If the design drawing for the electrical layout changed after pouring concrete on the slab, then that would be a problem, so, in order to resolve the said problem, you have to discuss with the engineer or consultant at the earliest possible time.
The engineer most probably will ask the “method statement or procedure” on how to resolve it. And the method statement below is the one you can propose as this was what we’ve proposed too.
Here is the method statement for chasing ceiling for the new location of light points and junction box.
1. Scope of Work
The purpose of this method statement is to describe the measures and ways of rectification works for chasing ceiling as per project specification and project quality plan.
2. Field of Application
This method statement would be used to make sure the proper way of chasing the ceiling on the new line of conduits to the light points for all the flats of first floor Block-A of this project.
3. Purpose
The purpose of this method is to define the specific tasks to be performed by Company relating the chasing ceiling works and to make sure quality of the output including the safety of the works.
4. Reference
• Design Layout Drawing / Shop Drawing
• Specification Section 00000 Concrete Works
• Material Approval for repair material
5. Material
• Cement Mortar (Premix approved by Engineer for repairing concrete)
6. Manpower
• Construction Manager
• Site Engineer
• QAQC engineer
• Safety officer
• Scaffolder
• Foreman
• Helpers
• Carpenters
7. Equipment & Tools
• Scaffolding
• Handheld concrete cutter/grinder
• Chisel
• Hand tools consisting of hammer, steel tape, suitable grouting tools etc.
• Personal Protective Equipment
8. Work Methodology
8.1 Preparation prior to start chasing ceiling
8.1.1 The line of the PT duct would be marked onto the ceiling by the Post Tension subcontractor representative to avoid clashing to the new location of the light points/junction box. The line of new conduits, junction box, and new light points would also be marked.
8.1.2 Clearance to be given by PT engineer, whenever necessary.
8.1.3 Inspection would be raised to the engineer for the marked PT and MEP lines prior to proceed chasing work.
8.2 Chasing of Ceiling
8.2.1 Working platform would be provided by the use of scaffolding or movable scaffold, it would be erected below the working zone by the certified scaffolder. Barrication would be provided during work commencing.
8.2.2 Erected scaffold shall be inspected and green tag would be placed before the operatives can do the work.
8.2.3 Chasing would commence only after the approval of the marked location of the conduits, junction box and light points.
8.2.4 The new marked location of the junction box and light points shall be cut via hand-held cutting machine. Sizes of the cut shall be wider than the size of junction box and light points to allow placement of concrete repair material.
8.2.5 The new marked line of PVC conduit shall also be cut by handheld machine.
8.2.6 The depth of the chased concrete shall not exceed the required depth. The foreman and site charge-hand shall monitor the chasing work in order to avoid inaccuracy.
8.2.7 Ensure that the operatives involved in the chasing of the ceiling should wear appropriate PPE in order to avoid injuries.
8.2.8 Proper lighting would be provided whenever necessary.
8.2.9 Inspection would be raised for approval of the engineer prior to MEP installations.
8.3 Application of FRS Cement Mortar over installed PVC conduits and sides of Junction Box and light points
8.3.1 The approved material cement mortar (Fibre Reinforced Shrinkage Mortar) shall be used for closing and repairing the chased area.
8.3.2 Cleaning would be done prior to filling the area and unsatisfactory conditions shall be removed before proceeding any grout applications.
8.3.3 Priming: FRSCM must be applied before the bonding agent dries while it is still tacky to achieve a better bond between the fresh and cured section.
8.3.4 Mixing: For mixing process, a slow speed drill (200 – 250rpm) fitted with a suitable paddle is recommended. Place (4.0 liters of cold clean water in the mixing bucket. With the drill and operation, add the entire content of the 25kg bag of FRSCM while mixing continuously till a lump uniform consistency mix is achieved. Powder must be always added to water.
8.3.5 Allow the obtained mix to stand for about 3 minutes and then remix before application. Under no circumstances should partial mixing be considered.
8.3.6 Application: Apply the FRS cement mortar manually with a trowel or a spatula with full compaction, to the primed substrate while it is still tacky.
8.3.7 The minimum applicable coat thickness is 10mm and the maximum thickness shall be 50 mm for vertical and 25 mm for overhead sections. For small horizontal sections, thickness should be from 10mm up to 100mm. Application thickness is dependent on repair size and granulometry. High build applications can be achieved through temporary formwork.
8.3.8 If the application of the second coat is necessary the previous layer should be cross-hatched and allowed to take up initial set before applying the next coat.
8.3.9 Use trowel or sponge for the finishing touch.
8.3.10 The repaired area shall be cured in accordance with good concrete curing practice and protected by drying winds. A water curing shall be used by spraying. Curing should begin as soon as final finish is achieved.
8.3.11 Application and further methodology shall be as per Material Technical Data Sheet recommended by the manufacturer.
8.4 Application of Spray Plaster
8.4.1 Grinding would be made prior to application of spray plaster course on the joints, if necessary.
8.4.2 Application of the succeeding spray plaster paint shall be done as per approved paint system. Ensure that the paint system is followed as per the manufacturer’s recommendation or technical data sheet.
8.4.3 Final paint application would be inspected for engineer’s approval.
8.4.4 Mock-up to be provided prior to proceed succeeding works.
9. Responsibilities
• Company Construction Manager shall be responsible for the overall implementation of this method statement.
• Company Safety officers shall ensure implementation of all safety procedures & safety measures related to the nature of works being carried out and in accordance with the project HSE plan.
• Company site QA/QC Engineer is responsible for implementing the related QA/QC Works as detailed in a quality plan.
10. Quality
• Company QA/QC staff shall monitor and ensure that documents such as Method Statement shall be approved before commencing chasing ceiling work.
11. Safety
• All works shall comply with the safety instruction/procedure as set out in the approved project HSE plan and all safety recommendations of local authorities shall be followed.
• All works should comply with safety procedure / instruction as set out in project safety plan.
• Basic PPE to be worn by all staff.
• Sufficient lighting would be arranged during the works when required.
Visit this website: Civil Engineering Guide