Louisiana Masonry, Brick and Stone

Key Concepts

Construction drawings and the Alphabet of Lines (Chapter 5, Pages 68–69) - Object lines are heavy lines showing visible features; hidden lines are medium-weight lines for edges not visible in a view; center lines are thin lines marking the center of symmetrical objects; extension lines are thin and extend past the dimension line about 1/16". - Long break lines are thin, extend past the object about 1/16" on either side, and carry an S-shaped symbol in the center. Short break lines are heavy with a curvy, irregular shape (Page 69). - Cutting plane lines are heavy and are generally attached to a section symbol identifying the detail drawing. - Section (crosshatch) lines are very thin, usually drawn at 45° and spaced about 1/16" to 1/8" apart (Page 69).

Key Concepts

Brick classification and grades - A solid masonry unit is one whose cross-sectional area in every plane parallel to the bearing surface is 75% or more of its gross cross-sectional area measured in the same plane. Cored brick remain solid units if coring is under 25%. A unit with less than 75% solid material is a hollow masonry unit. (Modern Masonry 9th ed., p. 123) - Grade SW (Severe Weathering) building brick is highly resistant to frost action — use in foundation courses and retaining walls. Grade MW is for moderate exposure; Grade NW is for interior backup. (p. 116) - Paving brick: Type F pavers set in a sand base with sand-filled joints must be at least 2 5/8" thick; Type R pavers (mortar or asphalt base over compacted, drained subbase) need only 2 1/4". (p. 116) - Structural clay loadbearing wall tile: Grade LB is for areas not exposed to…

Louisiana Masonry, Brick and Stone Exam | 11 questions (18%)

Key Concepts

Mortar materials - Only Type S hydrated lime is recommended for masonry mortar because unhydrated oxides and plasticity are controlled, improving bond to the units; these are not controlled in Type N (Modern Masonry 9th ed., §10.1.1 / p. 187). - Portland cement Types I, II and III are recommended for mortar. Types IA, IIA and IIIA are not recommended because air entrainment reduces the bond between mortar and masonry units or reinforcement (p. 187). - ASTM standards: C150 Portland cement, C207 hydrated lime, C5 quicklime, C91 masonry cement, C144 aggregate (sand) for mortar, C404 aggregates for grout (§10.1.2 / Fig. 10-1). - Water must be clean and free of harmful amounts of acids, alkalis or organic materials per ASTM C270; potability is not a concern (§10.1.3).

Key Concepts

Wall ties (IRC Code Note — Modern Masonry, Ch. 11, p. 204) - Ends of wall ties are embedded in mortar joints with a minimum 5/8" (15.9 mm) mortar coverage from the exposed face. - Ties are not to be bent after being embedded in grout or mortar. - Solid masonry units, solid grouted hollow units, or hollow units in anchored masonry veneer: embed at least 1 1/2" (38 mm) in the mortar bed. - Hollow masonry units in other than anchored veneer: engage outer face shells at least 1/2" (13 mm).

Unit ties (p. 205) — three types: rectangular, Z, corrugated. Rectangular and Z ties are generally cold-drawn steel wire to ASTM A82 or copper-clad wire to ASTM B227; stainless is available for highly corrosive applications. Corrugated ties are usually sheet steel, grade D (also copper and stainless).

Key Concepts

Classification by formation. Stone is divided into three categories based on the process of formation: igneous (volcanic), sedimentary, and metamorphic (Modern Masonry 9th ed., Ch. 9, p. 174). A given sample may result from more than one process.

• Igneous — classified by texture, mineral content, and origin; all comes from magma. Composed primarily of light minerals (quartz and potash feldspar) it is called acidic — light in color and weight. With a greater degree of ferro-magnesian minerals it is basic — darker and heavier (§9.1.1). Types: granite, traprock.
• Sedimentary — formed in layers; sandstone and limestone. Limestone weathers rapidly in humid climates but very slowly where it is dry (§9.1.2). Indiana (Bedford) limestone is a freestone with a grain running horizontally; set with grain horizontal it is on its natural bed, set with grain vertical it is on edge.
• Metamorphic — formed through reconstitution due to great heat and…

Key Concepts

Trowel patterns (Ch. 3, Sec. 3.1.1 Trowels). Philadelphia pattern trowels allow more mortar to be placed on the blade, so they are best suited for applying mortar to block. London pattern trowels have the standard blade type for laying brick. Wide London pattern trowels have a rounded heel, which places the mortar farther forward on the blade compared to the Philadelphia pattern; a Wide London can be used for brick or block. The narrow end of the blade is the "point," the wide end nearest the handle is the "heel," and the shank connects blade to handle. Wood handles usually have a ferrule (metal band) that adds strength and prevents splitting. Trowels are available in lengths from about 3" to 13".

Key Concepts

Diagnose before repointing. The root cause of deterioration — leaking roofs or gutters, differential settlement, capillary action causing rising damp, or extreme weather exposure — should always be dealt with prior to beginning work (Preservation Brief 2, Identifying the Problem Before Repointing, p. 2).

Mortar match criteria (Preservation Brief 2, Finding an Appropriate Mortar Match, pp. 2–3): new mortar must match the historic mortar in color, texture and tooling; the sand must match the historic sand; the new mortar must have greater vapor permeability and be softer (compressive strength) than the masonry units; and must be as vapor permeable and as soft or softer than the historic mortar. The most useful product of laboratory analysis is identification of sand by gradation and color.

Louisiana — Masonry, Brick and Stone | 6 questions (10% of exam)

Key Concepts

Minimum reinforcement in reinforced masonry walls Reinforced masonry walls shall be reinforced with an area of steel not less than 0.002 times the cross-sectional area of the wall, with not more than two-thirds of that area used in either direction. Maximum spacing of principal reinforcement shall not exceed 48 in. (Modern Masonry 9th ed., Page 338)

Columns (MSJC Code and Specifications) Minimum of four reinforcing bars; reinforcement area at least 0.0025 but not more than 0.04 times the column's net cross-sectional area; minimum nominal column dimension is 8"; ratio of height to least lateral dimension must not exceed 25. (Modern Masonry 9th ed., Page 319)

Key Concepts

Fall protection trigger heights (Subpart M vs. Subpart L) - 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 — §1926.501(b)(1). The same 6-foot trigger applies to residential construction — §1926.501(b)(13). - Each employee on a scaffold more than 10 feet (3.1 m) above a lower level shall be protected from falling to that lower level — §1926.451(g)(1). - Modern Masonry (9th ed.), Ch. 4, §4.2.6: OSHA requires construction workers be protected at levels 6' and above for most construction activities; falls are the leading cause of construction deaths, about 40% (roughly 400 of nearly 1,000 annual deaths).