Alabama Metal Stud and Drywall Contractor

Alabama Metal Stud and Drywall Contractor · 6 questions (15%)

Key Concepts

Quantity takeoff for partitions. Single-layer board on each side of a partition requires board area for both faces: 12,000 sq ft of partition wall = 24,000 sq ft of board (Gypsum Construction Handbook, Ch. 10 — Selection of Materials / Performance Requirements).

Screw usage varies with four variables. "The number of fasteners used to install gypsum board varies with framing spacing, screw spacing, panel orientation and panel size." Charts give screws per 1,000 sq ft, and "Allowance should be made for loss" (Appendix — Gypsum Board Screw Usage).

Material selection method. "Evaluation may be done through benefit-cost analysis or life-cycle cost analysis, which considers the total cost of an assembly throughout its useful life. Building materials selection should always be based on total performance, including maintenance, not simply on initial construction cost or a budgeted cost figure" (Ch. 10 — Selection of Materials).

Fire testing standard. All fire resistance tests are conducted per ASTM E119, "Standard Test Methods for Fire Tests of Building Construction and Materials," also known as ANSI/UL 263 and NFPA 251 (Ch. 10 — Fire and Sound Tests).

Key UL designations. - U305 (1-hr, wood): wood 2×4 studs at 16″ o.c., 5/8″ Firecode core panel each side; insulation: Optional. - U301 (2-hr, wood): two layers 5/8″ Firecode core each side; base layer 1-7/8″ cement-coated nails 6″ o.c., face layer 2-3/8″ nails 8″ o.c.; face-layer joints staggered over base-layer joints. - U419 (1-hr, steel): steel 362S125-18 minimum at 24″ o.c., 5/8″ Firecode core each side, Type S screws 8″ o.c. - U411, U412 or U419 (2-hr, steel): panels vertical or horizontal, **joints of face layer…

Alabama Metal Stud and Drywall Contractor

Key Concepts

Fasteners — sizes and types - Double-layer application: 1″ Type S screws for the base layer, 1-5/8″ Type S screws for the face layer (Gypsum Construction Handbook, Backerboard Installation, Board application section). Base layer fastened 16″ o.c.; face layer centered over base-layer joints, 12″ o.c. - Resilient channels to wood studs: 1-1/4″ Type W screws through the flanges; nails not recommended (GCH Ch. 2, Resilient Channel Partitions). - Steel runners to wood framing: 1-1/4″ Type S oval head screws or 8d nails (GCH Ch. 2, Runner Installation). Runners to concrete/masonry: stub nails or power-driven fasteners. - Steel studs to runners, 25- and 22-gauge: 3/8″ Type S pan head screw (GCH Ch. 1, Selector Guide for Screws). - Drywall suspension system: No. 6 Type S bugle head screws, 8″ o.c. at periphery, 12″ o.c. in the field (GCH Ch. 2, Gypsum Panel Installation). - Staples (base layer to wood, double-layer): 16-gauge flattened galvanized wire, 7/16″ crown, divergent points, minimum 5/8″ penetration (GCH Cladding, Staple Application). - Wood framing: Type W or Type S screws must penetrate wood not less than 5/8 inch (IRC R702.3.5.1). Cold-formed steel: minimum No. 6 screws; steel less than 0.033″ thick requires Type S penetrating not less than 3/8 inch (IRC R702.3.5.1). - Fasteners "shall be applied in such a manner as not to fracture the face paper with the fastener head" (IBC 2508.3.1).

Alabama Metal Stud and Drywall Contractor

Key Concepts

Finishing-level definitions (Finishing Drywall Systems, Chapter 5 — Finishing-Level Definitions)

• Level 0 — Unfinished. No taping, finishing or corner beads required. Used in temporary construction or wherever the final decoration has not been determined. (Level 0, p. 161)
• Level 1 and Level 2 — Tool marks and ridges are acceptable at both levels. Beginning at Level 3, all joint compound must be smooth and free of tool marks and ridges. (Level 1 and Level 2)
• Level 3 — One additional coat of joint compound over all joints and interior angles beyond the embedding coat; two separate coats over fastener heads and accessories. (Level 3, pp. 161–162)
• Level 4 — Two separate coats over flat joints, one separate coat over interior angles, and three separate coats over fastener heads and accessories, beyond the embedding coat. Gloss, semigloss and enamel paints are not recommended over Level 4. (Level 4, p. 162)
• Level 5 — Highest quality finish; a thin skim coat of joint compound is trowel-applied over the entire surface after all joint, angle and fastener treatments. Minimizes joint photographing; required for gloss, semigloss and enamel paints. (Level 5)

Joint treatment sequence

Alabama Metal Stud and Drywall Contractor · 6 questions (15% of exam)

Key Concepts

Curved surfaces and arches

• When facing arches with gypsum panels, the back paper must be scored or cut through at 1-inch intervals so the panel is flexible enough to conform to the curved arch framing. (Gypsum Construction Handbook, Arches section, Book Page 138–139)
• For wet bending, evenly spray water on the surface that will be in tension when the board is hung. Stack boards with wet surfaces facing each other, cover the stack with a plastic (polyethylene) sheet, and allow the boards to set at least 1 hour before installation. When the board dries thoroughly it regains its original hardness. (Gypsum Construction Handbook, Cladding — Curved Surfaces, Installation, Book Page 137)
• Curved-wall framing: cut one leg and web of the top and bottom steel runners at 2-inch intervals for the length of the arc, leaving 12 inches of uncut runner at each end; bend to a uniform curve (90° max. arc). Support the cut leg with a 1″ × 25-ga. steel strip clinched to the inside of the leg. For wood studs, use a 3-1/2″ steel runner. On tangents, place studs 6″ o.c., leaving the last stud free-standing. (Handbook, Curved Surfaces — Framing, Book Page 137)
• Panel selection: cut board so one unbroken panel covers the curved surface plus 12-inch tangents at each end; the outside panel must be longer than inside panels. Cut-outs for electrical boxes are not recommended in curved surfaces unless made after the boards are installed and thoroughly dry. (Handbook, Panel Preparation, Book Page 137)
• Application: apply panels horizontally, wrapped edge perpendicular to studs. On the…

Alabama Metal Stud and Drywall Contractor

Key Concepts

Fall protection thresholds - Each employee on a walking/working surface with an unprotected side or edge 6 feet (1.8 m) or more above a lower level must be protected by guardrail systems, safety net systems, or personal fall arrest systems — 29 CFR 1926, §1926.501(b)(1). - Guardrail top rails: top edge height 42 inches (1.1 m) plus or minus 3 inches (8 cm) above the walking/working level — §1926.502(b)(1). - Personal fall arrest systems must be rigged so an employee can neither free fall more than 6 feet (1.8 m) nor contact any lower level — §1926.502(d)(16)(iii). - Anchorages for personal fall arrest equipment must be independent of any anchorage used to support or suspend platforms and capable of supporting at least 5,000 pounds (22.2 kN) per employee attached, or be designed, installed and used as part of a complete system maintaining a safety factor of at least two under the supervision of a qualified person — §1926.502(d)(15). - Safety nets are required where workplaces are more than 25 feet above the ground or water surface (or other surfaces) and use of ladders, scaffolds, catch platforms, temporary floors, safety lines or safety belts is impractical — §1926.105(a). - Covers in roadways and vehicular aisles must support, without failure, at least twice the maximum axle load of the largest vehicle expected to cross the cover — §1926.502(i)(1).