Brick Masonry.pptx

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1. UNIT - 4 BRICK BONDS

2. Building Elements: Brick Masonry walls

3. I N TRODU C T I O N  Masonry Construction of building units bonded together with mortar.  Brick masonry Construction of brick units bonded together with mortar.

4. Introduction The term “Masonry” is used to indicated the art of building the structures in either Stones or Bricks. The former type is called “Stone Masonry” The later type is called “ Brick Masonry” The b a si c a d v ant a g e o f the m a sonry f or th e l oad b eari n g structures is that it performs a variety of functions like: Affording architectural effect, Granting fire and weather protection, Providing acoustic and thermal insulation, Subdividing space, Supporting loads, etc.

5. Brick masonry is made up of bricks bonded together with mortar. Therefore two essential requirements of brick masonry is: Bricks: Bricks used in masonry can be of two types Traditional / Country bricks (23 x 11.4 x 7.5 cm) Standard size (19 x 9 x 9 cm) Some times bricks are also manufactured into special shapes and sizes for architectural purposes e.g. copings, cornices, sting courses, sloping walls etc. Mortar: It is a mixture containing a binding agent (cement / lime), aggregate and water thus acquiring stone like properties as a result of hardening. Mortars are used for filling joints as a binder in stone and brick masonry, for preparation of decorative and protective plasters.

6. Basic definitions Course: A course is a horizontal layer of bricks or stones. Stretcher: Stretcher is the longer face of the brick (19 cm x 9cm) A course of bricks in which all the bricks are laid as stretches on facing is known as a stretcher course or stretching course. Header: Header is the shorter face of the brick (9cm x 9cm) A course of bricks in which all the bricks are laid as headers on the facing is known as header course or heading course. Bed: It is the lower surface of bricks when laid flat and thus it is perpendicular to the line of pressure . It indicates the lower surface of bricks or stones in each course. Arrises: Arrises are the edges formed by the intersection of plane surfaces of a brick. They should be sharp, square and free from damage.

7. Basic definitions Lap: It is the horizontal distance between the vertical joints of successive brick courses. Perpend: Perpend is an imaginary vertical line which includes the vertical joint separating two adjoining bricks. Quoin: Quoin is a corner or their external angle on the face side of a wall. Generally quoin’s are at right angles, but in some cases their angles can be greater than 90 o also. Bed joints: Bed joints are horizontal layer of mortar upon which bricks are laid. Racking back: It is the termination of a wall in a stepped fashion. Tooting: It is the termination of the wall in such a fashion that each alternate course at the end projects, in order to provide adequate bond if the wall is continued horizontally at a later stage.

8. Basic definitions Quoin brick: The brick, which forms the external corner of a wall is known as “Quoin brick”. Quoin header: A corner header, in the face of wall, which is a stretcher in the side wall is known as “Quoin header”. Quoin stretcher: A corner stretcher in the face of a wall, which is header in the side wall is known as “Quoin stretcher”

9. Lap forms [CONCEPT CLARITY ]

10. Basic definitions Bat: It is the portion of brick cut across the width and hence a bat is smaller in length than the full brick. The following are SOME OF the types of bats used in brick masonry, which are defined by considering its relation to the length of a brick Half bat : If the length of brick is equal to half the length of the original brick, it is known as half bat. Three-quarters bat : If the length of the brick is equal to three quarters of the length. Bevelled bat : If the bat has its width bevelled then it is called bevelled bat. Bullnose: A brick with a rounded angle is termed as bull nose.

11. Picture of various types of Bat Quarter bat

12. Basic definitions Closer : A piece of brick which is used to close up the bond at the end of brick courses, is known as closer and helps in preventing the joints of successive courses to come in a vertical line. Generally the closer is not specially moulded. But it is prepared by the mason with the edge of trowel. The following are some of the types of closure Queen closer: This is obtained by cutting the brick longitudinally in two equal parts. It can also be made from two quarter bricks, known as the quarter closers , to minimize the wastage of bricks. A queen closure is placed near the quoin header to obtain the necessary lap. King closer: This is obtained by cutting a triangular portion of the brick such that half of header and half of stretcher are obtained on the adjoining cut faces. A king closure is used near the door and window openings to get satisfactory arrangement of mortar joints.

13.  BEVELED CLOSER It is a form of king closer in which the whole length of the brick (i.e. stretcher face) is chamfered or beveled in such a way that half width is maintained at one end and full width is maintained at the other end.  MITRED CLOSER It is a portion of a brick whose one end is cut splayed or mitred for full width. The angle of splay may vary from 45 to 60 . Thus one longer face of the mitred closer is of full length of the brick while the other longer face is smaller in length.

