2. 14
CHAPTER
Wall Systems

3. Objectives Describe different types of masonry wall systems.
Explain the use of ties, flashing, weep holes, lintels, sills, jambs, and expansion joints in masonry wall systems.
Explain the effects of moisture condensation in masonry walls and the methods used to resist condensation.

4. Objectives (Cont.)
Describe construction procedures for thin brick veneer, including thin bed set, thick bed set, and precast panels.
Explain the design, function, and construction of arches.
Describe the joints used for movement in masonry.
Understand the function of caps and copings.
Install a retaining wall.

5. Masonry Walls Single-wythe or multiple-wythe
Reinforced or unreinforced
Provide excellent structural performance
Easily maintained and attractive
Energy efficient due to high thermal mass

6. Energy Codes Most energy codes specify U-values
Heat flow through a building product based on difference between external and internal temperatures
R-value is thermal resistance of heat loss through a building product
R = 1/U

7. Solid Masonry Walls
Loadbearing or nonloadbearing

8. 6″ Masonry Walls with SCR brick
Nominal thickness of 2 2/3″ produces 16″ in six courses
Nominal 6″ wide and 12″ long

9. Four-Inch RBM Curtain and Panel Walls
Exterior nonloadbearing walls
Curtain walls
Not wholly supported at each story
Panel walls
Supported at each story and self-supporting between stories
Both types must be able to resist lateral forces

10. Design of Four-Inch Walls
Partially reinforced
Ladder- or truss-type reinforcement
Drainage space on inside of wall
Expansion joints
Brick Industry Association

11. Hollow Masonry Walls Walls built using solid or hollow masonry units
Separated to form inner and outer wall
Two types
Cavity walls
Masonry bonded walls

12. Cavity Walls Widely used in low- and high-rise buildings
Superior rain penetration resistance, thermal capabilities, sound transmission, and fire resistance
Continuous air space 2″ to 3″ wide

13. Construction of Cavity Walls
Exterior wythe
Usually a nominal 4″ thick
Solid or hollow brick
Interior wythe
4″, 6″, or 8″ thick
Brick, structural clay tile, or hollow or solid concrete masonry units

14. Cavity
Air space has insulation value and can be filled with insulation material for added reduction of heat transfer
Acts as a barrier to moisture
Must be kept free of mortar droppings

15. Weep Holes Required at bottom of cavity wall
Mortar opening creates void for moisture inside wall cavity to exit
Located immediately above flashing

16. Flashing Thin, impervious material Usually made of metal
Keeps any moisture that might collect in cavity away from inner wall
Portland Cement Association

17. Insulation
Rigid boards installed horizontally within air space against cavity face of backup wythe
Granular fill is usually poured directly into cavity from bag or from hopper
Brick Industry Association

18. Bonding
Adjacent wythes tied together with corrosion-resistant 3/16″ diameter steel or metal ties
Ties in alternate courses should be staggered
End of ties should be bent to 90° angles
Additional ties needed at openings

19. Flashing Diverts moisture out of cavity through weep holes
Continuous flashing at bottom of cavity and wherever cavity is interrupted
Over unprotected wall openings
At window sills, parapet walls, and spandrels

20. Weep Holes Must be provided wherever flashing is used
Located in joints of outer wythe immediately above flashing
Spacing is approximately 2′ O.C maximum
Weep holes using wick material should be 16″ O.C. maximum

21. Expansion Joints
Movement of outer brick wythe is greater than that in solid or composite walls
Expansion joints are recommended through outer wythe on each side of external corner where walls are 50′ or more in length

22. Hollow Masonry Bonded Walls
Used as foundation and exterior loadbearing walls
Not resistant to high moisture

23. Anchored Veneered Walls
Brick and stone masonry facing veneer
Veneer is attached, but not bonded to, backing
Veneer does not act structurally with rest of wall

24. Anchored Brick Veneer Construction
Nominal 3″ or 4″ thick exterior brick wythe is anchored to backing system with metal ties
Clear air space between veneer and backing
Wood frame, steel frame, concrete, or masonry backing system
Facing of masonry units or other weather-resisting, noncombustible materials

25. Moisture Resistance
Brick veneer wall assemblies are drainage-type walls that resist rain penetration
Flashing and weep holes work with air space to resist moisture penetration
Brick veneer with wood or metal frame backing is usually built with minimum 1″ air space

26. Brick Veneer Foundations
Brick veneer on frame backing transfers weight of veneer to foundation
Foundation brick ledge supporting brick veneer should be at least equal to total thickness of wall assembly
Foundations must extend beneath frost line

27. Masonry Wall Ties Noncorrosive metal ties
One tie for every 2 2/3 sq ft of wall area
Maximum spacing of 24″ O.C. in either direction
Nail must be located within 5/8″ of bend in tie
Brick Industry Association

