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Construction Drawing Practices Flashcards

Learn essential construction drawing conventions, line types, scales, symbols, and projection methods for accurate building documentation.

28 cards~10 min
Construction Drawing Practices Flashcards — Qwi
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1What is the purpose of a construction drawing?
Answer

To show shape, size, position and material composition of a building.

Construction drawings present precise, unambiguous information so anyone with draughtsmanship knowledge can understand how the building is to be constructed.
2The border of a drawing should be drawn {{10 mm}} wide around the paper edges.
Answer

10 mm

3Construction lines are drawn heavier than final lines.
Answer

False

Construction lines are light guide lines that are later covered by stronger final lines.
4How do thick active lines differ from thin active lines?
Answer

Thick active lines show important structural faces | Thin active lines show plan‑view items and less important sections

Thick active lines indicate outside/inside faces of walls and concrete members, while thin active lines are used for plan views and less critical details.
5Which scales are suitable for a floor plan of a building?
Answer

1:50 and 1:100

Both scales provide enough detail for architectural and structural layouts of floor plans.
6A 1:{{200}} scale is typically used for a site plan of a small building project.
Answer

200

7Lettering on construction drawings should always be done in lower‑case letters.
Answer

False

Capital letters are recommended for both notes and titles because they are easier to read.
8What does the abbreviation “NTS” indicate on a dimension?
Answer

Not to scale

When a dimension is not drawn to scale, “NTS” is added after the measurement.
9First‑angle projection vs. third‑angle projection: how are they identified on a drawing?
Answer

First‑angle uses a symbol with the plan on the left and elevation on the right | Third‑angle uses a symbol with the plan on the right and elevation on the left

The projection symbol printed on the drawing indicates which system is used; the arrangement of views differs between the two.
10What angle do the three faces form in an isometric projection?
Answer

120°

Isometric projection uses three equal angles of 120° between the three faces.
11In isometric projection, lines are shortened to {{82 %}} of their true length.
Answer

82 %

12In a one‑point perspective, all horizontal lines converge to a single vanishing point.
Answer

False

Only the lines not parallel to the picture plane converge; vertical lines remain vertical.
13What distinguishes a cavalier oblique from a cabinet oblique?
Answer

Cavalier uses true length on receding axes; cabinet reduces them to half length.

In a cavalier oblique, measurements along the receding axes are full scale, whereas in a cabinet oblique they are reduced to 50 % of true length.
14A {{grid}} is used to relate sizes and locations of building components in drawings.
Answer

grid

15What information does a site plan provide?
Answer

General shape, building locations, levels, surface features, and external services.

A site plan gives a bird’s‑eye view of the entire site, showing layout, levels, and services such as drainage.
16Floor plan vs. elevation: what dimensions are taken from each?
Answer

Floor plan provides horizontal dimensions | Elevation provides vertical dimensions

Horizontal dimensions are measured from plans, while vertical dimensions are taken from sections and elevations.
17How are doors indicated on plans regarding their opening method?
Answer

Standard symbols show swing or sliding doors and the direction of opening.

Door symbols differentiate between swing and sliding doors and include arrows indicating the opening direction.
18In a section view, the cutting plane is always horizontal.
Answer

False

Sections are usually vertical cuts, showing a vertical view of the building.
19The abbreviation {{R‑mild}} refers to mild steel round bars in reinforcement drawings.
Answer

R‑mild

20What does the reinforcement notation “21T10‑10‑200T1” indicate?
Answer

21 high‑tensile bars, 10 mm diameter, spaced 200 mm, placed near the top face.

The code shows quantity, type, size, spacing, and location (top face) of the reinforcement.
21Difference between a component drawing and an assembly drawing?
Answer

Component drawing details a single item | Assembly drawing shows how multiple items fit together

Component drawings focus on one part’s shape and manufacture, while assembly drawings illustrate the relationships among several components.
22What is the purpose of a freehand sketch in construction drawing?
Answer

To quickly record or explain existing structures or preliminary design ideas.

Freehand sketches can capture observations, clarify on‑site details, or serve as presentation drawings with advanced techniques.
23When drawing circles freehand, you should first draw the axes and mark the crossing points.
Answer

True

The axes help locate the centre and ensure accurate placement of the circle.
24The standard line thickness for a {{border}} is 10 mm.
Answer

border

25Which equipment is used to draw 0.3 mm thick lines?
Answer

A technical pen with a 0.3 mm tip.

The drawing set includes two technical pens: one for 0.3 mm lines and another for 0.7 mm lines.
26How do hidden lines differ from centre lines?
Answer

Hidden lines are broken to show invisible features | Centre lines are thin chain‑dotted to indicate the centre of objects

Hidden lines represent elements not visible in the view, while centre lines locate the midpoint of components such as beams.
27In orthographic projection, a third‑angle view places the plan above the elevation.
Answer

True

Third‑angle projection arranges the plan on top of the elevation in the symbol.
28What is the recommended practice for lettering guide lines?
Answer

Draw light upper and lower guide lines and write letters between them.

