What is the rule for deduction in the measurement of plastering work?

Plastering deductions as per IS code 1200. For opening of size 0.5 m2 to 3 m2 area, deduction is made on one face of the wall. For openings of size above 3 m2, deduction is made on both faces of the wall, but the area of sill, jamb and soffits of the opening is added.

Length and height is measured correct to a centimeter of the wall before plastering. For openings upto 3 Sqm one side deduction is made on the reveal side and other side ignored. For openings larger than 3 Sqm both side shall be deducted and jambs to be mearured. In small openings and ends of beam /disimiilar components less than 0.5 Sqm is ignored. Thickness and mix gradation is indicated. ( 12 mm of mix 1:4).

Deduction in the measurement of plastering work :

As per my knowledge in civil engineering, I will be discussing here some points regarding the above concept, they are as follows;

1. Actually, no deduction shall be done for the ends of joist, beam, post, etc
2. The openings should not be exceeding than 0.5-metre square each
3. And most importantly no addition shall be made for reveals, jams, soffits and sill for this opening.
4. Deduction for opening exceeding than 0.5-metre square is O.K but not exceeding three-meter square each.
5. Whenever any two phases of the wall are plastered with the same plaster then deduction shall be made for one face only
6. When two phases of the wall are plastered with the different types of plaster then again deduction shall be made from the Plaster on the side on which the width of reveals is less than the width of the other side
7. When the width of reveal on both phases of the wall are equal deduction of 50% of the area of opening on each shall be made from areas of plaster

After looking at the above figure that I posted here, your knowledge regarding the given concept will get strong.

Thank you ask a question.

As per the mode of measurement I used in my earlier part of career , 50% of the opening size is deducted.

Hope this helps.