Final Measurement Dispute on Brickwork
A contractor claims payment for 230 mm brickwork in a single-storey workshop. The wall is 20.0 m long and 3.2 m high, measured between column faces. There are two doors of 1.0 m x 2.1 m and three windows of 1.2 m x 1.2 m. The contractor measured the full wall volume and added 5% for wastage, claiming 14.72 m³ plus wastage, but the client's engineer says openings must be deducted and no wastage is payable. The accepted mortar is 1:6 cement mortar, bricks are modular 190 x 90 x 90 mm with 10 mm joints, and the contractor must submit a cement and sand requirement using 50 kg cement bags. A previous verbal agreement allowed 3% wastage on bricks only, not on mortar or measured volume. The rate is per cubic metre of finished brickwork.
1. Calculate the net measured volume and the number of bricks including the agreed wastage. State the measurement rules you applied.
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The gross wall volume is 20.0 x 3.2 x 0.23 = 14.72 m³. The two doors deduct 2 x 1.0 x 2.1 x 0.23 = 0.966 m³. The three windows deduct 3 x 1.2 x 1.2 x 0.23 = 0.9936 m³. The net volume is 14.72 - 0.966 - 0.9936 = 12.7604 m³, say 12.76 m³.
Openings larger than 0.1 m² are deducted; these doors and windows are larger. No deduction is made for mortar joints because the rate is per cubic metre of finished brickwork. With 10 mm joints, the nominal brick size is 0.20 x 0.10 x 0.10 = 0.002 m³, so there are 500 bricks per m³. For 12.7604 m³ the brick count is 12.7604 x 500 = 6380.2, say 6380 bricks. The agreed 3% wastage on bricks only gives 6380 x 1.03 = 6571.4, say 6572 bricks. The contractor's 14.72 m³ and 5% on the measured volume are both incorrect.
2. Calculate the cement and sand required for the 1:6 mortar, stating your assumptions and whether mortar wastage applies.
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The actual volume of bricks per m³ of masonry is 500 x 0.19 x 0.09 x 0.09 = 0.7695 m³, so the wet mortar volume is 1 - 0.7695 = 0.2305 m³ per m³ of brickwork. For 12.7604 m³, the wet mortar volume is 12.7604 x 0.2305 = 2.941 m³. Using a dry-volume factor of 1.33, the dry mortar volume is 2.941 x 1.33 = 3.912 m³.
For a 1:6 mix, the total parts are 7. Cement volume is 3.912 / 7 = 0.559 m³. At about 0.035 m³ per 50 kg bag, this is 0.559 / 0.035 = 15.97, say 16 bags. Sand volume is 3.912 x 6 / 7 = 3.353 m³, say 3.35 m³. Under the verbal agreement, wastage is allowed only on bricks, not on mortar, so no additional mortar wastage is included. If site practice requires mortar wastage, it must be agreed in writing before adding it.
3. How would you resolve the measurement dispute, and what records should support the payment?
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The dispute should be resolved by a joint remeasurement against the approved drawing, not by accepting either party's arithmetic. The measurement should apply the accepted rule that openings over 0.1 m² are deducted, and that the rate is for finished brickwork, so no volume is added for mortar joints. The verbal 3% brick wastage agreement should be confirmed in writing, including that it applies only to bricks.
The supporting records should include the approved drawing and revision, a signed joint measurement sheet with dimensions and opening sizes, the opening schedule, brick test and approval records, the mortar mix record, cement delivery challans, and the daily site diary. Photographs of the wall before plastering are useful. Payment should be certified on the net measured quantity of 12.7604 m³, with brick wastage shown separately as an agreed addition. Any disputed mortar wastage should be held back until it is formally agreed.