Modern Masonry: Brick, Block, Stone 9e, Textbook Page 247 (263 of 543)

Copyright Goodheart-Willcox Co., Inc. Chapter 12 Laying Brick 247 15. Lay the wall to a height of eight courses and then embed metal Z-shaped ties as previously instructed. The ties should be offset from the ties on the second course. 16. Attach wires at each end of a piece of wood 1″ × 2″ × 4′ long. The board is used to catch any mortar droppings and to flatten any mortar squeezed out inside the cavity. 17. Complete the cavity wall to a height of twelve courses using the wood piece to catch mortar. Check the wall to be sure that it is square and plumb. Remove any mortar splatter on the outside wall and clean with a bricklayer’s brush. 18. When the mortar has reached thumbprint hard, finish the joints with a convex jointer. Remove any tailings that are produced from tooling. 12.3.9 Constructing a Single Wythe Brick Bearing Wall Single wythe concrete masonry construction is a cost effective and durable form of masonry construction. Single wythe brick bearing walls are sometimes used in one- and two-story home designs and may also be used in commercial construction. In this type of system, the brick masonry serves as both the structural system and the exterior facing. See Figure 12-61. A wood, steel, or masonry backing system is not necessary. Structural Design Design considerations for single wythe brick loadbear- ing walls include minimum loads to be resisted by the structural system, minimum thermal performance requirements, necessary fire resistance of the wall system, and resistance to moisture penetration. These specifications are covered by the model building codes. Determining the design loads (vertical and horizon- tal) is generally the first step in the design of a struc- tural system. Vertical loads include loads from the 8 7 Z drip tie Elevation NOTE: Ties at 16uni2033 O.C. vertical and horizontal staggered. First course 1 3 4 6 2 5 Weep holes Weep holes Second course Goodheart-Willcox Publisher Figure 12-60. Procedure for laying a 10″ cavity wall with metal ties. 6" masonry wall Flashing Weep holes 2uni2032 0° O.C. Grade 6° Slab construction Perimeter insulation Compacted sand Vapor seal Floor slab Base trim Furring anchor Interior finish Furring Goodheart-Willcox Publisher Figure 12-61. Detail of a 6″ exterior loadbearing single wythe wall.

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Copyright Goodheart-Willcox Co., Inc. Chapter 12 Laying Brick 247 15. Lay the wall to a height of eight courses and then embed metal Z-shaped ties as previously instructed. The ties should be offset from the ties on the second course. 16. Attach wires at each end of a piece of wood 1″ × 2″ × 4′ long. The board is used to catch any mortar droppings and to flatten any mortar squeezed out inside the cavity. 17. Complete the cavity wall to a height of twelve courses using the wood piece to catch mortar. Check the wall to be sure that it is square and plumb. Remove any mortar splatter on the outside wall and clean with a bricklayer’s brush. 18. When the mortar has reached thumbprint hard, finish the joints with a convex jointer. Remove any tailings that are produced from tooling. 12.3.9 Constructing a Single Wythe Brick Bearing Wall Single wythe concrete masonry construction is a cost effective and durable form of masonry construction. Single wythe brick bearing walls are sometimes used in one- and two-story home designs and may also be used in commercial construction. In this type of system, the brick masonry serves as both the structural system and the exterior facing. See Figure 12-61. A wood, steel, or masonry backing system is not necessary. Structural Design Design considerations for single wythe brick loadbear- ing walls include minimum loads to be resisted by the structural system, minimum thermal performance requirements, necessary fire resistance of the wall system, and resistance to moisture penetration. These specifications are covered by the model building codes. Determining the design loads (vertical and horizon- tal) is generally the first step in the design of a struc- tural system. Vertical loads include loads from the 8 7 Z drip tie Elevation NOTE: Ties at 16uni2033 O.C. vertical and horizontal staggered. First course 1 3 4 6 2 5 Weep holes Weep holes Second course Goodheart-Willcox Publisher Figure 12-60. Procedure for laying a 10″ cavity wall with metal ties. 6" masonry wall Flashing Weep holes 2uni2032 0° O.C. Grade 6° Slab construction Perimeter insulation Compacted sand Vapor seal Floor slab Base trim Furring anchor Interior finish Furring Goodheart-Willcox Publisher Figure 12-61. Detail of a 6″ exterior loadbearing single wythe wall.

