What you'll learn
A building drawing has to show a three-dimensional building on flat paper in a way a builder can use — and that is done using plans, elevations and sections. For CSEC Technical Drawing you need to understand what each of these views shows, the conventions and symbols used in building drawings, and how the views relate to one another. This guide covers the purpose of each view, the standard symbols and conventions, scales, and how the views work together to describe a building fully. By the end you should be able to explain the difference between a plan, an elevation and a section, and interpret a building drawing.
Key terms and definitions
Plan — A view looking straight down on a building, showing the layout of rooms.
Elevation — A view of one side (face) of a building, seen straight on from outside.
Section — A view showing what a building looks like when cut through, revealing internal details.
Floor plan — A plan showing the arrangement of rooms on one floor.
Scale — The ratio between a size on the drawing and the real size.
Convention — An agreed standard way of representing something on a drawing.
Symbol — A simplified drawing representing a feature such as a door or window.
Site plan — A drawing showing the building in relation to its plot of land.
Core concepts
Why several views are needed
A building is three-dimensional, but paper is flat, so no single view can show everything. Building drawings therefore use several related views — a plan, one or more elevations, and one or more sections — which together describe the whole building. Each view shows different information, and a builder uses them together to understand the layout, appearance and construction.
The plan
A plan is a view looking straight down from above, as if the roof had been removed. A floor plan shows the layout of the rooms on a floor: the position of walls, doors, windows, and the sizes of rooms. It is the most important view for showing how the building is arranged and how big each space is. A separate plan is usually drawn for each floor of the building. A site plan is a different kind of plan, showing the whole plot of land and where the building sits on it, including boundaries and access.
The elevation
An elevation is a view of one side (face) of the building, seen straight on from outside, as if you were standing in front of it. Elevations show the external appearance — the position and shape of doors, windows, the roof, and the overall proportions. A building usually has four elevations (front, back and two sides), often named by the direction they face (for example, north elevation). Elevations do not show room layout; they show how the outside looks.
The section
A section shows what the building looks like when it is imagined cut through along a chosen line, revealing the internal construction. A section can show details that plans and elevations cannot, such as the thickness of walls, the height of floors, how the floors and roof are constructed, and the foundations. The position where the section is taken is marked on the plan with a section line, so you know exactly where the cut has been made.
Scale in building drawings
Buildings are far too large to draw full size, so building drawings are drawn to a scale. Common scales include 1:50 or 1:100 for floor plans and elevations, meaning the real building is 50 or 100 times larger than the drawing. A site plan uses a smaller scale such as 1:500 because it covers a larger area. The scale must be stated on the drawing, and all measurements are taken using it.
Conventions and symbols
Building drawings use standard symbols and conventions so that anyone can read them the same way. For example, there are recognised symbols for doors (often shown with an arc for the swing), windows, sinks, and other fittings, and standard ways to show walls, hatching for materials, and dimensions. Using these conventions means a drawing produced by one person can be understood by builders, clients and officials without confusion.
How the views work together
The three types of view are related and complement each other. The plan shows the layout from above, the elevations show the outside appearance from each side, and the sections show the internal construction where cut. A point on the plan corresponds to points on the elevations and sections, so features line up across the views. Reading them together gives a complete picture of the building.
Types of building drawing at different stages
Different building drawings are used at different stages of a project. Sketch or preliminary drawings are rough drawings used early on to explore ideas with the client. Working drawings are the accurate, detailed, scaled drawings — the plans, elevations and sections — that the builder actually uses to construct the building. Detail drawings show a small part of the building, such as a window or a junction, at a large scale to make the construction clear. Knowing which drawing is used when helps you understand how a design moves from an idea to a finished building.
Lines used in building drawings
As in all technical drawing, building drawings use different line types to show different things, and using them correctly is important. Thick continuous lines show the main outlines that are cut or seen; thin continuous lines are used for dimensions and general detail; and dashed (hidden detail) lines show features that are behind or below the plane of the drawing, such as an object hidden by a wall or a foundation below floor level. Centre lines (a long-short-long chain line) mark the centre of symmetrical features. Using the correct line type makes the drawing clear and unambiguous, and marks are given for applying these conventions properly.
Worked examples
Example 1: Identifying the view
Which view would you use to show the layout of the rooms on the ground floor? A floor plan, because it is a view looking straight down that shows the arrangement of walls, doors, windows and room sizes on that floor.
Example 2: Choosing a view for wall thickness
A builder needs to know the thickness of the walls and how the floor is constructed. Which view shows this best? A section, because it shows the building as if cut through, revealing internal details such as wall thickness, floor construction and heights that a plan or elevation cannot show.
Example 3: Explaining an elevation
What does a front elevation show, and what does it not show? A front elevation shows the external appearance of the front of the building — the position and shape of doors, windows and the roof, and the proportions. It does not show the internal room layout, which is shown on the plan.
Example 4: Understanding scale
A floor plan is drawn at a scale of 1:100. A wall on the drawing is 4 cm long. How long is the real wall? At 1:100, the real length is 100 times the drawing length: 4 cm × 100 = 400 cm = 4 m.
Common mistakes and how to avoid them
A common error is confusing a plan and an elevation. A plan is a view from above (room layout); an elevation is a view of a side from outside (external appearance). Keep the direction of view clear.
Students often think a section is the same as an elevation. A section shows the building cut through to reveal internal details, while an elevation shows the outside face without cutting. The section line on the plan tells you where the cut is.
Another mistake is forgetting to state or use the scale. All building drawings are to scale, and measurements must be worked out using it — for example, at 1:100, 1 cm on the drawing is 1 m in reality.
When drawing, do not invent your own symbols. Use the standard conventions for doors, windows and materials so that others can read the drawing correctly.
Finally, remember that the views are related — a feature on the plan lines up with the same feature on the elevations and sections, so they must be consistent with each other.
Exam technique for "Building Drawing: Plans, Elevations and Sections"
Be clear about what each view shows: plan (layout from above), elevation (external face from the side), section (internal detail where cut). Questions often ask which view best shows a particular feature, so match the view to the information needed.
For scale questions, use the scale to convert between drawing and real sizes, showing your working. Know common scales (1:50, 1:100 for plans and elevations, 1:500 for site plans).
Be ready to recognise and use standard symbols and conventions, and to explain how the section line on a plan shows where a section is taken. Use precise terms — plan, elevation, section, scale, convention — throughout, as accurate technical vocabulary earns marks.
Quick revision summary
- A building is described using related views: plans, elevations and sections, which together show the whole building.
- A plan is a view from above showing room layout; a site plan shows the building on its plot.
- An elevation shows one external face of the building (doors, windows, roof) but not the internal layout.
- A section shows the building cut through, revealing internal details like wall thickness and floor construction; the section line on the plan shows where it is cut.
- Drawings are to scale (e.g. 1:100 for plans, 1:500 for site plans), which must be stated and used for measurements.
- Standard symbols and conventions (for doors, windows, materials) let everyone read the drawing the same way.