A 'section drawing', 'section' or 'sectional drawing' shows a view of a structure as though it had been sliced in half or cut along another imaginary plane.
For buildings, this can be useful as it gives a view through the spaces and surrounding structures (typically across a vertical plane) that can reveal the relationships between the different parts of the buildings that might not be apparent on plan drawings. Plan drawings are in fact a type of section, but they cut through the building on a horizontal rather than vertical plane.
The direction of the plane through which the section is cut is often represented on plan drawings and elevations by a line of long and short dashes, called a section plane. If there are a number of sections, the line may have letters at each end indicating the name of the section drawing and an arrow showing the direction that the view takes.
The section line can take an indirect route through a building if this helps show the most important features or junctions in the building
Shading, cross hatching or other fill styles and / or thicker lines can be used to indicate parts of the structure that have been cut through, such as walls, roofs and floors.
It will depend on the size of the building being drawn and the level of detail that needs to be shown. Sections may show the entire building, or may focus on a particular component, junction or assembly. In this case they can be similar to assembly drawings but differ in that they don’t usually include details of the actually assembly process.
Different types of cross hatching can be used to differentiate between different types of component on detailed sectional drawings. Standards exist for hatching that should be used on some common materials, for example, double diagonal lines indicate brickwork
Perspective sections include 3D projection of the spaces beyond the section plane and can be used to give a graphical illustration of the relationship between spaces and building components as well as their depths that can be very helpful in trying to interpret a complex design.
drawing that cuts the building with a vertical plane but only indicates the supporting structural elements. Architectural elements (floor coverings, facade claddings, doors & windows etc.) are not included. However, the position of the openings must be understandable withing the section. Thermal insulation layers and partition walls can be indicated with a dashed line if necassary. Cut-through elements (beams, slabs, loadbearing walls) are shown with thicker line and specific hatching patterns, depending on the scale of the drawing. The beams & columns in view must be represented with a thinner line.
The number of cross sections needed completely depends on the complexity of the design, your planning department requirements and who is building the house.
For Ex: If you are planning to frame your exterior walls in a unique way in order to accommodate a different type of insulation or exterior finishing, it will be important to provide detailed cross sections for these elements.
The cross sections are created once your floor plans and elevations are finished. You need to have completed the structural design for the house, that is, determined the required size and location of all structural walls, posts and beams.
Indicates the plane of the section, which is drawn in a seperate sheet. Includes a reference number or letter (e.g. Section A-A). The Section line must be drawn in a thick line and clearly visible.
An architectural sections drawing that cuts the building with a vertical plane at a specific position. All the elements that are cut through (Wall, slabs, ceiling, footing beams, etc.) are shown with thicker line and specific hatching patterns, depending on the scale of the drawing. The elements in view (doors, windows, handrails etc.) are represented with a thinner line.
_or_only_through_a_wall_(wall_section).jpg "A section might be cut all the way through a building (called a building section) or only through a wall (wall section)")
Mr.A Edirisinghe
Deputy Principal
Vidyartha College, Kandy