Louisiana Carpentry

Key Concepts

Fall protection trigger heights - Residential construction: fall protection required at 6 ft (exam verified answer). - Scaffolds: each employee on a scaffold more than 10 feet (3.1 m) above a lower level must be protected from falling — §1926.451(g)(1).

Personal fall arrest systems - 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). - A lifeline must be secured to a structural member above the worker capable of supporting a minimum deadweight of 5,400 lbs.; a lifeline should be only long enough to ensure a worker can fall no more than 6' (Carpentry and Building Construction, Ladders, Scaffolds & Other Support, p. 209).

Guardrail systems - Top edge height of top rails: 42 inches (1.1 m) plus or minus 3 inches (8 cm) above the walking/working level (i.e., 39–45") — §1926.502(b)(1). - Textbook rule for scaffolds manufactured after January 1, 2000: guardrail placed between 38" and 45" above the scaffold planks, with a mid-rail about halfway between guardrail and planks (p. 205).

Key Concepts

Building envelope and where to insulate - All walls, ceilings, roofs and floors that separate heated from unheated spaces should be insulated; this continuous layer is the building envelope. Everything inside it is heated/cooled; everything outside is exposed to outdoor temperatures. (Carpentry and Building Construction, Section 31.1 — Where to Insulate) - In a one-and-a-half-story house, second-floor knee walls are treated just as if they were exterior walls, because they separate heated from unheated space. (Section 31.1 — Where to Insulate (Walls)) - In floor systems over an unheated crawl space, the vapor retarder faces toward the subflooring above — the warm side. (Section 31.1 — Where to Insulate (Floor Systems))

Vapor retarders - Kraft paper facing on batts serves as the vapor retarder; its continuous side tabs allow stapling to studs or joists. Unfaced ("friction-fit") batts are pressed into cavities, and 4-mil thick plastic film must be stapled over the walls to serve as the vapor retarder. (Section 31.1) - Under a concrete floor slab: a 6-mil (0.006 inch; 0.15 mm) polyethylene vapor retarder with joints lapped not less than 6 inches (152 mm) shall be placed between the base course or subgrade and the slab,…

Key Concepts

Window operating types. A casement window has a side‑hinged sash that swings inward or outward; its advantage over the double‑hung type is that the entire window area can be opened for ventilation (Windows & Skylights, Types of Windows).

Window parts. A muntin is a short vertical or horizontal piece that holds a pane of glass; historically used to hold small panes together into one window. A mullion strip is a vertical piece separating combined window units (Windows & Skylights, Double‑Hung Windows).

Egress and light/ventilation. Egress windows must have an unblocked open area not less than 5.7 sq. ft., except windows on the grade floor, which require not less than 5.0 sq. ft. Openable window area for ventilation must be not less than 4 percent of the floor area, unless mechanical air conditioning and ventilation are provided; the 8 percent figure applies to total window glass area for natural light, not ventilation (Windows & Skylights, Design Requirements).

Energy performance. U‑values are like R‑values reversed: a lower U‑value means less heat loss or gain and greater insulating performance. The NFRC uses U‑values along with other metrics to rate window energy efficiency (Windows & Skylights, Energy Efficiency – Ratings).

Key Concepts

Floor framing - Joist ends: not less than 1½ in. bearing on wood or metal, not less than 3 in. on masonry (IBC 2308.4.2.2). Wood girders should bear at least 4 in. on masonry walls (Carpentry & Building Construction 15.1, p. 401). - Joists framing from opposite sides of a beam, girder or partition: lapped not less than 3 in., or tied in an approved manner (IBC 2308.4.2.3). - Bored holes in joists: not within 2 in. of top or bottom; diameter shall not exceed one-third the joist depth (IBC 2308.4.2.4). - Girders for single-story construction or supporting a single floor: not less than 4 in. × 6 in. for spans 6 ft or less, provided girders are spaced not more than 8 ft on center (IBC 2308.4.1). - Tail joists over 12 ft: supported at the header by framing anchors or ledger strips not less than 2 in. × 2 in. (IBC 2308.4.4). - Anchor bolts for sill plates: embedded not less than 7 in. into concrete (IBC 1905.1.8); spaced no more than 6 ft on center with a bolt within 12 in. of each end of every plate (15.2, p. 402). - Doubled joists under…

Key Concepts

Stair codes (Carpentry and Building Construction, Ch. 25, Sec. 25.1, "Stair Codes" — code dimensions are from the 2006 IRC) - Headroom: minimum 6'-8" on stairs and landings, measured from the outermost edge of the nosing to the ceiling surface directly overhead; main stairways generally have 7'-4" to 7'-7". - Risers and treads: maximum riser 7¾", minimum tread depth 10". Safety research indicates the ideal riser is 7" and the ideal tread 11" (Ch. 25, p. 731). - Uniformity: variation of no more than ⅜" between the maximum and minimum riser heights, and no more than ⅜" between the deepest and shallowest tread (p. 731). - Rule of thumb: one riser plus one tread should total between 17 and 18 inches. - Winders: at least 10" wide at a point measured 12" away from the wall; no part of a winder less than 6" wide. - Width: minimum stairway width 36" between finished walls (42" eases moving furniture). With two handrails, minimum distance between them is 25"; with one handrail, minimum clear width to the opposite wall is 31½". - Handrails: 34" to 38" high, measured vertically from the upper edge of the nosing to the top…

Key Concepts

Panel types and selection - Type-X fire-code drywall is 5/8″ thick and contains glass fibers that prevent it from crumbling in extreme heat. Type-C is even more fire resistant and contains vermiculite. (Carpentry and Building Construction, Ch. 32, Fire-Code Drywall section) - The long edges of standard panels are tapered so joints can be filled with joint compound and smoothed flush. (Ch. 32, Standard Drywall section) - Glass-mat gypsum board ("paperless drywall") has fiberglass instead of paper on both faces and is an approved backing in shower stalls and tub/shower surrounds; starting with the 2006 IRC green board is no longer allowed there except on ceiling surfaces. Cement board and fiber-cement backer board are the other approved materials. (Ch. 32, Moisture-Resistant Drywall, Page 917) - Water-resistant gypsum backing board shall not be used over a vapor retarder in shower or bathtub compartments, nor where there will be direct exposure to water or in areas subject to continuous high humidity. It is permitted as a base for tile in water closet compartment walls. (2021 IBC §2509.3; §2509.2) - 3/8″ panels are designed for framing centers up to 16″; 1/2″ and 5/8″ panels up to 24″. (Gypsum Construction Handbook…

Key Concepts

Purpose and sequence of siding - Siding is the exterior wall covering of a house; its purpose is to shed rain and protect the structural portions of walls. Installation normally begins after windows and doors are in place and after the roofing has been installed (Carpentry and Building Construction, Ch. 23 — Siding Basics, p. 658). - Siding materials include solid wood, vinyl, plywood, steel, aluminum, stucco, and fiber cement; brick is covered in Chapter 24 (Ch. 23, p. 658). - Code terminology: the IRC refers to siding as "exterior wall covering," providing weather resistance to the "exterior wall envelope" (Ch. 23 — Builder's Tip: Code Terminology, p. 658).

Moisture protection - No. 15 (15 lb.) building paper is the minimum weight required by code beneath siding. No. 30 is heavier but is not the required minimum (Ch. 23 — Preventing Moisture Problems / Building Paper). - Building paper laps: vertical joints must lap at least 6 inches; horizontal courses must lap at least 2 inches over previously applied strips (Ch. 23 — Building Paper). - Housewrap should not be used beneath stucco siding, because the stucco can bond to the housewrap in a way that causes…