इंटरनेट मानक Disclosure to Promote the Right To Information Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public. “जान1 का अ+धकार, जी1 का अ+धकार” “प0रा1 को छोड न' 5 तरफ” “The Right to Information, The Right to Live” “Step Out From the Old to the New” Mazdoor Kisan Shakti Sangathan Jawaharlal Nehru IS 1597-1 (1992): Construction of Stone Masonry - Code of Practice, Part 1: Rubble Stone Masonry [CED 13: Building Construction Practices including Painting, Varnishing and Allied Finishing] “!ान $ एक न' भारत का +नम-ण” Satyanarayan Gangaram Pitroda “Invent a New India Using Knowledge” “!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता ह” है” ह Bhartṛhari—Nītiśatakam “Knowledge is such a treasure which cannot be stolen” ( Reaffirmed 2002 ) Indian Standard CONSTRUCTIONOFSTONEMASONRYCODEOFPRACTICE PART 1 RUBBLE STONE MASONRY ( First Revision) First Reprint MARCH 1996 UDC 693.152: 006.76 8 BIS 1992 BUREAU MANAK OF BHAVAN, INDIAN 9 BAHADUR NEW DELHI August1992 STANDARDS SHAH ZAFAR MARO 110002 Price Group 6 Building Construction Practices Sectional Committee, CED 13 FOREWORD This Indian Standard ( First Revision ) was adopted by the Bureau of Indian Standards, after the draft finalized by the Building Construction Practices Sectional Committee had been approved by the Civil Engineering Division Council. Use of stone masonry work is known and practised froth the earlier days and natural stone is extensively available in many parts of this country. The types of stone masonry~construction followed depends on local factors like physical characteristics of the stone, climatic conditions, workmanship, etc. Certain broad principles in laying, bonding, breaking of joints and finish should be complied with in order that the masonry develops adequate strength and presents a neat appearance. This standard ( Part 1 ) covers rubble masonry Part 2 of the standard covers ashlar masonry. which is commonly used in stone work in most cases. This standard was first published in 1967. The present revision has been taken up to incorporate the improvements found necessary in light of the usage of this standard and the suggestions made by various bodies implementing it. In the preparation of this standard several construction agencies in this country having wide experience in stone work have been consulted. Due weightage has been given to international co-ordination among the standards and practices prevailing indifferent countries. For the purpose of deciding whether a particular requirement of this standard is complied with, the final value, observed or calculated, expressing the result of a test or analysis, shall be rounded off in accordance with IS 2 : 1960 ‘Rules for rounding off numerical values ( revised)‘. The number of significant places retained in the rounded off value should be the same as that of the specified value in this standard. IS 1597 ( Part 1 ) : 1992 Indian Standard CONSTRUCTIONOFSTONEMASONRYCODEOFPRACTICE PART 1 RUBBLE STONE MASONRY (First Revision ) 1 SCOPE 3.6 Natural Stoae 1.1 This standard ( Part 1 ) covers the design and construction of rubble stone masonry. This includes the various types of stones used in building as given in IS 1805 : 1973. 1.2 This standard covers only construction practices generally met with in India. 1.3 This standard a) b) c) d) does not cover: stone facing and veneering stone lintels, stone stair case, and masonary for dams and masonary work. 3.7 Corbel Stone bonded well into the wall with part of it projecting out of the face of wall to form a bearing surface. work, 3.8 Cornice other A horizontal moulded projection which crowns or finishes either a wall, any horizontal division feature ( see of wall, or any architectural Fig. 3 ). massive 2 REFERENCES 3.9 Courses The Indian Standards listed in Annex necessary adjuncts to this standard, A are A layer mortar. of stones in a wall including the bed 3 TERMINOLOGY 3.10 Cramp 3.0 For following dressing as given A small piece of metal or the hardest or toughest stone procurable, sunk in mortices and fixed across joints as additional ties. The ends of metal cramps are bent at right angles and stone cramps are dovetailed ( see Fig. 1A ) . the purpose of this standard, the definitions and the terms pertaining to of stones and tools for masonry work, in 1‘S 1805 : 1973 shall apply. 3.1 Ashlar 3.11 Damp-Proof Stone masonry using dressed square stone blocks to given dimension and laid in courses. 