Common Metric Structural Scales and Applications
Written by Allan – February 2005
Selecting the correct scale is important because it permits easy and clear interpretation of the information shown. With uniform scales, elements appear in proportion. Seasoned plan readers are familiar with standard scales and can visualize the size quickly. Details can be standardized because of uniform text heights and be used from one project to the next.
Methods of indicating scales
Scales can be indicated by one of the follow:
- Add a scale bar on the drawing. No matter what scale is printed, a measurement on the drawing can be compared to the scale bar to derive the ‘real world’ units.
- A ratio prefixed by SCALE for example SCALE 1:100. This can be either in the title block or under the detail title, for example:
LEVEL 1 PLAN
SCALE 1:100
- If no scale is used the words NOT TO SCALE should appear in the title block.
- If a horizontal and vertical scales differ, prefix the ratio with HORZITONAL SCALE and VERTICAL SCALE.
| Scale | Common Uses |
| 1:100 | General plans scale, structural steel stick plans and elevations, concrete outlines. |
| 1:50 | Overall structural sections (not heavy on details), masonry wall elevations. |
| 1:20 | Concrete details and sections, retaining wall details, concrete block details, clay brick details. |
| 1:10 | Structural steel details and sections, precast details, timber details. |