A house is never explained by one sheet. Begin with the drawing index and separate architectural sheets (A), structural sheets (S), electrical sheets (E) and plumbing sheets (P). The title block identifies the project, sheet title, drawing number, scale, revision and issue date. Always use the latest revision cloud and revision register before measuring.
Read written dimensions before scaling a drawing. A 1:100 plan means 10 mm on paper represents 1 m on site; 1:50 means 20 mm represents 1 m. Never measure a screenshot or a print marked ‘not to scale’. Establish north, road level and the site benchmark before reading room positions.
Follow the information hierarchy: notes and dimensions override scaled measurement; enlarged details override general plans; the latest revision overrides earlier issues. Raise an RFI when two current drawings disagree rather than choosing the convenient answer.
1:100 scale
10 mm = 1 m
1:50 scale
20 mm = 1 m
1:20 detail
50 mm = 1 m
Common sheet prefixes
A · S · E · P
Remember on site
- Confirm drawing number, revision and issue date before every take-off.
- Use written dimensions; scale only when the drawing explicitly permits it.
- Architectural and structural sheets must be overlaid and cross-checked.
Check yourself
On a 1:100 plan, 10 mm on paper equals…
Two current drawings disagree. You should…
Where on a drawing sheet would you typically find the drawing number and revision?
What does 'GFC' commonly stand for on construction drawings?
A drawing scale of 1:50 means 1 unit on paper represents how much on site?
At a scale of 1:100, a line measuring 3 cm on the drawing represents what actual length?
Why is the north point symbol important on a floor plan?
What is the purpose of the legend or abbreviations key on a drawing sheet?
When comparing architectural and structural drawings of the same building, what should always match?
If two copies of the same drawing number have different revision letters, which one should be used for construction?
What is the risk of working from an outdated drawing revision on site?
A full architectural drawing set typically includes which combination of drawings?