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1 PowerPoint Presentation
Publisher The Goodheart-Willcox Co., Inc. Tinley Park, Illinois 1

2 Footings, Foundations, and Concrete
Chapter 11 Footings, Foundations, and Concrete 2

3 Chapter 11 Overview Introduction Staking Out House Location Excavation
Footing Shapes and Specifications Foundation Walls Concrete and Masonry Basement Walls Beams and Girders (continued) 3

4 Chapter 11 Overview Concrete and Masonry Concrete Blocks Paving 4

5 Learning Objectives Describe the procedure for staking out a house location. List the major considerations when designing a footing for a residential foundation. Analyze a typical floor plan to determine the appropriate foundation. (continued) 5

6 Learning Objectives Discuss the design considerations for wood, concrete, and masonry foundation walls. Calculate the load to be supported by a beam. Explain the purpose of a lintel. 6

7 Introduction A good foundation is very important.
It requires careful planning and design. Types of foundations: Masonry or concrete. All-weather wood. Slab type. Specialized CADD programs are available to aid the process. 7

8 Types of Foundations Masonry foundation. 8

9 Types of Foundations All-weather wood foundation. 9
(The Engineered Wood Association)

10 Types of Foundations Slab foundation. 10

11 Staking Out House Location
The plot plan provides the necessary dimensions for staking out the house. The task requires a measuring tape, contractor’s level, and possibly a transit. Locate each corner of the house. Use unit method for square corners. Check for accuracy by diagonal measurement. 11

12 Batter Boards Batter boards retain location of the foundation during construction. Locate them 4' outside the footing line. Corner stakes located with a plumb bob. Batter boards are attached to the stakes. Determine a control point (corner). Finished floor should be at least 8" above the grade. 12

13 Batter Boards Squaring a corner using the unit method. 13

14 Checking Accuracy Measuring diagonals. 14

15 Batter Boards in Place 15

16 Excavation Top soil should be removed and saved.
A backhoe generally used to excavate. Excavation for footings should extend at least 6" into undisturbed earth. The depth of excavation should also be at least 6" below frost penetration. No backfilling under footings. Soil tests determine soil suitability. (continued) 16

17 Excavation Excavation must be large enough to allow space to work on the foundation. Excavation wall should slope away from the bottom of the excavation. Slope angle will depend on soil type. Sandy soil requires a gentle slope. Wall may be nearly vertical in clay. 17

18 Frost Penetration Chart
Average depth of frost penetration in inches. (US Department of Commerce Weather Bureau) 18

19 Footing Shapes Footings increase supporting capacity of the foundation wall. Most houses require footings. Soil bearing capacity and weight of house determine the size and type of footing. Footings are generally poured concrete. Footing size is typically based on the foundation wall thickness. 19

20 Footing Shapes A footing expands load bearing area. 20

21 Footing Shapes General proportions of a footing. 21

22 Footing Specifications
Footing thickness generally equals the foundation wall thickness. Footing width is twice the wall thickness. Poor soil may require wider footings. Settling occurs during construction. Prevent uneven settling. Check code recommendations. Use steel reinforcing bars. 22

23 Fireplace and Chimney Footings
Fireplace and chimney footings are more massive than regular house footings. Should be reinforced with steel. 12 inches thick. Extend 6 inches beyond the perimeter of the chimney. Cast integrally with house footing. 23

24 Stepped Footings Stepped footings are necessary when building on hilly terrain. Steps should be placed horizontally. Vertical step height is no more than 3/4 of the distance between the steps. Steps should be multiples of 8 inches in masonry construction. Use 1/2" steel bars in footings. 24

25 Stepped Footing A stepped footing and foundation wall in masonry construction. 25

26 Foundation Walls Extend from the first floor to the footing.
May also be basement walls. Variety of materials may be used: Cast concrete, concrete block, pressure-treated wood, and stone or brick. Four basic types of foundation walls: T-foundation, slab foundation, pier and post foundation, and wood foundation. 26

