Measuring RCC for RA bills

Unit of measurement

Reinforced cement concrete (RCC) in slabs and beams is measured in cum. RCC is measured as the net volume of concrete to the drawing dimensions, member by member, with the steel paid separately by weight.

The BOQ item description decides the unit and what the rate includes. Where the BOQ and this guide differ, the BOQ and the contract's mode of measurement win.

What is measured

• Slabs: length and breadth between the faces of supporting beams or walls, times the slab thickness on the drawing.
• Beams: length between supports, times breadth, times depth below the slab, so the slab volume is not counted twice.
• Columns: cross-section times height from the top of the footing or floor to the underside of the slab.
• Grade of concrete and floor level, where the BOQ prices them separately.

Standard deductions

• Volume of reinforcement is not deducted; the steel is billed under its own item.
• Openings, ducts and cut-outs above the size set by the contract's mode of measurement and the relevant part of IS 1200 are deducted.
• Small chamfers, fillets and embedded conduits are commonly not deducted.

Worked example

Ward office building, RCC M25 in slabs and beams at floor five, BOQ item 3.2. Beam depth is taken below the slab.

Row by row: Slab S3, bay 2 to 4, 1 x 12.4 x 6.2 x 0.15 = 11.532; Beams B7 to B10, 4 x 6.2 x 0.25 x 0.3 = 1.860; Less duct opening, 1 x 1.2 x 0.9 x 0.15 = 0.162.

Total: 11.532 plus 1.860 minus 0.162 = 13.230 cum. Deductions are entered with negative nos, so they reduce the total in the same column.

Common disputes

• Beam depth is measured from the top of the slab, so the slab volume over the beam is billed twice.
• Slab thickness is claimed from an older drawing after a revision changed it.
• Openings for shafts and ducts are not deducted.
• Concrete in a member built larger than the drawing is claimed in full.

Recording it in Tatha Vastu

Each member is an entry against item 3.2 with the drawing number and revision. Deductions are their own rows, shown in red, and the client's engineer can open the entry from the abstract line in the bill room and see the drawing reference and the photo.

Approved entries are locked, and a correction becomes a new version with its reason. See the measurement book, or use the measurement sheet template if you still keep the register in Excel.