"0.4 bags per square foot" is the most quoted thumb rule in house construction. It is a reasonable starting point for an ordinary RCC-framed house with brick walls. Here is where it comes from and when it goes wrong.
Where the cement actually goes
In a typical G+1 house, cement is spread roughly like this:
- RCC work (footings, columns, beams, slabs): about 45%
- Plaster (internal 12 mm and external 18–20 mm): about 25%
- Brick masonry mortar (1:6): about 20%
- Flooring bed, PCC, DPC and miscellaneous: about 10%
Add these up for a normal layout and you land near 0.38–0.42 bags per sq.ft of built-up area. A 2,000 sq.ft house therefore needs around 800 bags.
When the thumb rule holds
- Framed structure with 9 in external and 4.5 in internal brick walls
- Normal soil with isolated footings
- Tiled floors on a cement bed
When it leaves you short
- Weak soil: a raft or deep footings can add 60–120 bags on their own.
- Many small rooms: more walls mean more mortar and double-sided plaster.
- Thick or textured external plaster, boundary walls, water tanks and septic tanks. These are all extra.
- Stone or granite flooring laid on a thicker mortar bed.
When it overestimates
AAC blocks laid with adhesive mortar, gypsum plaster inside, and large open-plan floors can bring consumption down to about 0.32–0.35 bags per sq.ft.
Buy in stages
Cement loses strength in storage, roughly 20% after three months even when stacked well. Order against the work schedule: foundation, then each floor's frame, then masonry and plaster. Store it on a raised platform covered with plastic sheet, never directly on the ground.