27 Foundation Walls Foundation wall materials. 27

28 Foundation Walls Foundation types. 28

29 T-Foundations The T-foundation is the most common type of residential foundation. Name is derived from the shape. Footing and foundation wall are usually separate parts. Footings are usually cast in forms. Variety of applications of T-foundation. 29

30 T-Foundation Application
8" foundation wall with insulated slab floor. 30

31 T-Foundation Application
8" basement wall and footing. 31

32 T-Foundation Application
Insulated slab for perimeter heat. 32

33 T-Foundation Application
12" concrete block foundation for brick veneer on frame. 33

34 T-Foundation Application
Poured concrete foundation for brick and block wall. 34

35 Footing Forms Construction boards. 35

36 Footing Forms Manufactured forms that stay in place and serve as a drain tile. 36 (CertainTeed Corporation)

37 Slab Foundations A slab foundation is an extension of a slab floor.
Cast when the floor is placed. Sometimes called thickened edge slab. Should extend below the frost line. Reinforcement is recommended. Advantages: Requires less time, labor, and expense to construct. 37

38 Slab Foundation Application
Foundation for 10" cavity wall with slab floor. 38

39 Slab Foundation Application
Foundation for 10" masonry bonded wall with slab floor. 39

40 Slab Foundation Application
Thickened edge slab foundation for frame wall. 40

41 Slab Foundation Application
8" bearing wall partition on slab floor. 41

42 Pier and Column Foundations
Piers and columns are similar. Pier foundations sometimes replace T-foundations under the house. Piers often used in a long crawl space. Columns are used in basements where the span is too long. The difference between piers and columns is their height. A column has a footing and post. 42

43 Pier Foundation 43

44 Pier Variations 44

45 Post (Column) Foundation
A pipe or adjustable jack post is frequently used to support a beam. This is a column or post foundation. 45

46 Post (Column) Foundation

47 Wood Foundations Wood foundations are a below-grade, pressure-treated, plywood-sheathed stud wall. Popular where winter weather stops construction. Accepted by HUD, FHA, and FmHA. May be used in basement or crawl space construction. 47

48 Wood Foundation Typical wood foundation with crawl space. 48

49 Wood Foundation Typical wood foundation for basement. 49

50 Wood Foundation Construction
Placing the footing plate. 50 (Osmose Wood Products)

51 Wood Foundation Construction
Excavation should allow for 2" sand or 6" crushed stone for the footing. Sand base must be perfectly level and accurately located. Footing plates are 2" x 8", 2 x 10", or 2" x 12" pressure-treated lumber. Foundation walls are 2"x 4" or 2" x 6" stud frame. 51

52 Wood Foundation Construction
Fasteners are silicon, bronze, copper, or zinc-coated steel. Sheathing is pressure treated plywood. All framing lumber is pressure treated. Backfill after basement floor has cured and first floor is installed. 52

53 Wood Foundation Construction
Basement walls in place. 53 (Osmose Wood Products)

54 Concrete and Masonry Basement Walls
Factors influencing strength and stability of a basement wall include: Height and thickness. Bond of the mortar in a masonry wall. Vertical loading. Support from cross walls or pilasters. Support from first floor framing. Wall thickness depends on lateral earth pressure and vertical load. 54

55 Minimum Thickness of Basement Walls
55 (Portland Cement Association)

56 Pilasters Pilasters may be used to strengthen basement walls.
Built at the same time as the wall. Masonry wall pilasters are usually 8" x 16" in an 8" thick wall. Distance between pilasters should not exceed 15' in an 8" wall and 18' in a 10" wall. Pilasters are also used to support beams. 56

57 Pilasters 57

58 Wall Stiffeners Wall stiffeners provide an alternative to pilasters.
Accomplished by placing a Number 4 bar in one core of the block from footing to top plate. Another method is horizontal steel joint reinforcement at 16" intervals vertically. 58

