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Enumerate the different types of specifications for items of construction works? Write the detailed specification for external plastering, 20mm thick CM (1:4)

Mumbai University > Civil Engineering > Sem 7 > Quantity Survey, Estimation and Valuation

Marks: 8M

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Types of Specifications:

a) General specification

b) Detailed specification

c) Standard specification

Detailed specification for external plastering, 20mm thick CM (1:4)

Preliminary

The work of sand faced cement plaster shall be carried out after masonry joints are raked out to a depth of 20 mm and the walls are well watered.

Procedure for First Coat

The first coat for sand faced cement plaster shall be of cement mortar in proportion 1:4 one part of cement to four Part of clean, coarse and angular river sand by volume. The mortar of one cement bag shall only be prepared at a time and it shall be prepared on a water tight platform or in a steel trough. The mortar shall be consumed within 30 minutes after adding water.

The first coat of plaster shall be uniformly applied in the best workmanship manner after watering the surface of walls in advance and putting dots and preparing screeds for maintaining uniform thickness of plastered surface.

The thickness of first coat shall be nowhere less than 12 mm, the first coat shall be well watered at least for 7 days. The first coat shall be provided with zigzag lines such that the first coat adheres well with the second coat.

Procedure for Second coat

The second coat of sand faced cement plaster shall be carried out in CM of proportion 1:1 and shall be of thickness 8mm. The second coat shall be applied on the first coat at least after 7 days of completion of first coat.

The second court shall give uniform grey colour to the whole structure or any other colour approved by the engineer. The sand to be used in the mortar for the second coat shall be perfectly screened so that sand of uniform size shall appear on the surface. The sponge shall be used in the second coat and it shall be applied when the second coat is wet and it shall be so worked that the density of the sand grains appearing on the surface shall be equal and uniform. After completion of the second coat, the surface shall be kept well-watered at least for 15 days

Measurement

The payment shall be made for superficial are covered.

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