56 Chapter 4
- Where grid lines are used on a drawing (such as on a modular drawing), it is not necessary to di-
mension all the grids. Only one grid is normally dimensioned. - Similar dimensions need not be duplicated on the various views.
- Door dimensions may be indicated in the floor-plan symbols or given in a door schedule.
- Curved or angular leaders are often used to eliminate confusion with other dimension lines.
- Dimensions showing location are given to centerlines of doors and windows on plan views.
- To avoid costly mistakes, it is strongly advised to study all the information available before making
a determination regarding the dimensions in question. Check that there is no conflict or discrep-
ancy with the information shown in other views.
4.2 USING SCALES.
Because building projects are too large to be drawn to actual size on a sheet of paper, everything needs
to be drawn proportionately smaller to fit. The views in a set of blueprints are normally drawn at a reduced
scale by the drafter. Scale notations are given with each drawing. The scale of a drawing is usually noted
in the title block or just below the view when it differs in scale from that given in the title block. When draw-
ing buildings to a specific scale, the drawings retain their relationship to the actual size of the building or
object using a simple ratio. This practice of using an accepted standard ratio between full size and what
is seen on the drawings is referred to as scale. The scale used on construction drawings depends on:
- The actual size of the building or object.
- The amount of detail required to be shown.
- The size of sheet selected for the drawing.
- The amount of dimensioning and notation needed.
- Common practices that regulates certain scales (e.g., normal residential structures are generally
drawn at ¼ inch = 1 foot, 0 inches).
Scales require distinct machine-divided markings coupled with sharp edges to achieve accurate
measurements. The shape of the scales may be triangular, flat, or beveled, and they come in various
sizes: they are generally about 12 inches in length although 6-inch scales are also available (Figure 4.4).
The three commonly used drawing scales for reading construction drawings and for the development of
plans are: the architectural scale, the engineering scale, and the metric scale. Many architects and en-
gineers include a statement on their drawings stating that “dimensions shown on the plans take prece-
dence over scaling.” Some of the problems associated with scaling a drawing include size changes due
to reproduction methods, last-minute forced dimension changes, and varying degrees of drafting accu-
racy depending on the skills of the drafter.
Architect’s Scale.
Architectural scales are normally flat or triangular in shape and come in different lengths, the 12-inch
(30-cm) triangular shape being the most popular. All three sides of the triangle scale (except those
with a 12-inch scale) contain two scales on each usable surface. Each of these scales uses the full