Column grid basics: where columns go and how far they span

In an RCC frame, columns carry the weight of floors down to the foundation. Where you place them affects the cost, the room layout and the look of the house.

Where columns normally go

• At the outside corners of the building.
• Where walls meet (junctions and T-junctions).
• Along long walls, so that no beam spans too far.
• Beside the staircase and lift shaft.

Span and cost

A longer span between columns needs a deeper beam and more steel. Many residential buildings keep spans to around 12 to 15 ft in one direction, but the right value depends on the loads and the engineer's design. Moving a few columns on paper at the planning stage is cheap. Moving them after the foundation is cast is not.

Column size

Small low-rise houses often use columns such as 10 x 12 in or 12 x 15 in. Taller buildings need larger columns at the lower floors. The size follows the number of storeys, the span, and the concrete and steel grade, so it is the engineer who finalises it.

Hide columns in walls

Place columns so they sit inside walls or at corners. A column in the middle of a bedroom wastes space and spoils furniture layout. Aligned columns on every floor also give a cleaner load path.

Try a layout

The PlanCraft 3D planner can generate a column grid automatically at wall corners, wall junctions and where a span is longer than your limit. You can then move, delete or add columns and see the effect in 2D, 3D and in the cost estimate.

A generated grid is a planning aid only. It is not structural design. A licensed structural engineer must design and sign off the frame.

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