Below are the plastering tools or plastering equipment involved in Plaster works that should be arranged before starting the plastering works.
- Surveying Equipment
- Line dory
- Plumb bob
- Spirit level
- Mixture Plaster Machine
- Wheel Barrow
- Wood float
- Straight edge
- Steel Brush
- Aluminum Section
- Mobile scaffolds
SAFETY & HEALTH REQUIREMENTS
- All employees shall be provided with complete personal Protection equipment PPE.
- All employees shall attend Safety Induction and training Course to identify all Hazards associated with this work.
- All workers shall be provided with proper tools and equipment to execute the work safely.
- MSDS (material safety data sheet) shall be displayed at work location as appropriate.
- Ensure that material, samples and method Statement have been submitted and approved by the consultant.
- Ensure that plastering tools & accessories are approved.
- Ensure proper working platform and lighting arrangement provided.
- Surfaces to receive plastering shall be dry brushed to remove all loose particles, dust, laitance, efflorescence, etc. and any projecting fins on concrete surfaces shall be hacked off.
- Where surfaces are out of line, they shall be brought to level by hacking or dubbing out prior to commencement of finishing.
- All required openings for mechanical & electrical services, conduits pipes, plugs shall be installed and tested prior to plastering.
- Curing arrangements shall be provided for three days.
Surface Preparation and Installation of Plaster Accessories
- All surfaces to be plastered or rendered shall be sprayed with water, which shall be allowed to dry out before rush coat is applied.
- Masonry work applied with scratch coat prior to plastering.
- Concrete surfaces where plaster to be applied shall be made rough.
- All undercoats shall be scratched to form an adequate key for the next coat.
- Level Guides shall be provided up to required thickness.
- All junctions between different materials and also over the embedded conduits shall be reinforced with expanded metal which shall be plugged nailed or stapled as required at required interval.
- All horizontal and vertical and vertical external and internal angles of plastered walls shall be protected with galvanized metal corner beads and shall be securely plugged, nailed or stapled as required at proper intervals.
- Plastering accessories such as plaster stops shall be used where plastering terminates and is not covered by other finish at wall, ceiling, door, window frame junctions and to all wall openings and corners.
- Plastering shall proceed only when the masonry block works are completed.
Mixing of Rush Coat and Application
- Surface must be sound, clean dry and free from any materials which may impair the adhesion of Rush coat.
- Pre-wet & saturate the surface with potable water before applying rush coat.
- Thoroughly mix MP3 ( rush coat) with potable water at the rate of approx. 10L of water /50 Kg. bag using a plaster machine is adjusted to obtain the consistent mix of wet mortar.
- Mixing and application shall be done by mechanical mixer as approved by the material manufacturer.
- Mix each batch separately. Clean out mixer between the batches.
- Mix no more material than used within one hour.
- The wet mixed mortar is sprayed on the wall using the spray gun of the machine.
- Apply the Rush coat using spray gun on the prepared surface in One or two coats to obtain 2~5mm thick rough texture.
- Cure the applied Rush Coat with potable water for minimum of 3 days.
Mixing of Final Coat and Application
- Wet rush coat evenly just before application of finish coat.
- In application using spray machine water flow is adjusted to obtain the consistent mix of wet mortar. The wet mixed mortar is sprayed on the walls using the spray gun of the machine.
- In case of manual mixing thoroughly mix MP13 with potable water at the rate of approx. 7 L of water/50 kg bag using an electrical paddle mixer attachment. The wet mixed mortar is then applied on the walls using trowel. Any caked and set mortar should not be applied.
- Apply the MP13 directly over the concrete masonry block walls in single coat at internal areas (10-20mm) and in double coat at external areas (15-20mm).
- On the prepared internal/external concrete surfaces (cast-in-situ or precast) MP13 is applied in single coat (10-20mm).
- The plaster shall be applied to the required thickness and adequate drying time shall be allowed for each undercoat prior to the application of the following coat.
- Finish the render plaster to medium fine finish using plastic/wooden trowel. Over toweling and smoothing of the render/plaster surface to be avoided in the final finishing.
- Final coat should be made in a true plane using an Aluminum straight edge.
- All wall faces finish shall be made plane and true to line in all directions and that all angles are straight, true and plumb.
- Extra care shall be taken for plastering to be made neatly good up to wood frames, skirting and around pipes or fittings.
- Cure the applied MP13 with potable water for minimum of three days.
- During the application existing work will be protected against spillage, staining and other damages.
- On walls plaster work shall be terminated at 100 mm above false ceiling elevation.
- Ceiling surface shall be plastered with 10-12 mm thick.
- Plaster shall only be stopped at corner beads or plaster stops at an induced groove.
- Where plaster abuts any metal item which is set in the plaster and is flush with the finished plaster surface, provide raked ‘vee’ joint at junction or as directed by the consultant.
- Point up and finish surfaces around fixtures, outlet boxes, piping, fittings, tile and other work flush with adjacent plaster.
- Each coat of all plasterwork is to be maintained in a moist condition for at least three days after the plaster.
- Finished work will be protected during progress of plastering work.
- Defective work shall be removed and replaced with new.
- If plaster thickness more than 2 cm, than we have to do double coat application, first coat is applied as spatter coat of 8~10mm. Cure the first coat for min. 2 days before over coating.
- Ensure that metal lath is straight, secured to substrate joint and surface perimeter accessories are in place.
- 300mm wide strip metal lath centered over junctions of dissimilar backing materials and casing beads @ terminations of plaster finish shall be installed.
- Corner beads shall be in One length up to 3000mm and no length shall be less than 1800mm and has to set in order to form true arises and neat miters, secure at ends and not more that 300mm apart with galvanized staples, galvanized wire ties or concrete nails, staggered install at all vertical & horizontal plaster exterior corners and to provide corner beads extension slips where is required.
- Horizontal beads shall be level, vertical beads, plumb, straight and true, assuming proper plaster thickness.
- Plaster Stop shall be used where called for or as required to stop plaster surface against a dissimilar to form a neat and definite joint.
- Corner mesh shall be provided on all internal corners prior to plaster.
- At all control joint locations install back to back square nosed casing beads.
- Mock-up shall be provided showing the executions’ systematic of the works in order to obtain the final approval accordingly.
Cutting, Patching & Repairing
- Cut out & repair all damaged plaster and all fine cracks, pits, checks waves, blisters and other defects which in the opinion of the consultant will impair the appearance and the life and usefulness of the finish surfaces.
- All repairs shall be done by using approved material.
Plastering in Case Total Thickness is More Than 20mm
- The areas where plaster thickness is expected to exceed 20mm, a multiple coat of plaster must be applied in receding thickness. A base coat of 15-20mm thickness should be applied and cure it for two days. After the base course becomes hard and dry, then apply the second coat / final coat of plaster with a thickness of 10-15mm.
- Wherever thickness is 40mm, it can be applied in two coats (20mm first coat, 20 mm second coat.)
- If the expected thickness to exceed 40mm, fiber mesh reinforcement should be given after the second coat in wet condition. When the plaster is wet, fix the mesh. After two days of curing, final coat can be applied to achieve a maximum thickness of 60mm.
Testing of Plaster Materials
- Compressive strength and flexural strength for 7 and 28 days of plaster as per the relevant codes of practice. Pull off Test for Plaster will be done by third party.