Explanations:
The measurement is NOT made in square metres in case of R.C Chhajja, because thickness of its not negligible. Those quantities measured in different units are given below. Reinforced brickwork - cu.m Formwork - sq.m Reinforcement - quintal Damp proof course - sq.m Cement concrete grill work - sq.m Tiled roofing, A.C sheets , G.I sheets –sq.m