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Copyright Goodheart-Willcox Co., Inc. 246 Section 4 Techniques ■ ■ Flashing. Flashing materials should be stored where they will not be punctured or damaged. Plastic and asphalt-coated flashing materials should not be stored in areas exposed to sunlight. Sunlight causes them to become brittle. ■ ■ Insulation. Rigid insulation should be stored where it is not exposed to sunlight. Sunlight over time can cause rigid insulation to deteriorate. If rigid insulation is stored outside, it should be off the ground, covered, weighted down, and protected because the lightweight panels are easily damaged. Protection of Walls Masonry walls that are exposed to heavy rain dur- ing construction can become so saturated with water that they may require weeks or even months to dry out. This increases the likelihood of soluble salts going into solution, which may contribute to efflorescence or contaminate other elements of the structure, such as concrete, plaster, and trim. All walls should be kept dry by covering the top of the wall with a strong, water-resistant membrane at the end of each working day. The membrane should overhang the wall by at least 24″ on each side and be secured against wind. The cavity wall should remain covered until it is completed and protected by other materials. It is important to keep masonry from freezing while the mortar is setting or when new material is to be placed on previously laid units. Mortar joints are sus- ceptible to freezing. If freezing occurs, the bonding between the units is affected and damage may occur. There are many ways to protect newly laid masonry when freezing temperatures are forecasted. Using insu- lated blankets or erecting shelters are two methods to keep mortar from freezing. To cover masonry, drape blankets over the newly laid units. Place bricks or 2 × 4 lumber as weight on top of the blankets to reduce the chances that wind will move the blankets. Where one blanket ends and another begins, overlap the seams and place the weight, such as a number of bricks or a concrete block, against the blankets to secure them against the wall. 12.3.8 Laying a 10″ Brick Cavity Wall with Metal Ties A typical 10″ brick cavity wall with a corner is shown in Figure 12-60. Use the standard planning and layout procedure in laying out this practice wall. Flashing has purposely been omitted in this exercise. Be especially careful not to drop mortar into the cavity. P R O C E D U R E Laying a 10″ Brick Cavity Wall with Metal Ties 1. Locate the outside wall edges and snap a chalk line to preserve the location. 2. Lay out the brick dry to determine proper spacing and any layout problems. Locate the inside line for the backing wythe such that it is 10″ away from the outside wall edge. This should form a 2″ cavity between the wythes. 3. Lay the inside bed course beginning at brick #1 and continuing to brick #2. Work from both ends toward the middle. Use a full bed joint, checking the bricks to be sure they are plumb and level. Use the chalk line to ensure a straight wall. 4. Continue the outside wythe by laying brick #6 and the closure between brick #6 and brick #1. Level, align, and plumb this part of the wall. Check to be sure the corner is square. 5. Bricks #3, #4, and #5 are three-quarter brick. Cut them. 6. Lay bed bricks #3, #4, and #5 in the position shown in Figure 12-60. Level and plumb the brick. Be sure the outside edge of bricks #3 and #4 are 10″ from the inside face. Check the position of bricks #2 and #5 to be sure they are square. 7. Lay the brick between bed bricks #4 and #5 and finish the leg from bed brick #3. Level, align, and plumb these sections of the wall. The first course is now complete and should be square at the corners and 10″ wide throughout. 8. If you did not use empty head joints for the four weep holes shown in the elevation, open those joints or insert tubing or wicking at the weep hole locations. 9. Cut three (3) three-quarter bricks for the second course and lay the mortar bed for the second course. Bevel the mortar bed to avoid dropping mortar into the cavity. 10. Lay three-quarter brick #7 at the right end of the wall over bed bricks #2 and #5. 11. Lay second course brick #8 at the other end of the wall and complete the wythe between them. 12. Complete the second course following the procedure established for the first course. Plaster back any mortar that is squeezed out of the inside bed joints. Keep the cavity clean. 13. Locate the four metal Z-shaped ties as shown in the second course plan. Embed the ties in the mortar bed being sure that the drip on the metal ties points downward if your ties are of this design. 14. Build corner leads six courses high on each end of the wall so a mason’s line can be used to aid in the construction of the wall.

