Architectural Plans, Elevations and Sections

Introduction

Architectural drawing converts a building concept into coordinated information that can be understood and constructed by different members of a project team. A floor plan explains the horizontal arrangement of spaces; an elevation communicates the external appearance and vertical levels; a section reveals the relationship between foundations, floors, walls, roof and internal spaces. A reflected ceiling plan (RCP) records ceiling patterns, heights and services when these cannot be adequately shown on the floor plan.

For a civil draftsman, the principal professional task is not merely to draw attractive views. It is to produce a consistent set of drawings in which dimensions, openings, levels, materials, annotations and references agree. A door shown in plan must occur at the same position in the relevant elevation and section. A stair must rise between the levels shown in the section. A roof plan must correspond with the walls and drainage shown in plan and elevation.

This chapter presents the principles and workflow used to prepare coordinated architectural drawings in CAD. Local building regulations, office standards and project specifications always take precedence over examples in this chapter.

Learning objectives

After studying this chapter, the learner should be able to:

1. Explain the purpose and conventions of plans, elevations, sections and reflected ceiling plans.
2. Select suitable scales, line weights, symbols and annotation systems.
3. Produce coordinated floor, roof and ceiling plans.
4. Draw elevations and sections that communicate construction, levels and finishes.
5. Dimension and schedule openings, rooms, finishes and building components.
6. Check a drawing set for geometric, dimensional and technical consistency.
7. Apply a professional CAD workflow using layers, blocks, references and revision control.

1. The drawing set as a coordinated model

An architectural drawing set is a two-dimensional representation of a three-dimensional building. Each view is produced by imagining a different cutting plane or direction of projection.

• Plan: a horizontal cut, conventionally about 1.0–1.2 m above the finished floor, looking downward. The exact cutting height depends on the purpose of the drawing.
• Elevation: an orthographic vertical view of one external or internal face.
• Section: a vertical cut through the building, looking in a selected direction.
• Roof plan: a view of the roof from above, showing slopes, ridges, valleys, edges, drainage and roof penetrations.
• Reflected ceiling plan: a ceiling view represented as if the ceiling were reflected onto the floor plane. It shows ceiling construction, bulkheads, lights, diffusers, fans and access panels.

These drawings are complementary rather than interchangeable. A plan is strongest for horizontal location, an elevation for appearance and a section for vertical construction. Important information should not be forced into an unsuitable view.

Figure: The complementary purpose of plan, elevation and section drawings.

2. Graphic conventions and information hierarchy

Drawing conventions allow information to be interpreted quickly. A typical hierarchy is as follows, although the office or authority standard governs the final values.

Line-weight contrast is more important than using many line weights. A wall cut in plan should generally read more strongly than a cabinet, hatch or dimension. Text must remain legible at the printed scale; notes that are readable only when zoomed in are not professionally useful.

Common symbols include door swings, window markers, level markers, north arrows, grid bubbles, section arrows, elevation tags, material hatches and break lines. Symbols should be created as CAD blocks with consistent insertion points and attributes where schedules are required.

3. Floor plans

3.1 Setting out the plan

Begin with a controlled origin, structural grid or survey reference. Establish external wall faces, grid intersections and major dimensions before drawing internal partitions. This prevents accumulated errors caused by dimensioning each room independently.

A floor plan should normally include:

• external and internal walls;
• columns, beams or structural features that affect space;
• doors, windows and opening directions;
• stairs, ramps and changes in level;
• fixtures and equipment where relevant;
• room names and numbers;
• floor finishes or finish codes;
• grids, north arrow and drawing references;
• overall, setting-out and opening dimensions;
• notes concerning fire, accessibility or construction where required.

Wall thickness must represent the proposed construction, not simply a graphic strip. For example, a cavity wall may be represented by outer masonry, cavity, insulation and inner lining, whereas a lightweight partition may be represented by framing and board layers. The drawing scale determines how much material detail is shown.

3.2 Openings and circulation

Doors are drawn with the leaf, frame and swing where appropriate. The swing indicates the direction of operation and assists clearance checks. Door numbers should match the door schedule. Window tags should match the window schedule and elevation locations.