3.2 Arris A sharp Fig. 8 ). L edge formed by two planes 3.13 Effloresceuce A powdery encrustment of salt left by evaporation. This may be visible on the surface or may be be1ow surface* 3.4 Bond units 3.14 Flashiug 3.5 Bond Stone ( Through Stone ) used to hold Selected long stones together transversahy ( see Fig. 4 ). movement Dowels.are small sections of metal, stone or pebbles bedded with mortar in corresponding mortice in bed or side joints or adjacent stones ( see Fig. lB ). The joint where one stone presses on another, for example, a horizontal joint in a wall or a radiating joint between the voussoirs of an arch (see Fig. 8 ). of structural layer which prevents 3.12 Dowels ( see 3.3 Bed Joint An interlocking arrangement in a wall to ensure stability. An impervious of moisture. Course a A sheet of impervious material fixed to a structure so as’to cover an intersection or joint where water will otherwise leak through. wall 1 IS 1597 ( Part 1 ) P 1992 3.15 Apron Flashing 3.18 Heading One piece combined cover and apron used to obtain a waterproof joint ( see Fig. 2A ). The infdling which forms the core wall ( see Fig. 4 ). 3.16 Cover Flashing 3.19 Jamb A flashing dressed down as a cover only over a separate upstand ( see Fig. 2B )- The part of the wall at the side of an opening. 3.17 Hammer Dressing A key between the stones by providing groove in one stone to take a corresponding concealed projection in the edges on the other stone ( see Fig. 1A ). lXX~~eurfacing . to a stone by means of a spa11 3.20 Joggle +OPING JOGGLE JOINT LJOGGLE CORNICE 1A Joggle Joint 16 Dowel Joint FIG. 1 JOGGLES, CRAMPS ANDDOWELS 2A Apron of a rubble Flashing FIG. 2 FLASHINGS 28 Cover Flashing IS 1597 ( Part 1 ) : 1992 3.21 Natural Bed 3.26 Quion The plane of stratification mentary rocks. that occurs in sedi- 3.22 Parapet A solid or pierced guard wall for flat terrace or a balcony ( or a bridge ) or a curb wall at the lower part of a pitched roof, which is exposed to atmosphere on face, back and top (see Fig. 3 ) J 3.27 Random Of irregular sizes and shapes. 3.28 Reveal The part the arris. COPING of the jamb between the frame and 3.29 Rubble Walling /-PARAPET Walling built of stones either irregular in shape as quarried of squared and only hammer dressed and having comparatively thick joints. Stones, for rubble walling are, as far as possible, angular. CORNICE STRING A quion is the external angle of a wall or building. The term is also applied to a stone specially selected and neatly dressed for forming such angle. COURSE 3.30 Scaffold A temporary erection of timber or steel framing with boarded platform at levels suitable for building, well in stages. 3.31 Sleeper Walls Low walls erected at intervals between the main walls to provide intermediate supports at the lowest floor. 3.32 Storey Rod WINDOW SILL A batten of exact height on which vertical dimensions are marked. It can also be used as a gauge-rod. 3.33 String Course A horizontal band, plain or moulded, usually projecting slightly from the face of a wall ( see Fig. 3 ). 3.34 Template or Bed Block A block of stone or concrete bedded on a wait to distribu the pressure from a concentrated load. FFIG. 3 SECT~~N;~~;;;;R WITH BRICK 4 NECESSARY INFORMATION For e5cient planning, design and execution of the work detailed information with regard to the following shall be ~furnished to those responsible for the work: 3.23 Pointing Pointing is a finish applied to the face of mortar joints in walling. 3.24 Plum Stone ( Pin-Header ) a) Layout plan showing the orientation of i’ the structure; b) Dimensioned details of the‘structures with details of sections ( to a suitably large scale, that is, l/20 or 1 mm - 20 mm ) and levels of foundations, finished ground levels, clear floor to floor heights of rooms, sizes or openings; etc, Selected long stones embedded vertically in the interior -of masonry wall to form a bond between successive courses. 