14. Picture of various types of Closures

15. Elevation of wall showing various terminology

16. 15 Basic Brickwork Terminology Bed Joi nt Head Joint Course - horizontal layer of brick

17. Half bat Queen closer King closer Full brick

18. Masonry Joints Flush Racked C o n c a v e Struck Weathered C o n c ave Vee Concave Joints Raked Joints

19. English Bond Flemish Bond Stretching Bond Heading Bond Garden Wall Bond Facing Bond Raking Bond Dutch Bond English Cross-Bond Zig-Zag Bond Silverlock’s bond Types of Bond

20. Wh y bon d i s necess a ry ??? Eliminates continuous vertical joints Imparts strength to the masonry Defective arrangement reduces strength & durability A wall having continuous vertical joints does not act as homogeneous mass

21. STRECTCHER BOND HEADER BOND ENGLISH BOND FLEMISH BOND FACING BOND ZIG ZAG BOND

22. Bonds Since masonry consists of a large number of individual units jointed together with mortar so as to form one mass, it is necessary to lay the units in such a way that, under load, the units act jointly. The most important rule to be observed in this connection is that vertical cross-joints in any course should be staggered and these should not be nearer than a quarter of brick length from those in the course below or above that course.

23. Types of Bonds in Brick masonry There are a number of brick laying arrangements in vogue-called ‘bonds’, of which those commonly used are: ‘Stretcher bond’, ‘ Header bond ’, ‘ English bond’, ‘Double & Single Flemish bond ’, Garden-wall bond, English garden wall bond Flemish garden wall bond Raking bond, Herring bone bond Diagonal bond English cross bond and Dutch bond.

24. STRE T CHER BOND

25. Stretcher bond In this type of bond, all the bricks are arranged in the stretcher courses. The stretcher bond is useful for one-brick partition walls; cavity walls as there are no headers in such walls. As this bond does not develop proper internal bond, it should not be used for walls having thickness greater than one-brick wall. Stretcher bond in the brick is the simplest repeating pattern.

26. Isometric view, Elevation and plan of Stretcher bond

27. HEADER BOND

28. Header bond In this type of bond, all the bricks are arranged in header courses. The overlap is usually kept equal to half the width of brick and it is achieved by using three-quarters brickbats in each alternate courses as quoins. This bond does not have strength to transmit in the direction of length of wall . Hence it is not suitable for load bearing walls. However this bond is used for curved surfaces in brickwork because stretchers, if used for curved surfaces, would project beyond the face of wall.

29. Isometric view, Elevation and plan of Header bond

30. ENGLISH BOND

31. English Bond In this bond, bricks in the facing are laid as alternate header and stretcher courses . The header course is commenced with a quoin header followed by a queen closer and continued with successive headers . The stretcher course is formed of stretchers, having a minimum lap of one quarter brick length. This bond is considered to give the best strength in masonry and is mostly adopted in all load bearing masonry that is to be plastered over . In this bond when the wall is only one brick thick, one face is fair and even, while the other face may be uneven due to slight variations in length and breadth of units.

32. Cont d … If the wall thickness is an even multiple of half-brick, the same course shows headers or stretchers in both front and back elevations. But if the wall thickness is an uneven multiple of half- brick, a course showing stretcher on the face elevation and header on the back elevation and vice versa is seen. A header course should never stat with a queen closer as it is liable to get displaced in this position. The queen closers are not required in the stretcher courses. In the stretcher course, the stretchers have a minimum lap of one- fourth of their length over the headers. For walls having thickness of two bricks or more , the bricks are laid as stretchers or headers only on the face courses of the wall. The interior filling is done entirely with the headers .

33. Isometric view of English Bond 1 brick thick wall Qu e en Closer Header Course Stre t c her Course H e a d e r Course Stre t c her Course Direction of Elevation view

34. Elevation of 1 Brick thick English bond

35. Plan for 1 brick thick wall (English Bond) H = Header S = Stretcher Q = Queen closer Fa c e Back Face B ack

36. Isometric view of English Bond 𝟏 𝟐 1 thick brick wall Direction of Elevation view Header Course Stre t c her Course Quarter Queen closer

37. Elevation of 1 𝟏 Brick thick 𝟐 English bond

38. Plan of 1 – 1/2 Brick thick English bond Quarter Queen closer ( or) Quarter Bat Queen closer Header Stretcher

39. Elevation of 1-1/ 2 Brick thick English bond Stop p ed end

40. Double Flemish bond

41. Introduction In e v ery cou r s e , h eaders and st r et c h ers are placed alternatively. Th e q ueen cl o ser i s put n e xt t o the quo i n header in alternate courses to develop the face lap. E v e r y h eader i s c e n t r a l l y su p p o r t ed o v er a s t r e t c h er below it. The Flemish bond may be divided into two groups: Double Flemish bond Single Flemish bond