Circulation must be tested rather than assumed. Check clear widths, turning spaces, stair landings, door conflicts and accessible routes against the applicable regulations. Furniture may be included to demonstrate function, but it must be distinguished from construction elements.

3.3 Dimensions

A useful dimension system commonly contains three levels:

1. Overall dimensions: total building length and width.
2. Setting-out dimensions: grid lines, wall faces and major structural positions.
3. Detail dimensions: openings, piers, recesses, fixtures and local construction.

Avoid repeated or conflicting dimensions. Dimensions should normally be placed outside the plan, with extension lines aligned to the feature being measured. Internal dimensions may be used where external space is limited or where room sizes are important.

Dimensions should state the unit convention in the title block or notes. In a metric drawing, dimensions may be expressed in millimetres without repeatedly writing “mm”; the convention must be unambiguous. Do not mix nominal and actual sizes without identifying the distinction.

4. Roof plans

A roof plan is not simply an enlarged outline of the upper floor. It records the geometry and drainage logic of the roof. Show:

• roof perimeter, parapets and eaves;
• ridges, hips, valleys and roof planes;
• falls or slopes, with direction arrows where needed;
• gutters, outlets, downpipes and overflow provisions;
• roof lights, plant, vents and penetrations;
• access hatches and maintenance paths;
• roof material or construction codes;
• high and low points and relevant levels.

A roof plan must be coordinated with elevations. Eaves height, parapet height and ridge position should agree with the vertical drawings. Downpipes should discharge to a credible drainage system, not terminate in an unshown location.

Where a roof slope is given as a ratio, state the convention clearly. For example, a slope of 1:20 may mean 1 unit vertical rise for 20 units horizontal run; local standards may use percentage or degrees instead. The gradient is calculated as:

where g is the gradient, v is vertical rise and h is horizontal run, using the same units. The percentage gradient is 100g%. This relationship applies to a straight, uniform slope; complex roofs require separate assessment of each plane.

5. Reflected ceiling plans

The RCP is viewed from below, as though the ceiling surface were reflected onto the plan. It should identify ceiling heights, ceiling materials, bulkheads, access panels and visible services. Coordinate light fittings, smoke detectors, sprinklers, air grilles, diffusers, speakers and inspection hatches with structural and mechanical layouts.

A ceiling grid should not be drawn merely as decoration. Its module must fit the room boundaries and avoid unexplained fragments. Ceiling tags can identify finish and height, for example “CL-01, 2700 AFFL.” The abbreviation AFFL means above finished floor level, but the project standard should define all abbreviations.

The RCP must be checked against the floor plan: lights should occur in plausible rooms, bulkheads should correspond with walls or services, and ceiling changes should be visible in sections and elevations where they affect the external or internal appearance.

6. Elevations

Elevations are orthographic views of the building exterior or interior. Name them by direction or orientation, such as North Elevation, rather than relying only on sheet position. A complete elevation may show:

• ground line and finished floor levels;
• wall materials and joints;
• openings, frames, sills and heads;
• roof profile, eaves and parapets;
• balconies, stairs, ramps and external equipment;
• external finishes, colours or material codes;
• vertical dimensions and key levels;
• datum, grid and reference markers.

An elevation should not imply unsupported detail. If a hidden roof form or concealed structural element is important, use a section or suitable dashed convention. Material hatches and textures must remain controlled; excessive rendering can obscure technical information.

Openings require careful coordination. Window head and sill levels should match the section and window schedule. Door heights, transoms, shading devices and external steps should agree with the plan. The elevation is also a useful visual check: inconsistent sill heights, misaligned openings or unexplained changes in material often reveal errors in the plan.

7. Sections and vertical coordination

Select sections through locations that explain the building: a stair, major change in level, wet area, structural junction, roof edge or important spatial relationship. Mark the cutting line on the plan with arrows indicating the viewing direction and a reference such as A–A.

A section should communicate:

• foundations and ground relationship;
• ground, intermediate and roof floors;
• wall build-ups and structural supports;
• floor, ceiling and roof construction;
• stairs, landings and headroom;
• damp-proofing, insulation and waterproofing where relevant;
• finished levels and vertical dimensions;
• materials and construction references.

