Laying Out One A2 Sheet: Elevation Plus Site Plan
A second-year student must present one A2 sheet (420 mm × 594 mm) with a 20 mm margin all round, containing two drawings: the front elevation of a two-storey building 12.0 m wide and 9.0 m deep with a parapet, total height 7.5 m, and a site plan of the 40 m × 30 m plot on which it stands. A title block of 150 mm × 40 mm and a dimension zone of about 15 mm per side are also needed.
The studio convention is 1:50 for elevations and 1:100 for site plans. The student finds the layout will not close and proposes squeezing the elevation to 1:100 as well. A tutor objects that 'an elevation at 1:100 is unreadable'. The student has 40 minutes, one sheet, and no plotting machine, and must decide the sheet orientation, the scale of each drawing, and whether a mixed-scale sheet is acceptable.
1. Compute the drawn sizes at 1:50 and 1:100 and show, arithmetically, why the conventional layout fails on one A2 sheet.
Read the worked answer
Usable area. A2 = 420 × 594 mm; with a 20 mm margin all round the usable rectangle is 380 × 554 mm. Also set aside the title block (150 × 40 mm) and roughly 15 mm of dimension zone on each side, which brings the practical drawing area to about 350 × 524 mm - or, in landscape, 524 × 350 mm.
Drawn sizes.
- Elevation, 12.0 × 7.5 m at 1:50 → 240 × 150 mm.
- Elevation at 1:100 → 120 × 75 mm.
- Site plan, 40 × 30 m at 1:100 → 400 × 300 mm.
- Site plan at 1:150 → 267 × 200 mm.
- Site plan at 1:200 → 200 × 150 mm.
Why it fails. Portrait: the plan is 400 mm wide against 380 mm usable - it does not even fit alone, so the orientation is wrong from the start. Landscape: the plan's 400 × 300 mm fits, but it leaves only 350 − 300 = 50 mm of depth, and the 1:50 elevation needs 150 mm; stacking gives 300 + 150 = 450 mm against 350 mm usable, an overrun of 100 mm. Rotating or shifting does not help, because the total depth demanded is the sum of the two depths.
The failure is therefore not a tracing error but an arithmetic impossibility: at 1:50 and 1:100 the two drawings cannot coexist on A2 with title block and dimensions.
2. Recommend a sheet layout and scale combination that closes, and justify whether mixed scales are acceptable.
Read the worked answer
Best fit: landscape, plan at 1:150, elevation at 1:50. Depth 200 + 150 = 350 mm, exactly the usable depth; widths 267 mm and 240 mm against 524 mm, leaving about 250 mm beside the elevation for the 150 mm title block. This keeps the elevation at the scale the tutor wants, where material hatch, parapet coping and a 1:50 human figure (35 mm tall) actually read.
Fallback: plan at 1:200 (200 × 150 mm), giving 350 − 150 − 150 = 50 mm of slack and a standard scale that is certainly on the student's scale rule. At 1:200 a 40 m plot is 200 mm long, so setbacks of 3–6 m become 15–30 mm - still measurable, but coarse. Use 1:150 if the rule carries it, otherwise 1:200, and never invent a scale the rule cannot set out.
Reject: both at 1:100. It does close arithmetically (300 + 75 = 375 ≤ 380 mm), but it leaves 5 mm of slack for dimension lines, section markers and levels, and it produces a 120 × 75 mm elevation in which the parapet is under 1 mm thick. The tutor is right: that is not a drawing, it is a diagram.
Are mixed scales acceptable? Yes, provided they are unambiguous - each view labelled boldly ('SITE PLAN 1:150', 'ELEVATION 1:50'), and the plan carrying its own graphic scale bar so a reduced photocopy stays measurable. Mixed scales are normal practice; unlabelled mixed scales are the error. Finally, plot the title block and margin first, then place the largest drawing, then fit the second into what remains - the reverse order is what produced the dead end.