Louisiana Building Construction

Key Concepts

Layout from a reference line. A building planned parallel to an existing street or marked property line can use that line as a reference line, making it possible to stake out the site without a surveying instrument (Carpentry & Building Construction, Ch. 9 — Basic Techniques / Measuring From a Reference Line). The purpose of site layout is to position the house correctly on the lot per building and zoning codes (Ch. 9 — Purpose of Site Layout).

Instruments. A builder's level (dumpy level) is the least expensive instrument, accurate to ±¼" at 75'; an automatic level is usually ±¼" at 100', some to ±1/16" at 200' (Ch. 9 — Types of Instruments / Levels). A transit is classified by the smallest increment readable on its vernier scale (five-minute, one-minute, twenty-second). A theodolite is a transit that…

Key Concepts

Cement and hydration - Hydration is the chemical reaction that occurs when water combines with cement; it generates heat and causes concrete to harden — concrete does not "dry out" (Carpentry and Building Construction, Ch. 8 — Hydration section). - No more than 5 percent gypsum is added to clinker before grinding into cement powder (C&BC, Ch. 8 — Portland Cement section). - Types (C&BC, Table 8-1; Modern Masonry, Ch. 18, p. 383; DCCM 17th ed., Ch. 2): Type I general purpose; Type II moderate; Type II(MH) generates heat slower by limiting the heat index (C₃S + 4.75 C₃A) to a maximum of 100 (p. 30); Type III high-early-strength, used where forms must be stripped or concrete put in service quickly; Type IV low heat, for massive structures such as dams; Type V severe sulfate exposure, C₃A…

Key Concepts

Concrete and admixtures - Concrete exposed to freezing and thawing should be air entrained with a minimum total air content of 5%. A mix at 2% or less gains no benefit from the admixture; over 7% can reduce strength (Modern Masonry, p. 385). - Recommended air contents for severe freeze-thaw exposure range from 4-1/2% to 7-1/2% depending on maximum aggregate size (6% for 3/4 in. aggregate), with a field tolerance of ±1-1/2%. "Too much air can lower concrete strength and make it less durable" (Table 2.2). - Largest coarse aggregate: never greater than one-fifth the thickness of a finished wall section, one-third a slab thickness, or three-fourths the narrowest space the concrete passes through (Modern Masonry, p. 384). - Concrete that stiffens before initial set may be remixed without adding water; retempering with water reduces quality (*Modern…

Louisiana Building Construction

Key Concepts

Joist series and designations (SJI Technical Digest No. 9, Chapter 1 – Products) - Standard SJI products: K-Series, LH-Series, DLH-Series, Joist Girders, and CJ-Series composite joists. Scissor, barrel, bowstring, and gable joists are non-standard products. - K-Series: depths 10"–30"; chords and web members normally comprised of hot-rolled angles or cold-formed sections. Designation 18K7 = 18" nominal depth, K series, 7 = chord number designation. - LH-Series: depths 18"–48", spans up to 96 feet. DLH-Series: depths 52"–120", spans up to 240 feet. Joist girders: depths 20"–120", spans up to 120 feet. - Joist girder designation 36G9N6K: 36" nominal depth, G = joist girder, 9N = 9 joist spacings, 6K = 6 kips unfactored panel point load (ASD). - Composite 30CJ2188/1168/420: 2188 = total factored composite design load (plf), **1168 = total factored composite live load…

Building Construction

Key Concepts

Roof framing terminology - A ridge board (ridge) is the horizontal piece that connects the upper ends of the rafters and extends the full length of the house; a collar tie is a horizontal tie connecting opposite pairs of rafters (Carpentry and Building Construction, p. 468). - Slope = ratio of rise to run; pitch = ratio of rise to span. They are not interchangeable — slope is the term most suited to roof framing (p. 470). - The unit run of a common rafter is always 12"; the unit run for a rafter at 45° to the ridge is 17" (p. 470). - On a hip roof framing plan, 45° lines drawn from each corner to the centerline establish the location of the hip rafters; the 45° angle gives each roof surface the same…

