# Column load takedown by hand, step by step

> How to take one column down by hand: tributary area per floor, load per floor, accumulate down the building, then factor. A full worked example with numbers.

**Category:** Load paths  
**Author:** Sam Rivera (Structural engineer · Educator)  
**Published:** 2026-05-10

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A column load takedown by hand is four moves repeated down the building: find the tributary area on each floor, turn it into a load, accumulate from the roof down, then factor the total. This page works one interior column on a six by five metre grid through three floors and a roof, so you can follow every number. StructLoads automates the same steps, but doing one by hand is the fastest way to understand what the tool is computing.

## Set up the column and its tributary area

Take an interior [column](https://en.wikipedia.org/wiki/Column) on a regular six by five metre grid carrying three suspended floors and a roof. An interior column draws a half bay on every side, so its tributary area is the full surrounding bay: 6 by 5, which is 30 square metres on every level. That single area is the geometric input for the whole takedown. The reasoning behind the full-bay rule is in [how to calculate tributary area for a column](/blogs/how-to-calculate-tributary-area-for-a-column).

## Step 1: load per floor

Multiply the tributary area by each floor [load](https://en.wikipedia.org/wiki/Structural_load) to get what the column collects on that level. With 4.5 kN per square metre of dead load and 3.0 kN per square metre of live load, each suspended floor gives 4.5 times 30, which is 135 kN of dead load, and 3.0 times 30, which is 90 kN of live load. The roof, at 3.8 kN per square metre dead and 1.0 kN per square metre roof load, gives 114 kN dead and 30 kN roof. Keep dead, live and roof in separate columns so the load factors can act on each later. If you need to build the floor pressure itself from the slab, finishes and services rather than assume it, [Ochshorn's dead loads chapter](https://jonochshorn.com/structuralelements/book/2.01-dead-loads.html) tabulates the unit weights that sum into that per-square-metre figure.

## Step 2: accumulate down

Walk down the column adding each floor to a running total. The reaction at the base of any storey is everything above it.

| At the base of | Cumulative dead (kN) | Cumulative live (kN) | Cumulative roof (kN) |
| --- | --- | --- | --- |
| Level 3 | 249 | 90 | 30 |
| Level 2 | 384 | 180 | 30 |
| Level 1 | 519 | 270 | 30 |

By the foundation the column holds 519 kN of dead load, 270 kN of live load and 30 kN of roof load, all unfactored. This is the same accumulation shown in full in [a floor-by-floor worked example](/blogs/load-takedown-worked-example).

## Step 3: factor the result

Service loads do not size members, so apply the governing [ASCE 7](https://www.asce.org/publications-and-news/asce-7) combination. The dead-only case gives 1.4 times 519, which is 727 kN. The live-leading case gives 1.2 times 519 plus 1.6 times 270 plus 0.5 times 30, which is 623 plus 432 plus 15, or 1070 kN. The live-leading combination governs, so the factored design reaction is about 1070 kN, the number that sizes the column and its footing. The wider method of choosing column sizes from this load is in [how to calculate column loads](/blogs/how-to-calculate-column-loads).

## How to check it by hand

Two quick checks confirm the result. First, the load per floor: 135 kN dead should equal the floor pressure times the area, 4.5 times 30, which it does. Second, the ratio check: an interior column should carry about twice an edge column and four times a corner on the same grid, so if a neighbour is wildly different, re-open the geometry. A third, building-wide check is that the sum of all column dead loads on a floor equals the floor dead pressure times the floor area.

## Key takeaways: a hand column takedown

Tributary area, load per floor, accumulate, factor: four moves, repeated down the column. The arithmetic is light once the 30 square metre area is set, which is why the geometry deserves the care. Doing it by hand makes the [full structural load takedown](/blogs/how-to-do-a-structural-load-takedown) legible, and it is a preliminary gravity figure that a qualified engineer confirms in detailed design.

## Quick answers

### How do you do a column load takedown by hand?
Find the column's tributary area on each floor, multiply by that floor's dead, live and roof loads to get the load per level, add the levels from the roof down to a running total, then apply a load combination for the factored reaction. On a regular grid the tributary area is the full bay for an interior column, so the arithmetic is quick once the geometry is set.

### What numbers do you need before you start?
You need the column's tributary area per floor, the dead, live and roof loads on each floor in kN per square metre, the number of levels the column carries, and the governing load combination. Slab self weight goes into the dead load. With those, every step is multiplication and addition; the only judgement is the tributary geometry.

### How do you accumulate loads down the column?
Start at the roof and keep a running total as you move down. At each floor, add that floor's load to the total already carried from above. The reaction at the base of any storey is everything stacked on it, so by the foundation the running total is the full column load, kept separate for dead, live and roof.

### When is a hand column takedown not enough?
It is a preliminary gravity figure. It is not enough once moments, lateral wind or seismic loads, slenderness, continuity or unequal spans matter, or when the column carries a transfer beam. Use the hand takedown to set the early size and check the gravity reaction, then move to full analysis, with a qualified engineer reviewing the design.