What is a section?

A section is a view of a building obtained when the drawing is cut through another plane along any axes or direction. The plane which cuts the drawing is known as the cutting plane. Creating sections of a plan of the building is important as the section gives all the details about different parts of buildings that are not visible in the plan. The section of a building is drawn using alternate small and long dashes, known as section lines.

Drawing sections

A drawing section is an important part of drawing a plan. Sections represent both the interior and exterior parts of a building, including the critical parts of a building. The procedure for drawing the sections are as follows-

• To draw sections, first, the plans of a building need to be prepared.
• Next, the critical parts of the plan need to be identified. Walls and stairs are mandatory to be included while drawing any section.
• Mandatory one section in the horizontal direction and one in the vertical direction need to be drawn.
• Next, sections should be drawn using section lines. In the case of more than one section line, each section line should be denoted using different notations, primarily using capital alphabets and numbers.
• The section lines should consist of an arrow at the end of the line, which represents the direction in which the section should be viewed.
• The line should be straight for the convenience of viewing, but it is not mandatory to keep it straight. The line can take an indirect route if important features are missing.
• Different hatchings, such as lines, boxes, diagonal lines, brickwork, and so on should be provided in the plan to represent different components of a building.

Section of a wall

While sectioning a plan, walls are important to be sectioned as wall consists of various materials, various sizes, and properties. Hence, to execute a wall perfectly on the site, it is necessary to obtain details about the internal structure of a wall. The walls are classified as brick walls, masonry walls, wooden walls, stone walls, and so on in terms of material used, bearing walls and non-bearing walls in terms of structural load carrying characteristics, and curtain wall, partition wall, party wall, infill wall, shear wall, cavity wall, and so on, as per the serving characteristics. Following are the components that need to be displayed while drawing a section of a wall -

• Foundations– In the case of load-bearing walls, foundations are mandatory to design as in a load-bearing structure, the load of the whole structure is transferred to the soil through foundations, and to the foundation through walls. The foundations should be drawn to proper shape and size, and the material of the foundation should be hatched using standard hatches, such as a combination of dots and triangles for the concrete hatch, diagonal lines for brickwork, alternate diagonal straight and dotted lines for rubble masonry, and so on.
• Walls– The walls should be drawn to proper shape and size, the drawings of the walls must be straight in case of straight walls or properly angled in case of curved walls as per the design, to avoid errors on the site. The wall should be displayed using proper hatches, depending upon the type of material used. For example, dotted hatches for masonry walls, rectangular bricks or diagonal line hatches for brickwork, and so on. The section line should cut at least one window or ventilator provided in the wall.
• Windows and ventilators– The windows and ventilators should be drawn at the proper height in the sectional view. The sill level and lintel level should be considered properly as per the standards while designing and drawing windows and ventilators.
• In the case of cavity walls, the section should include the inner wall, outer wall, and the insulation material provided along with proper and different hatchings for all.

Section of a staircase

Drafting the section of a staircase is one of the most difficult parts of any drawing. The section of a staircase should be drafted properly to avoid any mistakes on the site. The section of a staircase should represent the rise, trends, height, mid-landing, and railings of a staircase. Proper hatchings should be given to represent the materials used for the staircase. The section should also represent the reinforcement details in the case of the RCC staircase.

Materials used for drawing sections

The sectional drawing can be created manually or by using certain software. The various materials necessary for preparing a sectional drawing are given below-

• Drawing paper– The sections are created on a blank white drawing paper of standard size using pencils of various shades. As per the standards, drawing sheets from the size A to E should be used for this purpose.
• Pencils– The drawings of all sections are prepared using different shades of a pencil. Generally, H, 2H, 3H, and HB shades are used. For the main components, the dark shade of the pencil is used and for the hatching purpose and to show the hidden components, the light shade of the pencil is used.
• Tracing paper– The tracing paper is used to copy the original technical and architectural drawings of sections and other components from the drawing paper so that the original drawing can be pasted on another drawing paper accurately using the diazo copying process.
• Mountboard– The mount board is used to display, render, present, or frame the sectional drawings.
• Some other materials used for drawing the sections include a compass to draw circular components, roller scale, and Set Square to draw straight, parallel, and perpendicular lines, protractor to measure angles, french curve to draw curves, and so on.

With the development in technology, various software like AutoCAD is developed as an alternative of traditional drawing papers to draft sectional drawings. The use of software makes it easy to make frequent corrections, saves time, and makes the method of drawing easier.

Context and Applications

The drawing section with alternative materials is useful for the students undergoing the following courses-

• Bachelors of Technology (Civil Engineering)
• Bachelors of Architecture

Practice Problems

1. Which of the following views of a building is obtained when the drawing is cut through another plane along any axes or direction?

1. Elevation
2. Section
3. Compound
4. Lintel

Answer- b

Explanation– Section is a view of a building obtained when the drawing is cut through another plane along any axes or direction.

2. How are the sections of a building drawn?

1. Alternate small and long dashes
2. Straight lines
3. Long dashes
4. Small dashes

Answer- a

Explanation- The sections of a building are drawn using alternate small and long dashes.

3. Which of the following is not a type of wall categorized based on serving characteristics?

1. Curtain wall
2. Partition wall
3. Masonry wall
4. Infill wall

Answer- c

Explanation- Masonry wall is not a type of wall categorized based on serving characteristics.

4. Which of the following is the main material used to copy the original technical and architectural drawings?

1. Tracing paper
2. Drawing paper
3. Mountboard
4. Set square

Answer- a

Explanation- Tracing paper is the main material used to copy the original technical and architectural drawings.

5. Which of the following is used to draw straight, parallel, and perpendicular lines?

1. Tracing paper
2. Roller scale
3. Compass
4. Protractor

Answer- b

Explanation- The roller scale is used to draw straight, parallel, and perpendicular lines.