Architectural drawings that are drawn to scale are used to construct or remodel buildings.
Plan drawings are scale views looking straight down. Examples include floor plans, roof plans, site plans, etc.
Consider the following two-story house:
Here are the floor plans for that two-story house:
Features of these floor plans including:
Note also that the roof overhangs and ridgeline are marked with dashed lines on the upstairs floor plan.
Consider another house, this one build in 1907:
Here is a floor plan of that house, drawn in the 1970s to assist in remodelling:
For this drawing, North is down,
as specified in the plan.
And the scale is
A scale of 1:200 means that 1 mm on the drawing equals 200 mm at the building, 1 cm on the drawing equals 200 cm at the building, etc.
These kinds of drawings are kept at the job site, along with scale rulers to determine measurements from the drawings.
A scale ruler (also called architects scale) is a multi-sided ruler that can be flipped around until the desired scale is in position to take measurments on a scale drawing.
An elevation drawing shows a vertical wall or building side, viewed from a horizontal direction. This type of drawing can be in line with other drawings.
High resolution JP2 files can be viewed in Image Glass
A section drawing is a cut-away view of a wall, or of a building elevation, or of other vertical objects.
In the section drawing of this figure, the roof on the right of the section drawing, is the lower of the two roofs in the elevation drawing. And the roof at the top of the section drawing, is the upper roof in the elevation.
A detail drawing is a drawing of a specific part, such as a light fixture, trim detail, etc. Detail drawings could be section drawings or portions thereof; the terms section and detail may be used interchangably.
We consider section and detail drawings in the
plans that were used to construct
A section drawing of a wall is generally perpendicular to an elevation drawing of the wall: instead of showing the face of the wall, it shows a cross-section view of what the wall is made of, and its dimensions in that direction. Exemplary cut lines on plan or elevation drawings show the position of the section drawing, usually labelled with letters, like AA, BB, etc.
Consider the following plan drawing
that was used to construct the
Note: High resolution JP2 files can be viewed in Image Glass. Use the Plus and Minus keys to zoom in and out.
Zoom in to the lower right portion of the drawing, as shown here:
That section drawing, in the lower right portion of Sheet 1, has its title (Section AA) below the section drawing, along with the scale of the section drawing, since the scale is different than the scale of the plan drawing.
In the plan drawing,
to the left of the lower part of that section drawing,
zoom in and notice,
The foundation footing
projecting inward beyond the cut
(above cut AA in the floor plan),
illustrated with dashed lined rectangle
on the floor plan
The projecting footings are positioned along the downhill side of the building, at chord lengths of 22 feet-10 inches (274 inches):
Returning to Section AA, zoom in to the main floor level (datum zero) on Section AA to see the floor vent detail.
From the position of Section AA cut on the plan, we have already followed the exterior wall (round building perimeter) to the lower part of the drawing that shows the chord lengths. Now keep going along the curved wall, further to the left in the plan.
Where the last chord line ends, a note outside the building perimeter says the dashed line that follows outside the building perimeter is the Line of footing, see Section AA.
Referring back to Section AA (zoom in to the lower-right portion of the drawing shown in Figure 13), we see that footing (which wraps around the outside of the building and extends to the right in the section) was specified in the drawing to be 14 inches high, with the bottom of the footing at least 24 inches below ground level.
Continuing on, the wall is interrupted (horizontal contact offset) at the outside of the flower box (left side of Figure 16 above), to reduce thermal expansion ballooning of the building.
Moving further along the round wall, past the inner side of the flower box, is the last projecting footing of the round portion of the building (which again references Section AA), after which begins the polygonal (non-round) portion of the building.
Follow along the straight exterior walls of the building, around an obtuse corner, and find the cut lines for Section BB.
Section BB is drawn above Section AA (on the right side of the sheet) without specifying scale because it uses the same scale as Section AA below it.
Sheet 2 shows the two entrances where the reading room meets the polygonal portion of the building (along a secant), at datum zero of the plan, which is the main floor level that extends throughout the polygonal portion of the building and along the inside perimeter of the round reading room.
The reading room has multiple coencentric floor levels, beginning with the outer floor at main floor level of the building (datum zero), with each floor level inward 9 inches lower (negative datum).
There is a step inset
between desks or shelves
that arc along edges
of floor levels,
to form two
Architectural scale drawings that are used to construct a building are called working drawings.
Working drawings list lengths (dimensions) as meters (m) and millimeters (mm), not centimeters (cm).
If a dimension has a radix point, the dimension is meters.
The radix point could be a period or a comma,
and is referred to as a decimal point because
SI units only use
If a dimension does not have a radix point (if it is an integer), then it is millimeters.
For example, one-and-a-half meters can be specified as follows:
All three of those are valid and specify the same distance. Using that convention, the suffixes m or mm are not used, and reading the distances becomes easier and less error-prone.
Publicity drawings may use centimeters, because the public uses centimeters. For example, when a consumer shops for furniture, the sizes of furniture are given in centimeters.
To convert millimeters to centimeters, simply remove the least significant digit from millimeters (conveniently possible because SI units use a decimal radix).
This figure shows a floor plan of Apartment B15.
The apartment has
The lower portion of floor plan shows a
Not having cantilever balconies as building add-ons reduces thermal bridging and structural weathering. It is better to hold up small balconies with vertical posts from the ground instead of horizontal cantilever from the building, to reduce structural building membrane penetration. That was done for the second floor of this building. Even better is to use roof terraces, as specified for the top (third) floor in these plans.
Imperial units are used by some legacy systems in Burma and the United States. It is based on feet and inches, with one foot equal to 12 inches.
1 meter (m) = 39.37 inches
1 inch = 2.54 cm