Key Concepts

Roof coverings and slope minimums - Wood shakes: slopes not less than 4:12 (IBC 1507.9.2). Wood shingles minimum 3:12; clay/concrete tile 2½:12. - Asphalt shingles on slopes from 2:12 up to 4:12 require double underlayment application (IBC 1507.2.2, per Section 1507.2.8). - Built-up roofs: design slope not less than ¼:12 (2 percent); coal-tar built-up roofs ⅛:12 (1 percent) (IBC 1507.10.1). - SPF roofing: liquid-applied protective coating applied not less than 2 hours nor more than 72 hours after foam application (IBC 1507.14.3). - Wood shingles on spaced sheathing: boards not less than 1 × 4 nominal, spaced on centers equal to the weather exposure (IBC 1507.8.1).

Key Concepts

Window design requirements (Chapter 20 — Design Requirements) - Total area of window glass in a room: not less than 8 percent of the floor area (natural light). - Total window area that can be opened for ventilation: not less than 4 percent of the floor area, unless mechanical air conditioning and ventilation are provided. - Bathrooms: no less than 3 sq. ft. of glazing, unless ventilated with a fan.

Bedroom egress windows (Chapter 20 — Design Requirements). Every bedroom must have at least one window (or exterior door) suitable for egress, with: - Sill height no more than 44" above the floor - Height of opening no less than 24" - Width of opening no less than 20" - Unblocked open area no less than 5.7 sq. ft., except grade-floor openings, which must be **no less…

Key Concepts

Drywall materials and fire-code types - Drywall is a noncombustible gypsum core covered with paper — smooth face paper on the front, rough liner paper on the back. It is strongest in its long dimension and is dimensionally stable (Carpentry & Building Construction, Ch. 32, Drywall Basics). - Type-X fire-code drywall is 5/8" thick and contains glass fibers that prevent crumbling in extreme heat. It is code-required on the outer surface of walls separating an attached garage from the house, and on garage ceilings where the garage is beneath a habitable room. Type-C is more fire resistant than Type-X and contains vermiculite (Ch. 32, Fire-Code Drywall). - Most common panel thickness is ½"; panels are commonly 4' × 8', also 9', 10', 12', 14'. Long edges are tapered so joints can be filled and smoothed (Ch. 32).…

Key Concepts

Employer/employee duties. Under OSHA regulations the employer must keep the workplace free from recognized hazards likely to cause death or serious physical harm, provide training for all hazardous work and PPE use, and comply with OSHA standards including record-keeping and accident reporting; employees must comply with OSHA regulations and other applicable standards (Carpentry and Building Construction, Construction Safety & Health, Job Site Safety). A repeat serious violation fine may exceed $150,000. A competent person is one capable of identifying existing and predictable hazards in the surroundings or working conditions which are unsanitary, hazardous, or dangerous, and who has authorization to take prompt corrective measures (§1926.32(f); §1926.650(b)). PPE used to comply with Part 1926 must be provided by the employer at no cost to employees, with limited exceptions (§1926.95(d)). Manufacturers must supply Material Safety Data Sheets (MSDS) listing…

Key Concepts

Occupancy classification. Group A-2 covers assembly uses intended for food and/or drink consumption — restaurants, cafeterias, nightclubs, banquet halls, taverns and bars (IBC 2018, Section 303.3, Page 46).

Types of construction. Type III construction is that in which the exterior walls are of noncombustible materials and the interior building elements are of any material permitted by the code (IBC 2018, Section 602.3, Page 119).

Fire-resistance ratings tied to construction type. - Fire walls separating Group F-2, S-2, R-3 and R-4 require a minimum 2-hour rating; Groups A, B, E, H-4, I, R-1, R-2 and U require 3 hours (2 hours permitted in Type II or V); H-1 and H-2 require 4 hours (Table 706.4, Page 131). - Fire barriers/fire walls/horizontal assemblies separating fire areas of Group U require not less than 1 hour — the lowest in…