3.25 Quarry Sap Quarry sap is the moisture quarried stone. contained in newly 3 IS 1597 ( Part 1) : 1992 c) Type 5.1.2.2 Durability d) Location and other details of openings, chases, embedments of service lines, such as for water supply, drainage and electrical installations and location and details of hearths, flues and chimneys. The stone shall be free from defects like cavities, cracks, flaws, sandholes veins, patches of soft or loose materials, etc. The percentage of water absorption ( see IS 1124 : 1974 for the method of test ) shall generally not exceed 5 percent. Generally the stone should not contain crypt0 crystalline silica or chert, miea or any other deleterious material like iron oxide, organic impurities etc. of stone and classes of masonry, types of bond and final finish for the masomy; the mixes of mortar to be used, etc; details of architectural features, mouldings and other special work; and NOTES 1 The selection of stones for durability is generally based on experience. An examination of structures, at least half a century old, where the partiruhtr iype of stone is used, will indicate the durability of the stone. If :ool marks are visib!r, and the edges and corners arc still sharp and true ;ino the surface is hard and shows no signs of deterioration, the stone is durable. 2 Stone from quarries having stratification at regular intervals will be of uniform quality generally. Where there are variations in rtratification, the stone shall be examined petrographically in accordance with IS 1123 : 1975. 5 MATERIALS 5.1 Stone 5.1.1 Types The common types of natural buildingtstones which are generally used are, granite and other igneous rocks, lime stone ( including marble ), sandstone, etc. For the properties of these types of stones reference may be made to IS 1123 : 1975. Size ofstone 5.1.2 Quality 5.1.2.3 All stones used for building purposes shall be strong, hard and durable as indicated in 5.1.2.1 and 5.1.2.2. Normally stones used in rubble masonry should be small enough to be lifted and placed by hand. The length of the stone shall not exceed three times the height and the breadth on base shall not be greater than three-fourth of the thickness of wall nor less than 150 mm. The height of stone for rubble maso:?:y may be up to 300 mm. 5.1.2.1, Strength The strength of building stones should be adequate to carry the loads imposed. For ashlar and coursed rubble masonry, the strength shall be as worked in accordance with IS 1905 : 1987, taking into account, the appropriate crushing strength of stone as given in Table 1, and also the type of mortar used. For random rubble masonry, the strength value shall be specified on the basis of local experience. NOTE - The selection and grading of stones for rubble masonry is largely done at site and the smaller stones are used in the hearting of the wall. Largescale supply will be facilitated if, as far as possible. preferred standard sizes for building stone ::r: ur~d as covered ili IS 1 I27 : 1970. Sandstone 30 300 5.2 Mortar Mortar to be used for stone masonr;: shall consist of mixes of cement and fine-aggregate; cement, lime and fine-aggregate; lime and fine aggregate of limestone pozzolana and fine aggregate. Suitable proportions and the cousiderations etIecting the choice of mortar are described in IS 2250 : 1981. 5.2.1 Cemrrrt Cement to be used for stone masonry mortar shall be ordinary Portland cement conforming to IS 269 : 19S9 or blastfurnace slag cement conforming to IS 455 : 1989 or Portland-pozzolana cement conforming to IS 1489 : lG76 or masonry cement conforming to IS 3466 : l988. v) Marble 50 500 5.2.2 Lime vi) Laterite 3 30 Table 1 Crushing Strength of Stones Minimum Crushing Strength -------_-, P----( in N/mm’ ) (‘in kg/cd ( see Note ) Type of Stones I% (~I) (2) i) Granite (3) (4) 100 1000 Basalt 40 400 iii) Limestone ( except very soft stone ) 20 2CO iv) ii) ) Lime to-be used for masonry mortar shall conform to the requirements of IS 712 : 1984. Emilime nently hydraulic and semi-hydraulic corresponding to Class A and B types of IS 712 : 1984 are as such suitable for use in masonry mortars, whereas fat limes corresponding to NOTE -The sources of information are: for(i) IS 3316 : 1974, for (ii) Bombay PWD handbook: for (iii), (iv) and* (v) DIN 1053 : 1952 ‘Wall execution’: for and design and masonry (vi) IS 3620 : 1979. 4 IS1597(Partl):1992 Class C will require mixing of SURKHZ or other pozzolana. This may be used in the form of either hydrated lime or lime putty. Quick lime shall never be used for structural purposes. white restricting cutting of the stones to the removal of inconvenient corners with a scabbling or spalling hammer. b) Brought to courses ( see Fig. 5 ) - This walling is similar to uncoursed random rubble except that the work is roughly levelled up to courses at intervals varying from 300 mm to 900 mm in height according to the locality and the type of stone used. The coirses heights usually correspond with the heights of the quoin and jamb stones. 5.3.2 Pozzolana SURKHZ shall conform to IS 1344 : 1981 and other pozzolanic materials, such as cinder and fly ash shall conform to the relevant Indian Standards. 