Alabama Metal Stud and Drywall Contractor

Key Concepts

Quantity Takeoff for Gypsum Board - Calculate wall area (length × height), then divide by panel size (typically 4×8, 4×10, or 4×12 SF) to get board count. Add 10–15% waste factor for cuts and openings. - Ceiling areas are calculated separately from walls; panel orientation (parallel vs. perpendicular to framing) affects fastener counts and seam locations.

Metal Framing Estimation - Track (runner) quantity: perimeter of each wall × 2 (top and bottom), converted to linear feet, then divide by piece length (typically 10'). - Stud quantity: [(wall length ÷ stud spacing) + 1] × number of walls. Add extras for corners, door/window jambs, and headers. - Common stud spacings: 16" o.c. and 24" o.c. Know how spacing affects both stud count and screw frequency.

Screw and Fastener Calculations - Screws per panel depend on framing spacing and panel orientation: - 16" o.c. framing: approximately 32 screws per 4×8 panel (field + edges) - 24" o.c. framing: fewer field fasteners, but edge fastening remains consistent - Minimum fastener spacing to edges: 3/8" from panel edge; field screws typically 12" o.c. in the field, 8" o.c. at edges/ends - Double-layer systems require separate fastener calculations for base and face layers

Reading Construction Documents - UL Assembly designations appear in specifications and on drawings (e.g., UL U305, UL L501). The "U" prefix = wall assembly; "L" prefix = floor/ceiling assembly. - Specifications indicate required STC, IIC, NRC, and CAC ratings — read Division 09 specs carefully. - Limiting height tables are published by framing manufacturers and referenced on structural drawings; they are based on stud gauge, depth, spacing, and allowable deflection (L/120, L/240, L/360).

Key Concepts

Gypsum Panel Types and Thicknesses - Standard drywall thicknesses: 1/4", 3/8", 1/2", 5/8". For most wall and ceiling applications, 1/2" is standard; 5/8" Type X is required for fire-rated assemblies. - Type X (fire-resistant) contains glass fibers and special core additives to slow burn-through; required in 1-hour and 2-hour rated assemblies. - Type C is an enhanced Type X with greater fire resistance per thickness. - Moisture-resistant (MR/green board) and mold-resistant (purple board) panels are designated for wet or humid areas but are NOT a substitute for cement board in wet shower surrounds.

Steel Stud and Runner Selection - Studs are designated by width, type, and gauge (mil thickness). Common widths: 1-5/8", 2-1/2", 3-5/8", 4", 6". - Gauge/mil designations: 25 gauge (18 mil) = light duty/non-load-bearing; 20 gauge (33 mil) and 18 gauge (43 mil) = heavier applications. - Runners (tracks) receive the studs at top and bottom; studs are NOT mechanically fastened to tracks in non-load-bearing walls (allows for deflection). - Deflection track (slotted) is used at top of partitions beneath structure to accommodate floor live load deflection.

Fasteners - Drywall screws for wood framing: Type W (coarse thread), minimum 1-1/4" for single layer 1/2" board into wood. - Drywall screws for metal framing: Type S (fine thread, self-drilling) for studs up to 20 gauge; Type S-12 for heavier gauge steel. - Screw length rule: fastener must penetrate framing minimum 5/8" for wood, 3 threads for metal studs. - Nails (for wood framing only): 1-3/8" cooler/drywall nails minimum for 1/2" board; 1-5/8" for 5/8" board.

