Interiors Sources Decor LLC. Method Statement BLOCK WORK. Civil Works 6/26/2016

Transcription

1 Method Statement BLOCK WORK Civil Works 6/26/2016 The purpose of this Work Method Statement for Block Works (Concrete Masonry Units) is to outline and describe in detail the procedure such as setting and lay-out plan on actual location, erection of scaffolding, mixing of cement mortar, mounting/laying of blocks and all other related activity. Inform all concerned supervisor including workers the value and importance of this activity prior to implementation. This activity should be performed with strict compliance and implementation of Safety Requirements & Procedure and project specifications to complete the work both for exterior and interior masonry walls.

2 TABLE OF CONTENTS 1. BLOCK WORK DRAWING AND DETAILS 2. STACKING BLOCKS 3. SCAFFOLD AND CLEAN WORKING AREA 4. LIFTING, SHIFTING & STORING 5. SCOPE 6. TOOLS EQUIPMENT PLANT 7. STARTING THE BLOCK WORK 8. BLOCK LAYING ALIGNMENT JOINTING 9. STRIKING JOINTS 10. CURING 11. TOOL BOX TALK ON

3 BLOCK WORK DRAWINGS AND DETAILS Detailed layout of the building showing room dimensions, thickness of walls at various locations in the building Details of openings (with sizes) to be provided in the walls for doors, windows, ventilators, exhaust fan openings & other openings Details of door, window, ventilator frames and their fixing means like holdfasts, anchor bolts etc and their levels Details of cross walls to ensure proper bond in main walls Location details of concealed items such as electrical conduits, telephone conduits, conduits for TV Antenna wires and cables Location details of items such as water supply pipes with details of inlet, outlet and crossings of service lines, sanitary pipes with details of inlet, outlet and crossings of service lines, openings or holes for positioning of water closet p / s traps, openings required for air conditioning ducts, pipe sleeves to be left in walls for other service pipes STACKING BLOCKS Blocks shall be stacked properly near the place of work (too large a quantity must not be stacked near the work area thereby causing safety hazard) Height of the stack should be one meter if stacks are non-interlocking arrangement, and if interlocking arrangement not more than 10 block height.

4 SCAFFOLD & CLEAN WORKING AREA Scaffolding should be braced adequately Scaffolding should be checked for the load carrying capacity and ensure no overloading. Working space should be clear from rubbish, waste mortar etc. so that easy access is ensured Use only narrow and podium scaffold only for block works with safe platform LIFTING, SHIFTING & STORING Unloading, Lifting, shifting of materials manual/mechanical transporting of blocks etc. have to be carried out by workers who are properly trained. Otherwise this may leads to serious injuries to workers since blocks are heavy Dry mix and cement should be kept in a dry location. Do stack the blocks on a proper platform & clean surface. Do stack blocks at just convenient location for immediate use. Do not over rule safety aspects to achieve timely completion

5 SCOPE This work procedure enumerates the scope of masonry work to be executed in the project as specified in the approved drawings and at places when instructed by the Engineer-in-charge. TOOLS, EQUIPMENT & PLANT Standard tools that listed below should keep available at site, those are: Electric drill & Masonry bits Measuring tape Trowels Mechanical mixer Laser levels Mixing Tray Scaffold Podium Spirit level 3 Bucket Scaffold Narrow Mason (club)hammer Wire brushes 3 Meter aluminium straight edge Mason Square Chisels Wheel barrow Line tread Mason brick hammer