5.2.3.1 Lime-pozzolana mixture if procured ready-made shall conform to IS 4098 : 1983. 5.2.4 Fine aggregate ( sand ) to be used for masonry~mortar shall conform to IS 2116 : 1980. For lime stone, it is customary and desirable to use the crushed stone as aggregate. Table 2 Recommended Use of Common Types of Stones ( Clause 6 ) 5.2.5 Water It:. Water to be used for masonry mortar shall be clean and free from injurious amount of deleterious materials and shall conform to IS 456 : 1978. 5.3 Metal (2) (1) i) Fittings ii) Metal fittings shall be non-corrodible. Galvanizing or coating with bitumen affords only a temporary protection against corrosion or iron and steel. Such treatments might cause staining in a sensitive stone. No iron~cramps and similar fittings shall be embedded or partially embedded on stone work. Type of Stone Recommended Specific Use (3) Masonry work submerged in water stones like *Dense granite and gneisses Masonry smoke fumes *Granite, work exposed to and chemical maso- quart&e Sandstone iii) For fine resistant nry iv) For carved or ornamental works, arches, etc Soft stone like marble, sandstone, etc v) For mason:y below pliqth ;;;rse or in contact with Dense stone like *granite, gneisses 5.4 Materials for Damp-Proof Courses Materials for damp-proof courses same as in 5.3 of IS 2212 : 1991. *For the recommended use of IS 3316 : 1974 mriy be referred to. shall be the granite stones, 7.1.2 Squared Rubble 5.5 Materials for Flashing and Weathering shall be a) &coursed ( see Fig. 6 ) - In this type, the stone are rougbly squared as risers OI jumpers and stretchers with varying heights; and are laid uncoursed. In selecting a stone the situation in which it is to -be used has to be considered. The recommended use of common types of stones for various situations has been shown in Table 2. b) Brought to courses ( see Fig. 7 ) - The stones are similar to those used for uncoursed rubble but the work is levelled up to courses of varying depth from 300 mm to 900 mm according to the locality and the type of stone used. Materials for flashing and weathering the same as in 5.4 of IS 2212 : 1991. 6 SELECTION OF STONE 7 DESiGN CONSIDERATIOK c) Coursed ($rst and second sort ) ( see Fig. 8 ) - Coursed walling is built in courses which may vary in height from 100 mm to 300 mm but the stones in any one course are roughly squared to the. same height. The faces of the stones may be pitched to give a rockface appearance or ma’y be dressed smooth. A variant of this fype of walling may be formed by the mtroduction of pinnings, that is,. smaller stones in the same courses, at intervals, producing a chequered effect. 7.1 Types The types of rubble walling may be divided as given in 7.1.1 to 7.1.4. 7.1.1 Rarldom Rubble a) Uncoursed ( see Fig. 4 ) -- This type of masonry is constructed of stones as they come from the quarry. The mason or wailer selects blocks of all shapes and sizes, more or less at random, and places them in a position to obtain a good bond, 5 IS1597(Part 1):1992 THROUGH STONE t--x Fro.4 ’ SECTIONXX RANDOM RUBBLE UNCOURSED MASONRY CtX l--X FICL 5 SECTIONXX RANDOM RUBBLE MASONRY BROUGHT TO COURSES SECTION FIG. 6 XX SQUARBD RUEBLE UNCOURSED MASONRY SEdTlON XX FIG. 7 SQUAREDRUBBLEMASONRY BROUGHTTO COURSES 6 Is1597(Part / 1): 1992 COPW JRSE I ARRIS r=JND STONE OlJlON lFIG. 8 SECTION X XX SQUAREDRUBBLE COURSEDMASONRY 7.1.3 Polygonal Rubble Warring ( see Fig. 9 ) Stone with no pronounced stratification is roughly hammer-pitched into irregular polygonil shapes, and bedded to show the face-joints running irregularly in aL1 directions. the masonry unit and normally this will occur only during the long spells of exceptionally wet weather. Cracks in the masonry provide seepage paths for running penetration. Where the stone is subject to attack by atmosphere, the penetrating moisture carries soluble sulphuric fumes and deposits them at the inner face of the wall, where they may cause disfiguration or decay. Table 3 Suitability of Rubble Walls for Yarioas Exposure Conditions ( Clause 7.2) Coortr-uction c’----Sheltered Solid R Solid, rendered R externally _Exposure Conditions -.-_A.T----_7 Moderate Severe N N R N NOTE - R denotes recommended and N denotes not recommended. FIG. 9 POLYGONALRUBBLEWALLING 7.4 Types of Mortar The choice of mortar shall essentitilly be based on local experience and practice for use with the stone selected and the chmatic conditions prevailing. The mortar shall also be duly workable, stand up well on the towel and spread out easily. shall stiffen up quickly as the rubble is laid, shall adhere strongly to the wall unit and shall develop sticient compressive strength on the masonry work. For details of mortar to be used in masonry work, reference may be made to IS 2250 : 1981. 