Guide lines should be faint so they remain visible but do not interfere with the final lettering.

Purpose of Construction Drawings

Construction drawings convey the shape, size, position, and material composition of a building. They provide precise, unambiguous information so that anyone with draughtsmanship knowledge can understand how the building is to be constructed.

General Layout and Borders

The drawing border frames the sheet and should be drawn 10 mm wide around the paper edges. This border defines the usable area and ensures consistency across all sheets.

Line Types and Their Uses

Active Lines

Active lines are the primary visual elements of a drawing. They appear in two thicknesses:

  • Thick active lines show important structural faces, such as the outside and inside faces of walls and concrete members.
  • Thin active lines are used for plan‑view items and less critical sections, providing a lighter visual weight.

Guide and Construction Lines

Construction (guide) lines are light, temporary lines that help position final geometry. They are lighter than final lines and are later covered by stronger lines.

Hidden and Centre Lines

Hidden lines are broken to represent features that are not visible in the current view, while centre lines are thin chain‑dotted lines that indicate the centre of objects such as beams.

Scales for Different Views

Choosing an appropriate scale ensures that details are legible while fitting the sheet size.

  • Floor plans of a building typically use 1:50 or 1:100 scales.
  • Site plans for small building projects commonly employ a 1:200 scale.

Lettering Conventions

Lettering should be done in capital letters for both notes and titles because capitals are easier to read. When lettering, draw faint upper and lower guide lines and write the characters between them.

Dimension Annotations

If a dimension is not drawn to scale, the abbreviation “NTS” (Not to Scale) is added after the measurement.

Projection Systems

First‑Angle vs. Third‑Angle

The projection symbol on a drawing indicates the system used:

  • First‑angle projection places the plan on the left and the elevation on the right.
  • Third‑angle projection places the plan on the right and the elevation on the left; in the symbol, the plan appears above the elevation.

Isometric Projection

Isometric drawings use three equal angles of 120° between the three faces. Lines are shortened to 82 % of their true length to represent depth.

Oblique Projections

Two common oblique types differ in how receding axes are represented:

  • Cavalier oblique retains true length on receding axes.
  • Cabinet oblique reduces receding axes to 50 % of true length.

One‑Point Perspective

In a one‑point perspective, only lines that are not parallel to the picture plane converge to a single vanishing point; vertical lines remain vertical.

Section and Elevation Views

Horizontal dimensions are taken from floor plans, while vertical dimensions are obtained from sections and elevations. Sections are usually vertical cuts, providing a vertical view of the building, not a horizontal cut.

Symbols for Building Elements

Doors

Standard door symbols indicate the type (swing or sliding) and the direction of opening with arrows.

Grids

A grid is used to relate sizes and locations of building components across drawings, acting as a reference framework.

Reinforcement Notation

In reinforcement drawings, the abbreviation R‑mild denotes mild steel round bars. A code such as 21T10‑10‑200T1 conveys:

  • Quantity: 21 bars
  • Type: high‑tensile (T)
  • Diameter: 10 mm
  • Spacing: 200 mm
  • Location: near the top face (T1)

Component vs. Assembly Drawings

Component drawings detail a single item, focusing on its shape and manufacturing requirements. Assembly drawings illustrate how multiple components fit together, showing relationships and connections.

Freehand Sketches

Freehand sketches are valuable for quickly recording or explaining existing structures or preliminary design ideas. When drawing circles freehand, start by drawing the axes and marking the crossing points; these axes help locate the centre and ensure accurate placement.

Equipment for Line Work

Technical pens are used to achieve consistent line thicknesses. A pen with a 0.3 mm tip draws fine lines, while a 0.7 mm tip is used for thicker lines.

Best Practices Summary

  1. Maintain a 10 mm border around the sheet.
  2. Use thick active lines for major structural faces and thin active lines for plan‑view details.
  3. Apply appropriate scales: 1:50 or 1:100 for floor plans, 1:200 for site plans.
  4. Letter in capital letters, guided by faint upper and lower lines.
  5. Mark non‑scaled dimensions with “NTS”.
  6. Identify projection type with the correct symbol and view arrangement.
  7. Remember isometric angles of 120° and the 82 % reduction factor.
  8. Distinguish cavalier and cabinet obliques by their scaling of receding axes.
  9. Use vertical sections for vertical cuts, not horizontal.
  10. Apply standard symbols for doors, grids, and reinforcement.
  11. Choose the correct technical pen for line thickness.