59 Basement Wall Construction
Top of wall should be at least 8" above the grade in frame construction. Wood sills should be anchored to basement wall with anchors or clips. Provide at least 7'-5" headroom. Load bearing cross walls in basement are not masonry bonded to entire wall. Use tie bars 1/4" by 1-1/4" by 28" long. (continued) 59

60 Basement Wall Construction
Anchor clips. 60 (The Panel Clip Company)

61 Basement Wall Construction
A solid cap is recommended to spread the load over the wall. Dampproofing required on the outside of the basement wall: Parge coat and sealer. Excess ground water removal system may be needed. 61

62 Basement Wall Section 62

63 Water Removal Method Drain tile placement. 63

64 Water Removal Method Footing forms that serve as drain tiles. 64
(CertainTeed Corporation)

65 Beams and Girders Beams or girders support floor joists over long spans. May be wood or metal. Wood beams may be built-up or solid. Steel beams may be S-beams or W-beams. Size based on weight of the structure and the span. 65

66 Typical Steel Beams 66

67 Structure Loads Dead load is the weight of the structure itself:
Roofing, siding, joist, etc. Live load is the fixed or moving weights: Furniture, appliances, occupants, snow on the roof, etc. 67

68 Weight Supported by Beam

69 Load Assumptions First Floor and Second Floor Ceiling Walls Roof
Live + dead load = 50 pounds per square foot. Ceiling Live + dead load = 30 pounds per square foot. Walls Dead load = 10 pounds per square foot. Roof No load on beam. 69

70 Weight Calculations Example
Two Story Frame Structure 28' x 40'. Area of the House 1120 square feet per floor. Wall Area 320 square foot per wall. Assumes a bearing wall on each floor. 70

71 Weight Calculations Example
Foundation of the house. 71

72 Weight Calculations Example
Weight of first floor = 56,000 lbs. Weight of second floor = 56,000 lbs. Weight of ceiling = 33,600 lbs. Total weight = 145,600 lbs. Half bears on the beam = 72,800 lbs. First and second floor wall weight total = 6,400 lbs. Weight bearing on the beam = 79,200 lbs. 72

73 Weight Calculations Example
W-beam span and load table. 73 (American Institute of Steel Construction)

74 Weight Calculations Example
Length of beam = 40 feet. Three columns reduce span to 10'-0" and 19.8 kips(1 kip = 1000 pounds). An 8" x 6 1/2" WF beam will support 23 kips. 74

75 Weight Calculations Example
Three supporting posts are added. 75

76 Weight Calculations Example
Post Selection Size is determined by weight to be supported and length of post. Post must support 26 kips. Post length is 8 feet. Chart (Figure in text) shows that a 3" post will support 34 kips. 76

77 Weight Calculations Example
Weight supported by each post. 77

78 Weight Calculations Example
Steep pipe columns load table. 78 (American Institute of Steel Construction)

79 Lintels A lintel is a horizontal structural member that supports the load over an opening. Materials Precast concrete, cast-in-place concrete, lintel blocks, steel angle. Bearing surface of steel angle lintel extends into the masonry at least 4". 79

80 Types of Lintels 80

81 Precast Lintel In a masonry wall. 81

82 Steel Angle Lintel In a brick wall. 82

83 Concrete Concrete is ordered by the cubic yard.
One cubic yard is 27 cubic feet. A “six-bag mix” recommended. Concrete is composed of cement, sand, large aggregate, and water. It requires 28 days to fully cure at 70°F. 83

84 Concrete Finishing A screed used to smooth the surface.
A float used to embed large aggregate, remove imperfections, and consolidate mortar. A trowel used to develop a hard, smooth surface. 84

85 Contraction Joints Contraction joints are used to minimize and control cracking. Place in line with interior columns. Place at changes in width of slab. Maximum spacing of joints is 20 feet. 85

86 Floor Slabs A concrete floor slab should be placed on 4" to 6" of compacted sand. Slab thickness is 4" minimum. Slabs should not be bonded to footings or columns. A 1" thick sand cushion may be used to separate the slab from the footing. 86