Elements cut by the section plane are shown heavily; elements beyond are lighter. Use poche or hatching selectively to distinguish concrete, masonry, insulation, earth and timber according to the office standard. A section is most valuable when it answers a construction question, not when it merely repeats an elevation.

Stairs

A stair must be represented consistently in plan and section. In plan, show the flight direction, nosings, handrails, landings and break line. In section, show risers, treads, landings, headroom and floor-to-floor relationship. The number and size of risers must be checked against local regulations.

For a stair with total vertical rise H, number of risers n, and riser height r, the relationship is:

If a flight has n risers, the number of treads depends on the stair arrangement and landing configuration; it must not be assumed automatically. A common comfort check uses 2r + t, where t is the going or tread depth. This is a design guideline, not a universal legal requirement, and the applicable code controls.

Illustrative example. A floor-to-floor height is 2,800 mm. If 16 risers are proposed, r = 2800 ÷ 16 = 175 mm. If 17 risers are used, r ≈ 164.7 mm. The acceptable choice depends on the governing code, available stair length, landing arrangement and comfort criteria. The draftsman must record the selected arrangement and check it against the approved design rather than selecting solely by arithmetic.

Levels and datums

Use a common vertical datum, such as a project benchmark or finished ground-floor level. Typical labels include FFL (finished floor level), SSL (structural slab level), TOS (top of slab) and RL (reduced level), but abbreviations must be defined. Never place an unexplained level value on one drawing and a different value on another.

A vertical dimension is meaningful only when its reference surfaces are clear. State whether a height is measured to structural slab, finished floor, ceiling, roof membrane or parapet top.

8. Finishes, schedules and construction information

Schedules reduce repetition and improve coordination. Typical schedules include doors, windows, rooms, finishes and fixtures.

A schedule must not become a second, contradictory design. Each tag should occur once or have a clearly defined repeated use. If a door is changed from a single to a double leaf, update the plan, elevation, schedule and any hardware or accessibility notes.

Finish plans can use codes such as FL-01, WL-02 and CL-01. The code should lead to a specification or finish legend. Hatching alone is insufficient where performance, fire rating, slip resistance or acoustic requirements are relevant.

9. CAD production workflow

A reliable CAD workflow is structured and repeatable:

1. Review the brief, survey, consultant information, regulations and office template.
2. Establish units, drawing limits, origin, coordinate system, layers and text styles.
3. Create grids, datums and reference geometry.
4. Draw walls and structural elements, then openings and stairs.
5. Add roofs, ceilings, fixtures, annotations and dimensions.
6. Generate elevations and sections from coordinated geometry or carefully controlled references.
7. Add schedules, legends, notes, title block, scale and revision information.
8. Plot a test sheet and inspect at the intended printed scale.
9. Perform geometric, dimensional, annotation and regulatory checks.
10. Issue a controlled PDF and archive the native CAD files according to the project procedure.

Use external references when multiple disciplines or team members work on a project. Use layers by function, such as walls, doors, windows, dimensions, text, furniture, ceiling and references. Layer names, colours and plot styles should be documented. Blocks should be used for repeated symbols, but avoid overusing blocks that conceal important editable geometry.

Parametric constraints, associative dimensions and model-based generation can reduce coordination errors, but they do not replace professional checking. A generated elevation may still omit a finish, misinterpret a cut plane or display an incorrect level.

10. Quality assurance and common errors

A drawing review should be systematic. Check the following:

• Do external dimensions equal the sum of internal dimensions and wall thicknesses?
• Do door and window tags match schedules?
• Do all openings shown in plan appear in the correct elevation?
• Do section markers point in the intended direction?
• Do floor, ceiling, roof and parapet levels agree?
• Does the stair connect the stated floors and provide required headroom?
• Are roof falls, gutters and downpipes logically complete?
• Are dimensions readable and non-duplicated?
• Are title, scale, north arrow, revision and issue status correct?
• Are proposed, existing and demolished works clearly distinguished?