6 STARTING THE BLOCK WORK Make sure all the materials are available at work area including dowel pin and other accessories Obtain access clearance from General Contractor Mark on the surface to establish the wall lines to attain proper layout of block work & maintain mark till the first course is fully laid. Obtain approval from General contractor on marking Scrub & clean with proper tool, the concrete or block work surface where new block work is to be done. Where usage of steel anchor or mesh etc, are specified for bonding block work with concrete, fix the anchors in position so that they are embedded properly in the courses. Before commencing block work, check reference points such as bench mark, lintel level, bed block level, cross beam level etc & be sure where to terminate the top most block course, after the same is studied in detail as stated above. Blocks should not be damp at the time of starting masonry. When much water is present on the blocks then mortar will become watery leading to a weak masonry. The blocks must be semi dry or skin wet. Mix quantity of mortar, which will be consumed in next 2 hours only. Mixing shall be done with proper measurements of ingredients. Mixing platform must be clean and protected from bonding to slab. Mixing of mortar shall be done in accordance with construction standard. (If more quantity is mixed and will not be consumed within the time, cement will start setting leading to weaker masonry). Add water to the dry mix of cement sand in required quantity. Neither wet cement nor wet sand is to be mixed. Bulk age of sand shall be considered while adding water to the dry mix. Prepare a scheme of scaffolding, draw a sketch and pass on the same to workers for execution. Ensure safety aspects such as stability, proper joints etc. Check and ensure availability of scaffolding materials, access ladder or staircases, working platforms etc. The maximum length of block wall without a break has to be limited to 6m. If wall is beyond this length vertical mullions have to be introduced. Where such mullions and

7 horizontal members are not given, please refer the case back to Architect / consultant for introduction of these members. BLOCK LAYING, ALIGNMENT AND JOINTING Carry out one row of block work with dry bond (i.e. without mortar, lay the blocks in position), the wall to establish the proper spacing of blocks. Lay mortar for full bed width and for a length of 3 blocks at a time, and to 12mm thickness. Lay one block at a time & gently press it on the mortar bed. Use a line thread from one end to end All block work shall be plumb, square and properly bonded. The joints shall not be broken. Excess mortar coming out on the edge (while pressing block in position in bed mortar) to be taken by trowel & buttered to the cross directional joint or head joint surface of the next block being laid. The thickness of courses shall be uniform with courses horizontal. Use straight edge & spirit levels on top of the blocks laid & check the top level. Make sure that the spirit level is in working condition & read the bubble carefully. Use laser tools for levelling if available. Lay the last closure block in the course, to close the bond and locate it to be near the centre of the wall normally. Butter both edges of closure block with mortar before lay. Repeat the above points for building more courses. After every two course of block work lay, check the verticality using plumb bob, sight down the wall. The whole block work to be built in uniform layers. For pointed masonry without plaster, smooth textured concrete block shall be used. The face of blocks work shall be kept clean at all times. Where block are to be used for load bearing walls, the uppermost layer of block masonry supporting slab or other structured members, shall be solid or treated as directed.

8 STRIKING JOINTS As soon as mortars in the joints have initially set, use a proper tool and strike the vertical joints first. The horizontal bed joints are to be raked next to a depth of 10 mm. After striking joints brush the wall surface head joint first & bed joints last to complete brushing. If, it is exposed block work without any plastering, the striking of joints should be 15mm in depth instead of 10mm Height of Construction No part of wall during construction shall raise more than one and ahalf meter above the general construction level.

9 CURING In hot & dry weather the mortar is likely to dry up before it has attained its final set in the block work. This leads to crumbling of mortar and resulting in weak block masonry. This shall be prevented, by keeping the new block work constantly wet, for at least seven days. Traditional floor screed basically consists of sand & cement mixed at a ratio of between 3 to 5 parts sand & 1 part cement. In the majority of cases 4 to 1 is quite sufficient.

10 TOOL BOX TALK ON: 1. Importance of PPE 2. Use and service of hand tools and electrical tools 3. Safe handling of power supply 4. Use of mechanical equipment and service 5. Housekeeping safety 6. Risk Assessment 7. MSDS (Material Safety Data Sheet) 8. Access clearance 9. Lifting, Shifting and Storing 10. Rest Area 11. Restriction of Mobile and Radio 12. Noise restriction 13. Cutting of materials that makes noise and dust 14. Approved shop drawing 15. Working at height 16. Use of scaffold