Information Sheet 1.8.
1-4
Draft Sections
What is Section?
The designer shows the internal construction of a building by means of
a section. Section drawings are prepared for interior details needed to guide
construction. Interior elevation drawing shows builders how to construct and
install special features of a home. These features include closets, cabinets,
bathtubs and other special details.
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, as
illustrated on the drawing below.
In this case, the section drawing would be named 'Section B-B'.
Figure 8.1 Section
In this case, the section drawing would be named 'Section B-B'.
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.
The scale of a section drawing 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, a wave indicates insulation and so
on.
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. Increasingly,
section drawings can be generated automatically by 3D modelling software,
including perspective sections where required.
Figure 8.2 Perspective Section 1
Techniques for preparing interior elevation drawings are the same as
for exterior elevations. Use a floor plan to locate key vertical lines after
horizontal dimensions have been indicated.
Section is a type of drawing which shows the interior or inside of a building
or structure.
1
Retrieved from https://www.designingbuildings.co.uk/wiki/Section_drawing
Cross section is a type of section where the cutting-plane line is drawn
horizontally.
Longitudinal section is a type of section where the cutting-plane is drawn
vertically.
Cutting plane line, a heavy line which shows the exact location where the
plan is cut.
What are the different types of sections used in architectural drafting?
1. Structural section shows the entire building construction. This is
useful in planning for structural strength and rigidity, determining the
length of members and specifying sizes.
2. Wall section shows the construction of a typical wall. This section is
useful in determining sizes and material specification for all rough
members.
3. Detail section shows any deviation from a typical section. It is drawn
to a larger scale.
Figure 8.3 Structural section of a residence
Figure 8.4 Typical section of a residence
Figure 8.5 Atrium pool detail for a residence
Full Sections
Architects prepare drawings that show the building cut in to half to
show the internal structure. This is known as longitudinal section, meaning
lengthwise. When it is cut across, it is called transverse section. It is imagined
that a plane is passed through the building cutting it in half by a cutting plane
line.
There are different ways of drawing the cutting plane line, most
especially if it interferes with dimensions as shown in these figures. 2
Arrows on the cutting-plane line determine the
position from which these sections are viewed.
What are the steps in drafting Sections?
2
Gregorio, M. S. et.al. (2009). Drafting Technology: Drafting Architectural Layout and
Details. Marikina City.
1. From the given plan, indicate the path of the imaginary cutting plane
along the floor plan. Indicate the position of the line of sight or viewing
by means of arrow heads.
2. Transfer horizontal dimension from the floor plan to the section using
a metric scale with appropriate scale ratio.
3. Indicate the vertical dimensions from the ground line to the floor line,
the ceiling line and the ridge line using the standard vertical dimension
as provided in the low-cost housing regulations. The standard
dimensions are 2.80 m. from the floor line to ceiling line and 1.20 m. to
1.80 m. ceiling line to the top of the ridge.
4. Draw the outline of the building using the measurements as marked on
the paper.
5. Darken the outline and draw section lines on portions of the building
that come in contact with the cutting plane.
6. Finalize the drawing by labeling it.
7. Repeat the same procedure for the cross section drawing. 3
3 Gregorio, M. S. et.al. (2009). Drafting Technology: Drafting Architectural Layout and
Details. Marikina City.
