission Class (STC) is 50 for partitions between units.
Factors influencing STC:
Stud thickness and spacing
Presence of acoustic insulation (mineral wool)
Number of gypsum board layers
Separation (independent studs or resilient clips)
Seismic Requirements
In seismic zones (Article 4.1.8. of the NBC), metal partitions must be fastened with seismic restraints:
Top tracks must be attached to the structure with slip tracks allowing vertical movement
Studs must be fastened to the tracks with shear screws at each end
Quantity and Material Calculations
Gypsum Board Calculation
Gypsum board area = 2 × (Length × Height) for a partition
Example: 4,800 mm × 2,400 mm partition.
Area = 2 × (4.8 × 2.4) = 2 × 11.52 = 23.04 m²
Number of 1,200 × 2,400 boards = 23.04 ÷ 2.88 = 8 boards
Add 5% for waste = 8 × 1.05 = 8.4 → 9 boards
Screw Calculation
Number of screws = (Gypsum board area ÷ 0.3) × 2
Example: 23.04 m² of gypsum board.
Number of screws = (23.04 ÷ 0.3) × 2 = 76.8 × 2 = 153.6 → 154 screws
Rule of thumb: Use approximately 30 screws per standard gypsum board (1,200 × 2,400).
Insulation Calculation
Insulation area = Length × Height × Number of sides
Example: 4,800 mm × 2,400 mm partition, insulation on both sides.
Area = 4.8 × 2.4 × 2 = 23.04 m²
Tools and Equipment
Cutting Tools
Nibbler: For cutting profiles without deformation
Tin snips: For straight cuts
Hacksaw: For precise cuts
Angle grinder: For quick cuts (watch for sparks)
Fastening Tools
Clutch screw gun: For installing gypsum board screws
Powder-actuated tool: For fastenings to concrete
Drill/driver: For self-drilling screws
Measuring and Checking Tools
Laser level: For layout and alignment
Chalk line: For long layout lines
Spirit level: For local checks
2 m straightedge: For checking flatness
Occupational Health and Safety
Specific Hazards
Cuts: The edges of metal profiles are sharp. Wear protective gloves.
Falls: Use scaffolding or platforms for overhead work.
Dust: Wear a respirator when cutting profiles.
Noise: Wear hearing protection when using power tools.
Material Handling
Metal profiles are heavy and bulky. Use proper lifting techniques.
Store profiles flat on supports to prevent deformation.
Common Pitfalls to Avoid
167.Forgetting additional studs at openings: Each opening requires double jamb studs and a header. Not planning for them leads to stability problems and difficulty fastening the door frame.
168.Cutting studs too short: Studs must be cut 6–12 mm shorter than the finished height. Cutting them too short compromises stability; cutting them too long makes insertion difficult.
169.Ignoring profile orientation: Studs must be installed with the perforations aligned horizontally to allow for the passage of conduits. Incorrect orientation complicates electrical and mechanical installation.
170.Neglecting seismic restraints: In seismic zones, the use of slip tracks is mandatory. Ignoring them can lead to structural failure during an earthquake.
171.Using screws that are too long or too short: Gypsum board screws must penetrate at least 10 mm into the metal. Screws that are too long penetrate through the profile; screws that are too short do not hold.
172.Confusing spacing requirements: 400 mm spacing is for heavy loads; 600 mm is for light loads. Not respecting the required spacing for the type of finish material leads to sagging.
173.Forgetting leveling shims: Furring over concrete must be leveled with shims. Without shims, the final surface will be uneven.
174.Not checking for squareness: A partition that is out of square (3-4-5 method) causes problems with door installation and finishes.
Summary
Metal profiles include studs (38, 64, 92, 152 mm), tracks, furring channels, and angles.
Standard stud spacing is 400 mm or 600 mm on center, depending on loads and finish type.
Fastenings to concrete require appropriate anchors, spaced no more than 600 mm apart.
Studs are cut 6 to 12 mm shorter than the finished height.
Openings require double jamb studs and a header made from nested tracks.
Furring over concrete must be leveled with shims.
Ceiling hangers are spaced no more than 1,200 mm in each direction.
The NBC requires specific FRRs depending on the use and configuration of partitions.
Seismic zones require seismic restraints (slip tracks).
Quantity calculations include a 5% allowance for waste.
Safety requires gloves, eye protection, and hearing protection.
Practice the calculations: Number of studs, gypsum board area, number of screws, number of hangers.
Know the NBC requirements: FRR, STC, seismic requirements.
Visualize the procedures: Layout, install tracks, insert studs, fasten, verify.
Identify common pitfalls: Spacing errors, improperly cut studs, insufficient fastenings.
Mastery of metal framing and furring is fundamental to the lather (interior systems mechanic) trade. Exam questions often focus on calculations, spacings, and code requirements. Make sure you fully understand the principles before moving on to the practice questions.