7.2 Weatber_Protectioa An external rendering would contribute substantially to the weather resistance of solid wall. Depending upon local conditions, the wall may be of solid construction with or without exterior/ interior protection. The practice that is found to be satisfactory for the local environments shall be adopted. However, as a general guidance the recommendations givenin Table 3 may be followed. NOTE - Table 3 gives the suitability or otherwise of various types of some wall construction not less than 400 mm thick for the different conditions ofexposure ( for explanation of the terms, sheltered, moderate, severe, see Table 3 of IS 2212 : 1991 1. 7.5 Architectural Features 7.5.1 All-projecting architectural features, such as plinth projectionb, string courses, or cornices shall be effectively bonded by tailing into the stone work to ensure stability. Such architectural features shall be set straight and true into the finished joints as far as possible. 7.3 Rain Protection Protection against rain penetration would depend upon the rate of absorption of water by stone or by the mortar and also the extent of cracks present in the masonry. Penetration through body of the masonry is possible only -when the water absorbed at the external face is sufficient to fill certain portion of the pores in 7.5.2 When such features are not to be plastered over, they shall be built with stone which have high durability and resistance to moisture penetration. Stones specially made to required 7 IS 1597 ( Part 1 j : 1992 shape with the help of templates sheets, shall be used. cut out of more than two storeys, double scaffolding having two sets -of vertical support shall be provided. 7.5.3 Sun shades and projedting features which depend on the weight of misonry over them, for their stability shall be kept supported till such time when the masonry above is built and hardened sufficiently. 8.4 Handling The use of grip in the tops of stones is preferable to any method of holding the stone at the end, because It enables the stone to be set in final position before the tackle is released. Due care shall be taken to protect finished surfaces and edges of stone against danger during handling. The various methods employed in different situations for lifting stone are shown in Fig. 10. 7.5.4 All coping shall be dowelled or cramped. String courses shall tail at least 250 mm into the work and shall be throated on the underside. 7.6 Damp-Proof Course For the function, materials to be used, and the places where -damp-proof course is provided, reference be made to 6.8 of IS 2212 : 1991. 8.5 Tools Tools that are required for stone masonry work, such as plumb bob and line, straight edges, mason’s square, spirit level and trowel are des,; cribed in IS 1630 : 1984 and various types of mason’s hammer and chisels in IS 1129 : 1972. X7 Structural and Functional Characteristics 7.7.1 Structural Stability and Strength Reference may be made to IS 1905 : 1987, IS 1893 : 1984 and IS 4326 : 1976 for design with regard to structural stability. 8 GENERAL REQUIREMENTS MASONRY CONSTRUCTION 8.6 Watering Stones shall be sufficiently wetted before laying to prevent absorption of water from mortar. FOR 8.7 In all types of masonry, the particulars given in 8.7.1 to 8.7.12 shall be complied with. 8.1 Setting Out Details of setting JS 2212 : 1991. out is the 8.7.1 The stone shall be laid so that the pressure is always perpendicular to the natural bed. same as in 8 of 8.7.2 The courses (if any ) shall be built prependicular to the pressure which the masonry will bear. In case of battered walls, -the base of stone and the plane of courses ( if any ) shall be at right angles to the batter. 