Amogh N P
✦ In loving memory of Amogh N P — Architect · Designer · Visionary ✦
A precast concrete apartment building under assembly showing a clear repeating modular grid of identical wall panels and floor slabs being craned into place, the modular discipline made visible, no readable text.
Unit IIIIndustrial Architecture

Modular Coordination

The dimensional discipline that lets parts fit.

≈ 45 min + studio task

Prefabrication only works if the parts fit — and that needs a shared dimensional language. Learn modular coordination: designing to a basic module (internationally 100 mm, "M") and a grid of its multiples so components made separately fit without cutting; the advantages and limitations of the modular principle; the standardised components of a residential building; and the precast elements that populate a coordinated grid.

Learning objectives

By the end of this lesson, you will be able to — mapped to the course outcomes for Industrial Architecture:

1
CO3 · Understand

Explain modular coordination and the basic module.

2
CO3 · Analyse

Weigh the advantages and limitations of the modular principle.

3
CO3 · Understand

Identify the standardised components of a residential building.

4
CO3 · Understand

Recognise the common precast elements.

The basic module

The dimensional discipline

Modular coordination designs to a basic module (100 mm, "M") and a grid of its multiples, so separately-made parts coordinate without cutting; it brings standardisation, but risks rigidity and monotony.[1, 2]

Modular coordination component A B 1 module = 100 mm (M) Every part is a MULTIPLE of the basic module — so parts coordinate without cutting or packing. 'The module is the size of a room' is a myth — M (100 mm) is a small coordinating unit; parts are multiples of it.
DiagramModular coordination lays the building on a grid of the basic 100mm module so separately-made parts fit without cutting

A shared dimensional language

MODULAR COORDINATION is the dimensional discipline that lets prefabricated parts fit. It works from a BASIC MODULE — internationally the 100 mm module, written 'M' — and lays out the building on a GRID of its multiples (and sub-multiples for fine work). Every component is sized to the grid, so a slab, a panel and a column made separately all COORDINATE without cutting or packing. It is the same idea as a standard screw thread: agree the dimensions once, and parts become interchangeable. MISCONCEPTION→correct: 'the module is the size of a brick or a room' — the basic module (100 mm) is a small coordinating UNIT; rooms and components are multiples of it, not the module itself.[1, 2]

Order, at a price ADVANTAGES standardisation · interchangeable fewer sizes to make & stock faster design & manufacture fewer errors LIMITATIONS dimensional rigidity risk of monotony hard on irregular sites / curves Discipline at the dimensional level need not force monotony at the design level. 'Modular means boring' is a myth — good designers vary colour, depth and arrangement within the grid.
DiagramThe modular principle brings standardisation and interchangeability but risks dimensional rigidity and monotony
The repeated parts

Components & precast elements

A residential building is a few repeated components — frame or wall panels, slabs, partitions, stairs, service pods; and the precast family (columns, beams, hollow-core slabs, panels), often prestressed, is the workhorse of industrialised concrete building.[2, 4]

The precast family column beam hollow-core slab wall panel staircase 'Precast is only grey utilitarian' is a myth — finish, texture and colour can be cast into the mould.
DiagramThe precast family — columns, beams, hollow-core floor slabs, wall panels and staircases, the workhorse of industrialised concrete building

The repeated parts

A residential building, seen as a system, is made of a few REPEATED COMPONENTS: the structural FRAME (columns and beams) or load-bearing WALL PANELS, FLOOR / roof slabs, internal PARTITIONS, STAIRCASES, and service cores (often a prefabricated bathroom/kitchen 'pod'). Because a housing block stacks the same flat many times, these few components are made over and over — which is exactly what makes the factory worthwhile. Identifying the repeated component is the first design move in an industrialised housing project.[2]

Modular coordination

At a glance

AspectDetailNote
Basic module100 mm (M)The coordinating unit
Design sits onA grid of module multiplesParts coordinate by design
AdvantageStandardisation, interchangeFewer sizes, faster, fewer errors
LimitationRigidity, monotony riskVary within the grid to avoid it
Precast familyColumns, beams, slabs, panelsDesigned to the grid
Vocabulary

Key terms

Modular coordination

Designing to a shared dimensional grid so parts fit without cutting.

Basic module (M)

The coordinating unit — internationally 100 mm; components are multiples of it.

Planning grid

A grid of module multiples that the whole design and its parts sit on.

Interchangeability

Standardised parts that fit anywhere on the grid — the modular payoff.

Precast element

A component (column, beam, slab, panel) cast in a mould and lifted into place.

Prestressing

Tensioning steel before casting so a precast member spans further and slimmer.

Apply it

Studio task

Lay out a one-room-wide flat on a planning grid in multiples of the 100 mm module — pick sensible modular dimensions for the room, the door and the window so they all coordinate. Then list the precast elements you would use to build it, and say one thing you would do to keep a hundred of these flats from looking monotonous.

Check your understanding

Self-assessment

1. The internationally agreed basic module for modular coordination is —

2. The main payoff of modular coordination is —

3. 'Precast is only for grey utilitarian buildings' is —

In a nutshell

Recap

Modular coordination designs to a basic module (100 mm, 'M') and a grid of its multiples so parts fit without cutting.
It is like a standard thread — agree the dimensions once, and components become interchangeable.
Advantages: standardisation, fewer sizes, faster design and manufacture, fewer errors; limitations: rigidity and monotony risk.
A residential building is a few repeated components — frame or wall panels, slabs, partitions, stairs, service pods.
Precast elements (columns, beams, hollow-core slabs, panels), often prestressed, are the workhorse of industrialised concrete building.
The evidence

References & further reading

  1. [1]ISO modular coordination standards — the basic module (M = 100 mm) and the planning grid.
  2. [2]Henrik Nissen, Industrial Building and Modular Design — modular coordination and its trade-offs.
  3. [3]National Building Code of India — modular coordination and standardisation (relevant parts).
  4. [4]PCI / precast-concrete handbooks — precast and prestressed elements and connections.

Further reading

  • Henrik Nissen — Industrial Building and Modular Design.
  • Albert G. H. Dietz — Industrialized Building Systems for Housing (MIT).
  • Precast/Prestressed Concrete Institute (PCI) — Design Handbook.

Sources gathered and fact-checked June 2026. Published values vary by source, sample and method — treat as indicative and confirm against the cited standard before structural use.