28. Wire Ties Must be embedded at least 5/8″ into bed joint from air space
At least 5/8″ cover of mortar to exposed face
Corrugated ties must penetrate to at least half the veneer thickness and have at least 5/8″ mortar cover

29. Flashing and Weep Holes
Position above grade
As close as possible to bottom of wall
As close as possible above openings and below sills
Weep holes should be in head joints directly above flashing
Weep hole spacing
No more than 24″ O.C. for holes in which mortar has been completely removed
Maximum of 16″ O.C. for holes with wicking material

30. Lintels
Brick veneer backed by wood or metal frame must be supported by lintels over openings
Lintel materials
Loose steel
Stone
Precast
Concrete
Cast stone
Reinforced brick

31. Expansion Joints May be needed to allow for horizontal movement
Required in brick veneer when there are
Long walls
Walls with returns
Large openings

32. Composite Walls Two walls bonded together with masonry or wire ties
Vertical collar joint (narrow space between facing and backup units) prevents passage of water

33. Building an 8″ Composite Wall
First course of facing may be either headers or stretchers
All facing courses are laid in a full mortar bed with head joints completely filled
Facing headers are laid every seventh course
Mortar extruded on backside should be cut flush with trowel before it hardens

34. Building an 8″ Composite Wall (Cont.)
Wythes can be bonded across collar joint by parging backside of facing
Portland Cement Association

35. 12″ Composite Wall
Facing header course is laid overlapping the header block
Header block can be laid with recessed notch up or down

36. Resisting Moisture Condensation
Water affects many building materials
Condensation can be decreased through ventilation or dehumidification
Mechanical devices and heat exchangers remove moisture-laden air

37. Reinforced Masonry Walls
Steel reinforcement embedded in masonry units
Structurally bonded by grout core
Grouting techniques vary
Full bed joints are used

38. Reinforcing Masonry Walls
Maximum spacing of principal reinforcement should not exceed 48″
Primary use of steel reinforcement is in vertical members, lintels, and bond beams

39. Retaining Walls Reinforced masonry Two common designs Cantilever-Type
Gravity
Cantilever
Cantilever-Type

40. Grouted Masonry Walls Single- or multi-wythe
Similar to reinforced masonry walls but without reinforcements
Grout is added to core in loadbearing masonry walls to provide added strength
Other uses include filling bond beams and collar joint in two-wythe walls

41. Thin Brick Veneer Thin brick units approximately 1/2″ to 1″ thick
Give appearance of conventional brick wall
Most common face size has nominal dimensions of 2 2/3″ × 8″
Adhered veneer

42. Thin Brick Veneer Classifications
Thin bed set
Brick Industry Association

43. Thin Brick Veneer Classifications (Cont.)
Thick bed set
Brick Industry Association

44. Thin Brick Faced Precast Panels
Forming table creates size and shape of wall panel
Thin brick composes exterior face of panel, becomes bonded and embedded into panel when concrete mix is poured into form
Constructed indoors and delivered to site
Gage Brothers in Sioux Falls, SD

45. Chases and Recesses
Horizontal or vertical spaces for plumbing, heating ducts, electrical wiring, etc.
Chases are located inside of wall and are from 4″ to 12″ in width
Recesses are limited to 1/3 of wall thickness

46. Lintels Structural member placed wall opening to support loads above
Steel lintels should be supported on either side of opening for at least 4″
Reinforced concrete lintels should have a minimum bearing of at least 8″ at each end
Longer lintels should have greater bearing surfaces at ends

47. Types of Lintels

48. Detailed Brick Masonry Lintel
Brick masonry lintel with stirrups
Brick Industry Association

49. Movement at Lintels Slight movement occurs at location of lintels
Control joints are often located at ends
Noncorroding metal plate is placed under ends where control joints occur to prevent uncontrolled cracking
Full bed of mortar should be used over plate

50. Arches
Masonry units span an opening by transferring vertical loads laterally to adjacent masonry units, and thus to abutments

51. Arch Terminology

52. Arch Classifications Arches are normally classified by:
Curve of intrados
Function, shape, style
Arches are also classified as major and minor

53. Types of Arches
Brick Industry Association

54. Types of Arches (Cont.)
Brick Industry Association

55. Function of Arches Compression stresses are distributed through arch
Weight is diverted to abutments
Some may require steel reinforcements
Brick Industry Association

56. Arch Design
Odd number of units are used so keystone falls at center of crown
Arch voussoirs are usually in radial orientation
Different shapes and sizes of brick selected based on arch type, dimension, and desired appearance