Frequent failures include drawing each view independently, using unverified standard details, dimensioning to finishes when structural setting-out is required, omitting hidden construction at junctions, and allowing CAD layers to plot incorrectly. A visually attractive sheet can still be technically unsafe or unbuildable.

11. Applied case: small community learning centre

Background

The following is an illustrative case. A single-storey community learning centre contains two classrooms, a multipurpose room, accessible toilets and a covered entrance. The design team requires a floor plan, roof plan, RCP, four elevations and two sections at a diploma-level documentation stage.

Problem

An initial drawing set showed a plausible floor plan, but the roof plan had a ridge displaced from the centreline, the north elevation showed windows at unequal heights, and the RCP placed light fittings over a structural beam. The door schedule also listed a 900 mm accessible entrance, while the plan showed a narrower clear opening.

Analysis

The errors resulted from producing the elevations and roof independently from the floor plan. There was no common datum, and the door schedule was prepared before the opening geometry had been checked. The section did not pass through the entrance or the beam, so it failed to reveal the conflicts.

Approach and solution

The team established a structural grid and set the finished floor level as the principal datum. Wall and opening geometry was corrected first. Door and window blocks were tagged and linked to a schedule. A roof ridge was located from the wall grid and checked in both section and elevation. The RCP was overlaid with the structural and mechanical backgrounds before light positions were finalised. A section through the entrance verified threshold, lintel, ceiling and roof relationships.

A review matrix was then prepared with rows for every door, window, room and level and columns for plan, elevation, section, schedule and specification. Each item was marked “consistent,” “not applicable” or “requires correction.”

Outcome

The revised set showed consistent opening locations, a complete accessible entrance, a credible roof drainage arrangement and coordinated ceiling services. The principal improvement was not a new CAD command; it was the use of a shared geometric basis and a deliberate checking process.

Learning points

1. Coordination is a design-management activity as well as a drafting activity.
2. Sections should be selected to expose likely construction conflicts.
3. Schedules are checking tools, not merely presentation tables.
4. A final plot review is essential because line weights, clipping and text may change at issue scale.

12. Professional, regulatory and technological considerations

Architectural documentation has safety, accessibility and legal consequences. Drawings must comply with applicable building regulations, planning conditions, fire requirements, accessibility provisions, energy rules and construction standards. Copyright, licensing and data security also matter: manufacturers’ details and consultants’ drawings must be used under appropriate permissions, and project files should be protected from unauthorised alteration.

Building information modelling (BIM) and AI-assisted drafting can support object classification, clash detection, automatic schedules and drawing generation. Their outputs require human verification. AI may reproduce outdated standards, infer geometry incorrectly or generate plausible but non-compliant details. A professional remains responsible for checking dimensions, sources, permissions, constructability and regulatory compliance. The safest use of automation is to accelerate repetitive work while retaining traceable review and approval.

Chapter Summary

Plans, elevations, sections, roof plans and reflected ceiling plans communicate different aspects of the same building. A floor plan establishes horizontal arrangement and openings; a roof plan explains drainage and roof geometry; an RCP coordinates ceiling construction and services; elevations show external form and finishes; and sections explain vertical construction, levels and spatial relationships. Effective documentation depends on common datums, consistent geometry, controlled line weights, clear dimensions, schedules and disciplined CAD procedures. Stairs, openings, finishes, roofs and levels must be checked across every relevant view. Professional drawings also require compliance with regulations, controlled revisions, responsible use of digital tools and systematic quality assurance.

Key Terms

Architectural plan: A horizontal orthographic representation of a building, usually cut above floor level.

Elevation: A vertical orthographic view of an external or internal face.

Section: A drawing made by cutting vertically through a building to reveal construction and space.

Reflected ceiling plan: A ceiling view represented as reflected onto the plan plane.

Roof plan: A top view showing roof geometry, slopes, drainage and penetrations.

Datum: A reference level or coordinate from which dimensions are established.

FFL: Finished floor level.

AFFL: Above finished floor level.

Grid: A coordinated system of reference lines used for setting out.

Poche: Solid graphic emphasis applied to elements cut in section.

