Tools used for False ceiling works:
Drilling machine, taping Knife, Scaffolding ladders, stand, self-levelling laser, rawlplug, Electric drill with clutch attachments, circular saw, cutting tool, applicator, Line threads, Straight edge, connecting clip, joint paper tape, plumb bob, spirit level, level tubes, line marker, pencil, stud interlocking tools, chisel, hammer, hack saw, crimping tool, foot lifter, screw driver, screws, tester, Level Clip, soffit cleat, level adjuster.
Cutting of Gypsum boards :
- Gypsum boards can be simply cut either its width wise or lengthwise. A line is drawn using line marker or pencil before cutting. Cutting should be done on front face of the board by using cutting knife.
- With both hands simultaneously pressed on the board, and the gypsum core will split exactly in line with the cut on its side face. Then the board is turned over and the other side of paper also to be cut with the cutting knife.
- Only when bulk quantities of Gypsum boards cuttings are required, the necessity of circular handsaw will come into picture, otherwise with the help of normal saw, boards can be easily cut and curves cutting can be done with an electric tool.
- First marking is to be done for circular holes for electrical plates, wires, fixtures and then drilling up to 60 mm to 80 mm by using still high speed drill. All cut-outs to be made using standard Electrical or carpenters’ tools.
- To overcome the irregularities of Gypsum board edges after its cutting, smooth planing is required for levelling and can be done by placing number of boards together or for single board, also gentle sanding by sand paper, uniformity and accurate level of planing will obtained.
- Uses : Gypsum boards can be used for decorative purposes as curved line, turnings, irregular shapes and curvatures. For this water spraying is to be done for either sides of board till it is wet. Wet boards should be bent gradually with utmost care, then fixed in the required position, after fully dry, then jointing to be done.
Handling and storage :
- Gypsum boards are unloading by manual skilled workers only. Always bear in mind that boards are not to be lifted on their short edges and not supposed to hold in horizontal plane Position. Carry the boards on the edges, holding on long Edge by two men and supporting top edge to avoid breaking due to bending.
- Always the boards should be stored under enclosed room protects from rain and water. They should be rested over wooden planks or runners at 18” intervals on level floor.
- Caution: Gypsum boards never be stacked on its edges for long durations without its usage at site, which leads to distortion.
Setting out and marking will be done as per approved architectural drawing. Height of ceiling for all areas to be marked well in advance with the help of dumpy level. The same will be transferred on all the corners and chalk lines or marker lines will be marked.
Fixing of Wall Angles:
All wall angles should be fixed along the marked ceiling line depending on the substrate at 600 mm c/c spacing. Before fixing the wall angle, the substrate should be finished with necessary finishes as per the finishing details.
Fixing of suspended vertical Hangers:
Fixing of hangers should be done as per the approved architectural drawing layout details, by using only reputed brand of approved hanger anchorage fixing to the ceiling. All the location points of the hangers marked on the ceiling should be reviewed by Project in charge, QA engineer and consultant. After completion of all works of MEP (Mechanical, Electrical and Plumbing) and clearance certificate from MEP Engineer, hangers should be fixed at a spacing of 900 mm or 1200 mm c/c in both directions.
The framework to be done as per approved architectural drawings and with reputed brand of approved materials. Framing members like Main Runners and GI Channels of 0.55mm thick should be placed at regular intervals of 900 or 1200 mm distance. Heavy weight embedded fixtures should not be resting over these frame work, instead it should be directly anchored to the ceiling with independent supports.
Framework Inspection and MEP Clearance:
After completion of framework, concerned areas including MEP, civil, architects and consultants should be called for inspection. Inspection request should be raised on approved formats for first fix and second fix of ceiling. After obtaining the green signal from MEP, Closure work for all cut-outs and opening voids should be started by Gypsum board installation. Gypsum boards of approved and reputed make should be fixed to the framing using gypsum screws at 200 mm c/c. For Tile ceiling, the void closure should be done by placing calcium silicate tiles on the entire grid frame.
Taping, Jointing and finishing for Gypsum Board Ceilings:
The following coat should be applied over the joints. a) First Coat or Jointing Coat b) Second Coat and c) Third Coat
First coat is primary jointing method where the fiber tape is fixed over the thin joining compound applied over the joints. Another layer of jointing compound of 75 mm wide fixing also to be done over the tape to cover Screw heads of ceiling. After dried these coats, the second and third coat should applied continuously. Each and every coat is to be feathered 50 mm outside the previous layer sides of the joint. Finally smooth sanding to be done and after drying it is ready for painting works.
After completion of taping, jointing, QA Engineer and site in charge should check the level and ensure, that is in true level and the work is within the acceptable limits.
Cleaning and Handover to the Painting works: After completion of all these activities, the area should thoroughly cleaned. Once the cleaning is done and approved by site in-charge a “Request for inspection” could be raised and after getting green signal from Project in charge, The area then would be handed to the painting and finishing works.
- Caution: The dust obtained from sanding at the joints should be removed either using soft cloth or soft broom before the commencement of painting works.
- Tip: Always use fisher plug with 35 mm long GI screws are recommended for perimeter channel fixing and black star screws of 25 mm for fixing Gypsum boards.
Health and safety Hazards:
All necessary safety measures using PPE’s, (such as nose mask, goggles, helmets, Hand gloves, shoes and safety belts ) ladder, scaffolding stand, platforms, first aid should be available at working place, have to be followed as applicable, and all the safety measures are covered separately in the Project Safety Plan.
Inspection methodology for Quality Inspection:
a. Check for alignment, level and verticality using the appropriate tools.
b. Ensure the joints are sunken by 4 mm to 5 mm at the joints to the width of the fibre mesh or paper tape
c. Ensure fibre-mesh or paper tape is fixed for all horizontal corners and joints.
d. Make sure all vertical joints are fixed with corner beads.
e. The Gap between two Gypsum boards should be restricted to or less than 5 mm.
f. Ensure horizontal bracings are provided for GI frame in partitions of more than 3 m height.
g. Ensure horizontal bracings are provided for GI channel frame in slim partitions or places where wall mounted fixtures, switch plates etc. are likely to be fixed.