57. Arch Spans Short spans Larger spans
Tapered brick is recommended to avoid wide mortar joints at extrados
Larger spans
Requires less taper of the voussoirs
Formed with rectangular brick and tapered mortar joints
Mortar joint should be between 1/8″ and 3/4″

58. Arch Depth
Dimension of arch at skewback that is perpendicular to arch axis, except in jack arches
Depends on size and orientation of brick used
Usually a multiple of the brick’s width
Arch depth should increase with increasing arch span

59. Brick Masonry Arch Construction
Two methods
Special shapes and uniform joint thickness
Units of uniform thickness with varying joint thickness
All mortar joints must be completely filled

60. Centering for Arches Temporary shoring supports masonry
Centering is usually made from wood

61. Jack Arch Construction
Supported by steel if opening is over 2′ wide
Steel must be bent to the camber
Each joint should be same width as entire length of joint
End joints are horizontal to radius of arch

62. Segmental Arch Construction
Number of courses is determined by length of extrados
Size of brick is determined by length of intrados
Rise should be 1/6, 1/8, 1/10, or 1/12 of span

63. Window and Door Details
Details are necessary for mason to plan ahead
Relationships between head, jambs, and sill to masonry wall
Brick Industry Association

64. Sills Channel water away from a building Single or multiple units
Built in place or prefabricated
Made of cut stone, brick, concrete, or metal

65. Joints for Movement in Masonry
Volume changes in masonry material result in movement
Joints allow for movement to occur and to prevent cracks
Types
Expansion joints
Control joints
Building expansion joints
Construction joints

66. Expansion Joints Separate brick masonry into segments
Prevent cracking due to changes in temperature, moisture expansion, elastic deformation, and creep
Horizontal or vertical
Located so as not to compromise structural integrity
Brick Industry Association

67. Control Joint
Creates a plane of weakness in concrete masonry to control location of cracks
Vertical opening through concrete masonry wythe
Must be located so structural integrity of concrete masonry is not affected

68. Building Expansion (Isolation) Joint
Divides building into separate sections so stresses developed in one section do not affect integrity of remainder of structure
Through-the-building joint allows adjoining parts of building to move freely from one another

69. Construction (Cold) Joint
Used where masonry work is interrupted
Mason terminates work at a vertical plane and then continues laying brick until that section of wall is complete
Next section of wall begins at construction joint
Located where least likely to impair strength

70. Bond Breaks
Prevent cracks due to differences in expansion and contraction rates of materials
Building paper or flashing separate two surfaces of masonry material
Used between floor slabs and foundations
Allow each element to move somewhat independently while providing support

71. Brick Masonry Soffits Enclose a building Provide attractive appearance
Large soffits requires expensive forming and shoring
Brick masonry soffit may be more efficient for small soffit area
Usually reinforced and grouted

72. Stone Quoins
Large square stones used at corners and around openings of building for ornamental purposes
Height is odd number of brick courses
Length is equal to one or more units used in wall

73. Garden Walls Freestanding structures Can be perforated Straight walls
Pier and panel walls
Serpentine walls
Can be perforated

74. Straight Walls Masonry texture and color give character
Thickness provides lateral stability against wind and impact loads
Different copings

75. Pier and Panel Walls
Series of relatively thin panels 4′ thick, braced by masonry piers
Easy to build and economical
Ideal for uneven terrain
Foundations are required only for piers

76. Serpentine Walls
Serpentine shape provides lateral strength so wall can be built 4″ thick
Radius of curvature no more than twice height above grade
Depth no less than 1/2 of height

77. Caps and Copings Channel water away from building
Cap is covering within height of wall
Coping is covering at top of wall
Single or multiple units
Tops slope in one direction or both directions
Made of brick, precast or cast-in-place concrete, stone, metal, or terra cotta

78. Corbels
Shelf or ledge formed by projecting successive courses of masonry out from face of wall
Used to achieve a particular appearance or to provide structural support
Horizontal projection should not exceed 1/2 thickness of wall or veneer
Projection of single course should not exceed 1/2 of unit height or 1/3 of unit bed depth

79. Racking
Masonry in which successive courses are stepped back from face of wall
When racking back to achieve desired dimensions, make sure cores of units are not exposed

80. Segmental Retaining Walls (SRW) and Hardscape
Constructed of high-strength concrete blocks or units made for dry stacking
SRW blocks are used to build retaining walls
Hardscape is intended for decorative purposes
Anchor Wall Systems, Inc.

81. Retaining Wall Products
Some have locking lip on lower back edge
Prevent forward movement exerted by earth pressures
Straight and beveled front units with uniform or tapered widths

82. Retaining Wall Installation
Prior to construction, prepare a layout plan that considers topography, drainage patterns, soil conditions, and local code restrictions