Concepts: Rules for deductions in plastering work are: 1. No deductions shall be made for opening or end steel joints, beams, post girders etc. up to 0.5 Sqm area. No addition shall be made for joints, soffits and sills of such openings. This is applicable to both the sides of the wall. 2. Where, opening exceeds 0.5 Sqm but does not exceed 3 Sqm and also when only one side of the wall is treated and other side is not treated, deduction shall be made if the width of the reveal on the treated sides is less than that on the untreated side but if the width of the reveal is more, then no deduction nor addition shall be made for reveals for jambs, soffits, sills etc. 3. For openings more than 0.5 Sqm but not exceeding 3 Sqm and also when both the sides of the wall is plastered with the similar plaster, deduction shall be made for one face only. But when both the sides treated with different plaster, then deduction shall be made from the side on which the reveal is less and no deduction on the other side. 4. For openings whose respective areas exceed 3 Sqm deductions shall be made for the full opening of the wall treatment on both faces while at the same time jambs, sills and soffits shall be measured in Sqm for payment. In measuring the jambs deduction shall not be made for the area in contact with the frames of doors, windows etc. 5. If the average thickness of the plaster is more than the specified thickness due to any account nothing extra shall be paid.