Key Concepts

Levels of Gypsum Board Finish (GA-214, ASTM C840)

Five industry associations (AWCI, CISCA, GA, DWFC, PDCA) collaborated to define standardized finish levels:

• Level 0 – No taping, finishing, or corner beads required. Temporary construction or undecided decoration.
• Level 1 – Joint tape embedded in compound; tool marks and ridges acceptable. Used in plenum areas, attics, concealed spaces, service corridors ("fire taping" areas). Does not typically meet fire-resistant assembly requirements.
• Level 2 – Tape embedded plus one coat of compound over joints, angles, fasteners, and beads; tool marks acceptable. Used where water-resistant board is substrate for tile, or in garages and similar low-visibility areas.
• Level 3 – Tape embedded plus two separate coats over joints/angles/beads/fasteners; surface free of tool marks. Used under heavy-texture or skip-trowel finishes and medium-weight wall coverings.
• Level 4 – Tape embedded plus three separate coats; smooth, uniform surface. Standard for most painted surfaces, light-texture finishes, and lightweight wall coverings. Most common specification.
• Level 5 – Level 4 plus a skim coat (thin coat of joint compound or proprietary material) over entire surface. Required for critical lighting conditions, gloss or semi-gloss paints, and high-end finishes.

Embedding Joint Tape

• Apply a bed coat of joint compound over the flat joint first, then embed the tape and smooth with a joint knife, leaving a thin coating of compound over the tape.
• At interior angles, fold tape and embed in compound; wipe each side separately to leave a thin coat.
• Tape must be fully bedded — no bubbles or voids beneath it.

Key Concepts

One-Piece Metal Door Frame Installation One-piece (welded) metal door frames must be anchored at the floor with floor anchors (minimum 2 per jamb) and secured to wall studs at each hinge and strike location. Frames in drywall partitions require at least 3 wall anchors per jamb. The frame must be set plumb, level, and square before drywall installation begins. In fire-rated assemblies, the frame must be listed and labeled to match the required opening protection rating.

Curved Surfaces & Arch Gypsum Board Application Gypsum board can be bent to curved surfaces using either the dry or wet method. Dry bending works for gradual curves; wet bending (moistening the paper face and core) allows tighter radii. Minimum bending radii depend on board thickness and direction of bend: - 1/4" board bent the short way: ~5 ft radius; long way: ~15 ft radius - 3/8" board short way: ~7.5 ft; long way: ~25 ft Apply the board with the face (finish) side toward the curve for concave surfaces; face away for convex. Use closer fastener spacing on curved applications.

Exterior Ceiling Board & Weather Protection Exterior soffit and ceiling applications require exterior-rated gypsum board (e.g., DensArmor, fiberglass-mat faced, or equivalent exterior board). Standard interior gypsum board is not permitted in exposed exterior locations. Board must be protected from direct water contact; all joints and fasteners must be sealed. Framing must allow drainage and ventilation to prevent moisture accumulation.

(5 Questions, 12% of Exam)

Key Concepts

Personal Protective Equipment (PPE) — 29 CFR 1926.20(f)

• Employer must provide PPE to each individual employee — every failure to provide PPE to a single employee is a separate OSHA violation
• Required PPE for drywall work: hard hats (head protection), safety glasses/goggles (eye protection), N95 or higher respirators (silica/dust exposure)
• Respiratory protection is mandatory when silica dust levels exceed permissible exposure limits (PEL); engineering controls (wet methods, ventilation) must be tried first

Silica Dust & Hazardous Materials

• Crystalline silica exposure is a serious hazard when cutting, sanding, or grinding drywall and joint compound — causes silicosis
• Plaster burn: calcium hydroxide in joint compounds is caustic; requires gloves and eye protection; prolonged skin contact causes chemical burns
• Mold/mildew: use appropriate respirators (N95 minimum) and gloves when disturbing mold-affected materials
• Per §1926.21(b)(3): employees handling caustic/harmful substances must be instructed on safe handling, hygiene, and required PPE

Fall Protection — 29 CFR Subpart M

• Fall protection required at 6 feet or more above a lower level on construction sites
• Three acceptable systems:
• Guardrail systems: top rail at 42 inches (±3 in.), mid-rail at 21 inches, capable of withstanding 200 lbs force
• Safety nets: installed as close as practical below work surface, no more than 30 feet below
• Personal fall arrest systems (PFAS): harness, lanyard, anchor point rated at 5,000 lbs per employee; must stop a fall within 3.5 feet and limit arrest force to 1,800 lbs