42. Double Flemish bond In double Flemish bond , the headers and stretchers are placed alternatively in front as well as the back elevations . For this type of bond, the half bats and three-quarter bats will have to be used for wall thickness equal to odd number of half bricks. For wall thickness equal to even number of half bricks , no bats will be required and a stretcher or header will come out as stretcher or a header in the same course in front as well as back elevations. This bond gives better appearance than the English bond . But it is not so strong as the English bond as it contains more number of stretchers.

43. Elevation of Double Flemish Bond Stop p ed end

44. Plan of 1 Brick thick Double Flemish bond

45. Isometric view of 1 𝟐 𝟏 Brick thick Double Flemish bond

46. Plan of 1 𝟏 Brick thick 𝟐 Double Flemish bond

47. SINGLE FLEMISH BOND

48. Single Flemish bond In Single Flemish bond , the face elevation is of Flemish bond and the filling as well as backing are of English bond. Thus, in this type of bond, an attempt is made to combine the strength of the English bond with the appearance of the Flemish bond . This type of bond is used when expensive bricks are used for the face work. But in order to construct this bond, a wall of minimum 𝟐 thickness 1 𝟏 bricks is required.

49. Isometric view of 1 𝟏 Brick thick 𝟐 Single Flemish Bond

50. Front / Face elevation (i.e. it resembles Double Flemish bond) Stop p ed end

51. Back Elevation [Pictorial representation only] (i.e. it resembles English bond) Stopped end

52. Plan showing Flemish bond, English bond appearance in Single Flemish bond

53. Plan of 1 𝟏 Brick thick 𝟐 Single Flemish bond Stopped end

54. Comparison of English bond vs Flemish bond English bond Flemish bond Compact and stronger for walls especially of thickness more than 1½ bricks . Less St r on g er & compact than English bond. Less pleasing appearance More attractive & pleasing Cost is more Slightly Economical. (as it uses broken brick bats, although it requires some extra mortar for additional joints) No strict supervision required. Good W o r kmans h i p and caref u l supervision required.

55. Pictures of Various types of bonds Stretcher bond

56. Advantages of brick masonry  The brick masonry is cheaper as compared to stone masonry.  Bonding strength is very good.  In brick work , the mortar joints are thin and hence the structure becomes more durable.  No complicated lifting devices are necessary in brick work.  Brick work can be done by the less skilled labours also.  In Brick work good quality of bricks posses good fire resistance.  Due to regular size of bricks they are easy to handle.

57. Defects in brick masonry Sulphate attack Sulphate salts present in bricks work react with alumina content of cement . It occur in boundary walls Crystallization of salts from bricks Occur in masonry made out of brick which contain excessive soluble salts This phenomenon is also known as efflorescence. Corrosion of embedded iron or steel Iron or steel embedded in brick work gets corroded in the presence of dampness On corrosion the metal expands in volume and tends to crack the brick work.

58. English bond In general practice this type of bond is used. It c o n s i st s of a l t e r n ate c o u r s es o f h e a d e rs a n d stretchers . Considered as strongest bond in brick work For breaking vertical joints queen closer is placed after first header Heading course should never start with a queen closer Stretchers should have a minimum lap of ¼ their length over the header Even number of half brick walls present same appearance For odd number we see stretcher on one face and header on other In thick walls, the middle portion is entirely filled with header

59. Header course Stretchers course Queen closer ISOMETRIC VIEW OF ENGLISH BOND

60. Flemish bond Each course consists alternate headers and stretchers. Not as strong as English bond. Alternate course starts with a header at the corner. For breaking of vertical joints , closers are inserted in alternate courses next to the quoin header.

61. ISOMETRIC VIEW OF FLEMISH BOND H e a d er Stretcher

62. FLEMISH BOND  Every course consists of header and stretcher  Header are centered over stretcher  Every alternate course start with header  Closers are inserted next to the quoin

63. Single flemish bond: Combination of english and flemish bond In a course, facing is flemish and backing is english Cannot be adopted in walls having thickness less than one and half brick Provided for the attractive appearance of the flemish bond

64. Double Flemish bond: Each course presents the same appearance both in the face and back of the wall Every course consists of headers and stretchers alternately Best suited for consideration of economy and appearance This type of bonding is comparatively weaker than English bond