Line weight: The plotted thickness used to distinguish graphic importance.

Opening schedule: A tabulated record of doors, windows or other openings.

Finish schedule: A record of floor, wall, ceiling and associated finishes.

Riser: The vertical component or height of a stair step.

Going: The horizontal depth of a stair tread.

Parapet: A low wall at the edge of a roof, balcony or terrace.

External reference: A linked drawing file used as a coordinated background.

Revision control: The process of recording and managing drawing changes and issue status.

Review Questions

Short Answer Questions

1. What is the principal difference between an elevation and a section?
2. State four types of information normally included on a floor plan.
3. What is the purpose of a reflected ceiling plan?
4. Why should a common vertical datum be used across a drawing set?
5. Name three checks that should be made between a plan and an elevation.

Long Answer Questions

1. Explain the purpose, content and graphic conventions of a coordinated floor plan.
2. Describe a professional workflow for producing plans, elevations and sections in CAD.
3. Explain how roof geometry and drainage should be represented and coordinated.
4. Discuss the role of schedules in architectural documentation and quality control.
5. Explain why sections should be selected strategically rather than placed arbitrarily.

Analytical / Application Questions

1. A window appears in the floor plan and schedule but is missing from the elevation. Describe a systematic method for locating and correcting the coordination failure.
2. A 3,000 mm floor-to-floor height is to be divided into 17 equal risers. Calculate the riser height and identify the additional regulatory and spatial checks required before approval.
3. An RCP places luminaires, diffusers and access panels in a room containing a deep beam. Analyse the coordination problem and propose a sequence for revising the ceiling layout.

Multiple Choice Questions with Answers

Question 1

Which drawing primarily communicates the vertical construction relationship between foundations, floors, walls and roof?

A. Floor plan

B. Section

C. Roof plan

D. Reflected ceiling plan

Correct Answer: B. Section

Question 2

What is the main purpose of a reflected ceiling plan?

A. To show foundations and footings

B. To show ceiling construction and coordinated ceiling services

C. To show only external wall finishes

D. To replace the roof drainage plan

Correct Answer: B. To show ceiling construction and coordinated ceiling services

Question 3

A roof slope is 1:20, using vertical rise to horizontal run. What is the percentage gradient?

A. 2%

B. 5%

C. 20%

D. 50%

Correct Answer: B. 5%

Question 4

Which dimension group normally communicates the total building length and width?

A. Detail dimensions

B. Furniture dimensions

C. Overall dimensions

D. Finish dimensions

Correct Answer: C. Overall dimensions

Question 5

If a floor-to-floor height is 2,800 mm and there are 16 equal risers, what is the riser height?

A. 150 mm

B. 160 mm

C. 175 mm

D. 200 mm

Correct Answer: C. 175 mm

Question 6

Which item is most appropriately checked against both a floor plan and a section?

A. North arrow only

B. Stair rise and landing arrangement

C. Title-block logo

D. Sheet border colour

Correct Answer: B. Stair rise and landing arrangement

Question 7

What does a common vertical datum provide?

A. A decorative hatch pattern

B. A reference from which levels are consistently established

C. An alternative to all dimensions

D. A method for selecting door hardware

Correct Answer: B. A reference from which levels are consistently established

Question 8

Which roof-plan feature indicates the collection and discharge of rainwater?

A. Room name

B. Door swing

C. Gutters and downpipes

D. Furniture block

Correct Answer: C. Gutters and downpipes

Question 9

Why are elements cut by a section plane commonly drawn with heavier line weight?

A. To make them appear farther away

B. To distinguish cut construction from elements beyond the cut

C. To indicate demolition automatically

D. To show that they are temporary

Correct Answer: B. To distinguish cut construction from elements beyond the cut

Question 10

What is the most appropriate professional response to an AI-generated drawing detail?

A. Issue it without checking because it was generated automatically

B. Delete all dimensions from it

C. Verify its geometry, sources, constructability and regulatory compliance

D. Use it only if it contains realistic shading

Correct Answer: C. Verify its geometry, sources, constructability and regulatory compliance