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Copyright Goodheart-Willcox Co., Inc. 248 Section 4 Techniques weight of building materials and occupants. Lateral loads include wind, soil, and seismic events. In most regions of the United States, only vertical loads and wind loads are a major concern, but in some areas, seis- mic loads may control the structural design. Addition- ally, severe wind loads, as in hurricane prone areas, may dictate the structural design. The size of a building’s structural member is determined by model building codes and the structural loads. Masons are required to familiarize themselves with the International Building Code (IBC) and the Inter- national Residential Code (IRC), but other codes may also be used in the design and construction process of a facility. When questions arise related to one of the codes, a local building official can be contacted to clar- ify construction process rules and regulations. Location of Interior Work Because there is no cavity within the exterior wall to place plumbing, heating/air-conditioning, and elec- trical systems, the systems must be located between the furring strips, in the floor or ceiling, or in interior frame walls. The type of foundation and floor system used influences the location of interior systems. In structures with basements or crawl spaces, mechanical systems can be located between the floor joists. In slab type structures, it is easier to route mechanical systems through the ceiling or attic space. Structural Materials According to BIA Technical Note 26—Single Wythe Brick Bearing Walls, selection of masonry materials for single wythe brick bearing wall systems should consider the structural, energy, and reinforcement performance requirements. The following are some considerations: ■ ■ Brick. The brick masonry units used in a single wythe bearing wall are solid (ASTM C216) or hollow (ASTM C652). Solid bricks are commonly manufactured in nominal widths of 3″, 4″, and 6″. Code Note Minimal Nominal Wall Thickness The International Residential Code (IRC) specifies an 8″ minimum nominal wall thickness for loadbearing masonry structures over one story in height. A nominal 6″ wall is permitted for a single-story home or garage if the wall height does not exceed 9′ and the gable height does not exceed 15′. Minimum wall thickness requirements influence the type and size of brick and block selections. Other model building codes have similar restrictions, so it is important to research the local codes. Hollow bricks are available in nominal widths of 4″, 5″, 6″, and 8″. Nominal 5″ and 6″ wide hollow bricks are most commonly used to build this type of wall for residential purposes. The cells in most hollow bricks are made to accommodate vertical reinforcement and grout. ■ ■ Mortar. Portland cement-lime mortars with an air content of less than 12% are recommended for their superior bond strength and resistance to water penetration. Masonry cements are prohibited by some codes and all type N mortars are prohibited in seismic performance categories D and E (formerly zones 3 and 4). Type S, M, or N mortar may be generally used in loadbearing brick masonry. Type S is recommended for use in reinforced brick bearing walls. ■ ■ Grout. Steel reinforcement is bonded to the surrounding brick masonry using grout. Grout may be made using fine or coarse aggregate, but fine aggregate is generally used because it is easier to fill smaller cells. Grout should meet ASTM C476. The water/cement ratio of grout should have a slump of 8″ to 11″. It must be fluid enough to fill voids, but not separate into its constituent parts. ■ ■ Reinforcement. Lateral loads must be resisted through the use of vertical steel reinforcement or other means. See Figure 12-62. The Masonry Standards Joint Committee (MSJC) Code limits the maximum size of reinforcement used in masonry to a No. 11 reinforcing bar. As a rule-of- thumb, the maximum bar size should not exceed the nominal thickness of the wall in inches to ensure proper development of the reinforcement. For example, a maximum reinforcing bar size No. 6 is recommended for nominal 6″ walls. Vertical reinforcement in grouted cell Brick Industry Association Figure 12-62. Vertical reinforcing used to resist lateral loads in a single wythe wall.

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Page 2Section 1 Succeeding on the Job click to expand contents

Page 24Section 2 Introduction to Masonry click to expand contents

Page 110Section 3 Materials click to expand contents

Page 218Section 4 Techniques click to expand contents

Page 308Section 5 Construction Details click to expand contents

Page 380Section 6 Concrete click to expand contents

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