87 Floor Slab Section 87

88 Concrete Blocks Used to form exterior and interior walls.
Variety of sizes and shapes available. Hollow concrete masonry units. Basic size is 8" x 8" x 16". Actual size is 7-5/8" x 7-5/8" x 15-5/8". Designed for a 3/8" mortar joint. Decorative blocks are available. 88

89 Common Concrete Blocks

90 Decorative Concrete Blocks

91 Paving A rigid paving system is installed on a concrete base.
Use Type M mortar for rigid paving. A flexible paving system is installed on compacted sand and crushed stone. Prevent creep with rigid edge restraint Paving units should conform to ASTM C902. Use 2-1/4" pavers for driveways. 91

92 Brick Paving 92

93 Flexible Paving System
Spreading the crushed stone base. 93

94 Flexible Paving System
Leveling the setting sand bed. 94

95 Flexible Paving System
Rigid edge restraint prevents creep. 95

96 Flexible Paving System
The pavers for this driveway turnaround are 2-1/4" pavers. 96

97 Glossary Batter Boards.
Used to retain the location of the foundation during excavation and construction. Bearing Wall. Designed to support part of the load of the structure. Cement. Composed of a mixture of lime, silica, alumina, iron components, and gypsum. Concrete. The result of combining cement, sand, aggregate (usually stone or gravel), and water. 97

98 Glossary Contraction Joints.
Grooves cut into concrete to minimize or control cracking due to temperature changes. Creep. Horizontal movement of a permanent object, such as pavers, or concrete slabs. Dead Loads. Static or fixed weights of the structure itself; examples of dead loads are the weights of roofing, foundation walls, siding, joists, etc. 98

99 Glossary Flexible Paving System.
Consists of a well-compacted subgrade beneath a layer of crushed stone, a sand setting bed, and fine sand between the pavers. Float. A short board, about a foot long, with a handle attached to one of the flat sides and used to embed the large aggregate just beneath the surface; remove any slight imperfections, lumps, and voids to produce a flat surface; and consolidate mortar at the surface in preparation for final steel-troweling. 99

100 Glossary Footings. Increase the supporting capacity of the foundation wall by spreading the load over a larger area. Kip. A unit of weight measurement; one kip is one thousand pounds. Lintel. A horizontal structural member that supports the load over an opening such as a door or window. 100

101 Glossary Live Loads. Fixed or moving weights that are not a structural part of the house; examples include furniture, occupants, snow on the roof, wind, etc. Parge Coat. A thin coat of plaster over the foundation wall. Pier Foundation. Consists of piers and footings. Post Foundation. Consists of columns (posts) and footings. Columns are taller than piers. 101

102 Glossary Pilaster. A rectangular column that projects from a wall; also used for additional girder or beam support Rigid Paving System. Consists of a well-compacted subgrade, a properly prepared base, a reinforced concrete slab, a mortar setting bed, and brick paving with mortar joints between the pavers. Screed. A long straightedge, usually a board, that is worked back and forth across the surface to bring excess water to the surface and settle the aggregate. 102

103 Glossary Slab Foundation. An extension of a slab floor; it is placed at the same time the floor is cast and is not a separate unit. Stepped Footings. Frequently necessary when building on hilly terrain. T-Foundation. The most common type of foundation; the name is derived from the shape of the foundation and footing, which look like an inverted T. 103

104 Glossary Trowel. A rectangular tool used in a circular motion to further harden the surface of concrete and develop a very smooth finish. Wood Foundations. A below grade, plywood-sheathed, pressure-treated stud wall; known by several names: permanent wood foundation (PWF), all-weather wood foundation (AWWF), and treated wood foundation. 104

105 Glossary 9-12-15 Unit Method.
These proportions define a right triangle and establish a 90 degree angle corner. Measure 9 units along one leg of the corner and 12 units along the other leg. The distance between these two endpoints should be 15 units. Adjust the legs of the angle until the distance is exactly 15 units. 105

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