Concrete work for thin building elements of specified thickness is usually measured in square metres (area). Which of the following are measured in sq.m under this rule?

Introduction / Context:
In quantity surveying, the unit of measurement depends on the nature of work. Thin concrete layers or panels of specified thickness are typically measured by area, while structural concrete members (beams, slabs of structural thickness) are measured by volume. Recognizing this distinction is necessary for accurate billing.

Given Data / Assumptions:

• The items listed are thin elements with a stated uniform thickness.
• Measurement rules prescribe sq.m for such items.
• Formwork and reinforcement, if any, are measured separately in appropriate units.

Concept / Approach:
Concrete flooring, thin roof toppings, D.P.C. bands, and thin wall panels are all quantified by area because thickness is standardized in the specification; pricing reflects cost per sq.m for the given thickness and surface finish.

Step-by-Step Solution:
Roof/floor thin concrete: measured in sq.m at given thickness.D.P.C.: a thin band → measured in sq.m.Wall panels (thin): measured in sq.m.Therefore, “All the above” is correct.

Verification / Alternative check:
Standard schedules list concrete flooring and D.P.C. items on an area basis, with thickness embedded in the item description.

Why Other Options Are Wrong:

• Any subset misses at least one thin element that is indeed measured by area.

Common Pitfalls:
Confusing structural RCC slabs (measured in cu.m) with thin toppings/flooring measured in sq.m; not accounting for surface finish requirements in the specification.

Final Answer:
All the above.