What bar size is used for columns in a G+1 house?

Commonly 12 mm to 20 mm main bars with 8 mm rings, but the correct sizes come from your engineer's design.

What size bar is used for a slab?

Usually 8 mm or 10 mm bars in a two way mesh, with spacing as per the design.

How do I find the weight of a bar?

kg per metre = d² / 162, where d is the diameter in mm. For example a 12 mm bar weighs 144 / 162, about 0.889 kg per metre.

How much steel does a G+1 house need in total?

As a rough thumb rule 3.5 to 4.5 kg per sq ft of built-up area. See our steel guide and calculator.

Steel for a G+1 house: typical column, beam and slab bar sizes

Consult your structural engineer first

The bar sizes, counts and spacing in a building depend on loads, spans, soil and seismic zone. Amroha is in seismic zone IV. These numbers are common ranges only and are not a design. Do not build from this page. Consult your structural engineer and follow the drawing.

Typical bar sizes by member

Commonly seen sizes in small G+1 houses, for orientation only
Member	Main bars	Stirrups or distribution
Column	12 mm to 20 mm, at least 4 bars	8 mm rings at close spacing
Beam	12 mm to 20 mm, top and bottom	8 mm stirrups
Slab	8 mm to 10 mm, two way mesh	Spacing set by the design
Footing	10 mm to 16 mm mesh	As per drawing

Heavier spans, taller columns or more floors need bigger bars or more of them.

IS 456 rules worth knowing

Longitudinal steel in a column must be between 0.8% and 6% of the column's gross cross section.
A rectangular column needs at least 4 bars, with a minimum bar diameter of 12 mm.
Lateral ties or stirrups should not be smaller than 6 mm or one quarter of the largest main bar.
Clear cover to steel is set by IS 456 for the exposure, and cover blocks keep it uniform.
In seismic zones IS 13920 adds closer stirrup spacing at beam and column joints and asks for ductile steel.

Weight per metre of common bars

Weight of a TMT bar in kg per metre is d²/162, where d is the diameter in mm. Use it to turn a bar schedule into tonnes for ordering.

Weight per metre by d²/162
Diameter (mm)	kg per metre	Approx. kg per 12 m bar
8	0.395	4.74
10	0.617	7.40
12	0.889	10.67
16	1.580	18.96
20	2.469	29.63

Order checks

Use Fe500D or Fe550D under IS 1786 for ductility in seismic zone IV.
Add wastage and lap lengths to the net bar schedule.
Store bars off the ground, covered, and sorted by diameter.

Frequently asked questions

What bar size is used for columns in a G+1 house?: Commonly 12 mm to 20 mm main bars with 8 mm rings, but the correct sizes come from your engineer's design.
What size bar is used for a slab?: Usually 8 mm or 10 mm bars in a two way mesh, with spacing as per the design.
How do I find the weight of a bar?: kg per metre = d² / 162, where d is the diameter in mm. For example a 12 mm bar weighs 144 / 162, about 0.889 kg per metre.
How much steel does a G+1 house need in total?: As a rough thumb rule 3.5 to 4.5 kg per sq ft of built-up area. See our steel guide and calculator.