8.2 Dressing of Stones The dressing of stone shall be as specified for individual types of masonry work and it shall also conform to the general requirements for dressing of stone covered in IS 1129 : 1972. Other specific requirements are covered separately with respect to particular types of rubble stone work ( see 9 ). NOTE - In the case of a bridge pier having on both sides, tlie courses shall be horizontal. batter 8.7.3 In the case of coursed rubble masonry, if the heights of the courses vary, the largest stone shall be placed in the lowest course, the thickness Qf courses shall also decrease gradually to the top. 8.3 Scaffolding Siug1e scaffolding, except as mentioned in 8.3.1, having one set of vertical support shall be used and the other end of the horizontal scaffolding member shall rest in a hole provided in the The support shall be sound and masonry. strongly tied together with horizontal pieces over which the scaffolding planks shall be fixed. The holes which provide resting space for horizontal members shall not be left in pillars under one metre in width or immediately near the skew backs of arches. The holes left in the masonry work for supporting the scaffolding shall be filled and made good with concrete of M-15 before plastericg. The scaffolding shall be strong enough to withstand all loads likely to come upon it and shall meet the requirements specified in IS 2750 : 1964. 8.7.4 Vertical joints shall be staggered as far as possible. 8.7.5 Bell shaped bond stones or headers not be used. shall 8.7.6 All necessary chases for joggles, dowels, and cramps should be formed in the stones before hand. 8.7.7 Sufficient transverse bonds shall be provided by the use of bond stone extended from the front to the back of the wall and from outside wall to the’interiar, of thick walls atid in the latter case bond stones shall overlap each other in their arrangement. 8.7.8 At all angular junctions the stones at each alternate course shall be well bonded into t%e respective courses of the adjacent wall. 83.1 For pillars less than one metre in width or for first class masonr? ot for 8 building having 8 IS 1597 ( Part 1 ) : 1992 rSHACKLE RECTANGULAR STEEL PlECE CHAIN LEWIS THREE-LEGGED LEWIS r /-WEDGE -SHAPED CENTRAL PIECE WEDGE - SHAPED STEEL PIECE LEWIS MODIFIED THREE LEGGED LEWIS PIN LEWIS FIG. 10 TYPICAL DETAILS OF LIFTING APPLIANCES OF STONES strength, securely embedded in the stone work preferably in chases filled up by cement concrete ( see Fig. 11 ). lron holdfasts shall be given a protective coat of bitumen to avoid rusting. Woo&work faces in contact with stone work shall be treated with wood preservatives to prevent attack from insects and termites. The frames shall preferably be fixed ~simultaneously as the masonry work proceeds, as this construction will ensure proper bond without gaps between the masonry and the frames. 8.7.9 Where there is a break in masonry work the masonry shall be raked in sufficiently long steps for facilitating joining of old and new work. The stepping of the raking shall not be more than 4Y with the horizontal. 8.7.10 Masonry construction with too thin faces, tied up with occasional through stones or filled up with dry packing or small size aggregate shall be strictly prohibited. 8.7.11 The walls and pillars shall be carried truly plumb or to specified batter. up 8.9 Bearing of Floors, Roofs and Joints 8.7.12 Storev rods showing the heights of all doors and wcndows and other necessary information should be used at the rime of construction of masonry. It is not desirable to embed any structural timber in stone work as it is liable to be affected by dry rot. The ends of timber joints shall preferably rest on corbels or brackets but when built into a wall these shall be treated with preservative and in addition, space shall be left around them for free circulation of air. The ends df beams carrying heavy loads and of trusses shall be supported on templates of concrete or stone. 8.8 Fixing of Frames Where door or window frames of timber are fixed in the openings, the fixing shall be done generally with hold-fasts of adequate size and 9 IS 1597 ( Part 1 ) : 1992 DOOR FRAME \ NOT AND BOLT \ HOLDFAST--I CONCRETE FIG. 11 POSITION OF HOLDFASTSTO DWR Bed blocks should be set true to level and bedded in the same mortal’ as that used for walling. The ends of the steel beams or trusses embedded in masonry shall be built in with space all around for repainting or shall be protected with a thick bituminous coat and shall -be encased in rich concrete of M-15. The ends shall generally be supported on templates of plain or RCC of M-15 concrete or stone. BLOOK FRAME 8.11 Covering Green work shall be protected flom rain by sui~table covering. Masonry work and cement of composite mortar shall be kept constantly moist on all the faces for a minimum period of seven days. The top of the masonry work shall be left flooded with water, with the cl:>se of the day. Watering shall be done carefully so as not to disturb or wash out green mortar and use of perforated rose spout may be suitable. In the case of lime mortar, curing should commence two days after the laying of masonry atid shall continue for seven days. NOTE - In cilse of timber-groundfloor, the ends of the open-spaced timber joints supporting the floor boards should be nailed to wall plated on top of 125 mm walling, built either as an offset to wall or as a separate sleeperwall. 