Last edited 19 Oct 2020

Scale in the construction industry

In very general terms 'scale' refers to an item's size in relationship to something else. For example, the components of a building may be designed so they are at a human scale, ie they are comfortable to use, are functional and anthropometric, or manufacturing can be carried out at scale, rather than for one-offs..

Typically, architecture deals with different types of scale:

Human scale: The human interaction with environments based on physical dimensions, capabilities and limits. Buildings can be designed with greater or lesser adherence to the concepts of human scale depending on the concept and purpose of the building.
Intimate scale: This is a smaller, more personal scale.
Monumental scale: This is much larger than human scale and is intended to be impressive, e.g. public buildings, memorials, religious buildings, and so on.
Proportion: This refers to the relative size of parts of a whole, the relationship between two things of different size.

The term scale is also used to describe the relationship between a depiction of a building, object, area of land etc compared to its actual size. Depictions are typically drawings or physical models. Drawing accurately to scale, and being able to shift between scales, is a fundamental skill of architectural drawing and spatial design.

Scale drawings are used to illustrate items that it is not useful or convenient to draw at their actual size. In the construction industry, a range of scales are generally used depending on the nature of the drawing. For example:

A location plan at 1:1000.
A site plan at 1:200.
A floor plan at 1:100.
A room plan at 1:50.
A component drawing at 1:5.
An assembly drawing at 1:1.

The first number refers to the size of the depiction (such as a drawing or model), and the second number refers to the relative size of the actual item being depicted. So that on a scale of 1:5, the actual item is 5 times bigger than the depiction, whereas on a scale of 5:1, the item is 5 times smaller.

By referring to a drawing or model as being ‘to scale’, it means that every element of it is represented to the same proportion, i.e. with the same relationships as the physical thing, but it is reduced or increased in size by a certain amount.

Digital depictions such as building information models (BIM) of computer aided design (CAD) drawings are generally not considered to be at a specific scale, that is, whist the relative proportions are correct, the user can zoom in or out and print drawings at whatever scale is required.

NB The Town and Country Planning (Development Management Procedure) (England) Order 2015 defines scale as: ‘the height, width and length of each building proposed within the development in relation to its surroundings.’