PART A: JOB PROCDRE FOR PLASTERING

Transcription

1 PART A: JOB PROCDRE FOR PLASTERING 1. SCOPE: The scope of this procedure shall apply to all cement plaster finishes to column, ceilings, walls and similar surfaces on backgrounds met with such as brick, stone or concrete carried out during the execution of the civil works at Loni terminal revamping project. 2. PURPOSE: The purpose of this procedure is to ensure the high quality of the plastering work executed and thus it shall meet all the requirements as per tender specifications and all relevant IS codes, and the finished structures have specified plastering thickness and perfect smooth surface without a cracks etc all complete. 3. CODES TO BE REFERRED IN CONJUNCTION WITH THIS DOCUMENT: IS 2250: 1981 CODE OF PRACTISE FOR PREPARATION AND USE OF MASONRY MORTAR 4. SURFACE PREPARATION PRIOR TO PLASTERING WORKS: Dust and loose mortar shall be brushed out. Efflorescence if any shall be removed by brushing and scraping.

2 The surface shall then be thoroughly washed with water, cleaned and kept wet before plastering is commenced. Concrete surface shall be roughened by wire brushing and all the resulting dust and loose particles cleaned off and care shall be taken that none of the retarders is left on the surface. 5. PLASTERING WORKS: Visual inspection, sieve analysis and carrying out of all field tests of sand as per attached specifications Verification of the test reports of all the tests of cement and sand specified in tender documents from govt. approved laboratory supplied by the contractor with respect to the specifications Temporary scaffolding and staging commonly of bamboo, timber or tubular steel having horizontal vertical and diagonal braces are to provided by the contractor. Single scaffolding shall not be used in important works. Scaffoldings shall be designed to withstand all the dead, live and impact loads which are likely to come on them and shall confirm to requirements of relevant building regulations and local building by laws. Ceiling plaster shall be first completed before commencement of wall plaster. Plastering shall be started from the top and worked down towards the floor. Plaster of about 15 x 15 cm shall be first applied horizontally and vertically, at 3 meters intervals over the entire surface to serve as

3 gauges with surfaces truly in the plane of the finished plaster surface. The mortar shall then be laid on the wall, between the gauges with trowel in a uniform manner slightly more than the specified thickness and brought to true surface by working a wooden straight edge. Finally the surface shall be finished off true with trowel or wooden float according to whether a smooth or a sandy granular texture is required. All comers, arises, angles and junctions shall be truly vertical or horizontal as the case may be and shall be carefully finished. Rounding or chamfering comers, arises, junctions, etc, shall be carried out with proper templates at required places without any extra payment. Plastering and finishing shall be completed within half an hour of adding water to the dry mortar. In suspending work at the end of the day the plaster shall be left out clean to line both horizontally and vertically and while recommencing the edge of the old work shall be scraped, cleaned and wetted to enable proper jointing. Curing shall be commenced as soon as the plaster has hardened sufficiently. Plaster shall be kept wet for a period of seven days.

4 NOTE1: For 20 m thick two coat plastering works, coarse sand shall be used for the 12 mm thick undercoat (first coat) and fine sand for the 8 mm thick finishing coat (second coat) unless otherwise specified. The surface of under coat shall be left rough and 2mm deep furrows shall be made with a scratching tool to form key for the finishing coat. The surface shall be kept wet till the finishing coat is applied. The finishing coat shall be applied after the undercoat has sufficiently set but not dried and in any case within 48 hours of laying the undercoat. The surface shall be finished with special rubbing by sponge pads and other tools recommended for cement plaster work to obtain a uniform textured surface. NOTE2: Ceiling plaster shall not be commenced until the slab above has been finished and centering has been removed. In the case of ceilings of roof slabs, plaster shall not commence until the terrace work has been completed. Concrete surfaces shall be hacked at spacing not more than 5cm centers and depth shall not be less than 3mm. Surface shall be well wetted before applying the plaster The average thickness of ceiling plaster shall not be less than 6mm.

5 1) SCOPE: PART B: JOB PROCEDURE FOR POINTING The scope of this procedure shall apply to all cement mortar pointing on brickwork and stone work. 2) CODES TO BE REFERRED IN CONJUNCTION WITH THIS DOCUMENT: IS 2250: 1981 CODE OF PRACTISE FOR PREPARATION AND USE OF MASONRY MORTAR 3) SURFACE PREPARATION PRIOR TO PLASTERING WORKS: The joints shall be raked out properly while the mortar is green. Efflorescence if any shall be removed by brushing and scraping. The surface shall be washed with water and kept wet before pointing is commenced. The joints shall be raked in such a fashion that the minimum depth of new mortar measured from either the sunk surface of the finished pointing or from the edge of the brick/stone shall not be less than l2mm. The mortar shall be pressed into the raked out joints with a pointing trowel according to the type of pointing required.

6 The pointing lines shall be truly horizontal and vertical except where the joints are slanting as in RR masonry. Lines of joints from different directions shall meet neatly at the junctions. The pointing shall be finished with proper tool as follows: a) Flush Pointing: The mortar shall be pressed into the joints and shall be finished off flush and level with the edges of bricks/stones. The edges shall be neatly trimmed with a trowel and a straight edge. b) Raised Pointing: Raised pointing shall project from the wall facing with its edges cut parallel so as to have a uniformly raised band with about 6mm projection and 10mm width. c) Sunk Pointing: The mortar shall be pressed into joints and the top of the horizontal joint shall then be neatly pressed back about 3mm or as directed with the pointing tool. The pointing shall be kept wet for about 7 days and during this period it shall be protected from all damages. 4) MEASUREMENTS OF PLASTERING POINTING: Length and breadth shall be measured correct to a cm and area shall be calculated in square meters up to two decimal places. The measurement of plaster shall be taken before the plastering is done. No deductions shall be made or extra paid for openings less

7 than 0.5 sqm. Openings more than 0.5 sqm shall be deducted but additional measurements shall be taken for jambs, sills and soffits. Skirting of the wall shall not be measured (if the skirting is of different finish)