8.10 Jointing and Pointing 9 CONSTRUCTION All’joints shall be full of mortar. Pointing shall be avoided as far as possible, but where unavoidable it shall be carried out as the work proceeds using the same mortar as for bedding. If carried out by raking out the joint later on after hardening, specially prepared mortars shall be used. The maximum thickness of joints shall be 20 mm for random rubble and 10 mm for square rubble. The various types of pointing are shown in Fig. 10 of IS 2212 : 1991. 9.1 Random Masonry ( Uacoursed and Brought to coume ) 9.1.1 Dressing Stone shall be hammer-dressed on the face, the sides and the beds to enable it to come in proximity with the neighbouring Stone. The bushing on the face shall not be more than 40 mm on an exposed face. 10 IS 1597 ( Part 4 ) : 1992 9.1.2 Insertion of Chips Chips and spalls of stones shall be used wherever necessary to avoid thick mortar beds or joints and it shall also be ensured that no hollow spaces are left anywhere in the masonry. The chips shall not be used below hearting stones to bring these up to the level of face stones. The use of chips shall be restricted to the filling cf interstices between the adjacent stones in hearting and these shall not exceed 20 percent of the quantity of a stone masonry. 9.1.3 Hearting Stones The hearting or interior filling of a wall face shall consist of rubble stones not less than 150 mm in any direction, carefully laid, hammered-down with a wooden-mallet into position and solidly bedded-in mortar. The hearting should be laid nearly level with facing and backing. 9.I.4 Bond Stones Through bond stones shall be provided in walls up to 600 mni thickness, a set of two or more bond stones overlapping each other by at least 150 mm shall ,be provided in a line from face to back. In case of highly absorbent types of stones :f porous lime stone and sand stone, etc ) the bond stone shall extend about two-third into the wall, as through stones in such cases *may .give rise to damp penetration and, therefore, for all thickness of such walls a set of two or more bond stones overlapping -each other by at least 15C~mm shall be provided. Each bond stone or a set of bond stones shall be provided for every O-5 m* of the wall surface and shall be provided at I.5 m to 1.8 m apart clear in every course. and joints so as to give them approximateIy rectangular shape. These shall be square on all joints and beds. The bed joints shall be chisel drafted for at least 80 mm back from the face and for the side joints at least 40 mm. No portion of the dressed surface shall show a depth of gap more than 6 mm from a straight edge placed on it. The remaining unexposed portion of the stone shall not project beyond the surface of bed and side joints. The requirements regarding’ bushing shall be the same as for random rubble masonry ( .qee 9.1.1 ). 9.2.2 The heartmg or the interior filling of the wall shall consist of flat bedded stone carefully laid on their proper beds in mortar. The use of chips shall be rest&ted to the filling of interstices between the adjacent stones in hearting and these shall not exceed 10 percent of the quantity of masonry. While using chips it shall be ensured that no hollow spaces are left anywhere in the masonry. 9.2.3 Bond Stones The requirements regarding through or bond stone shall be same as for random rubble masonry but the‘se shall be provided at 1.5 m to 1.8 m apart clear m every course. 9.2.4 Quoin Stone The quoin which shall be of the same height as the course in which these occur, shall not be l_ess than 450 mm in any direction. 9.2.5 Face Stone 9.1.5 Quoin-Stone Quoin stone volume. shall not Face stone shall tail into the work for not less than their heights and at least one thirds of the stones shall tail into the work for a length not less than twice their height. These should’ be laid headers and stretchers alternatively. be less than 0.03 rnn in 9.1.6 Plum Storle The plum stone at about be provided. 900 mm interval 9.2.6 shall ‘The masonry shall be laid with or without courses as