112 Chapter 6
In construction drawings as much information as possible is presented graphically, or by means of
pictures. Most construction drawings consist of orthographic views. General drawings consist of plans
and elevations drawn at a relatively small scale. Detail drawings (discussed later in this chapter) consist
of sections and details drawn at a relatively large scale. A plan view is a view of an object or area as it
would appear if projected onto a horizontal plane passed through or held above the object area. The
most common construction plans are plot plans (also called site plans), foundation plans, floor plans,
and framing plans. A plot plan shows the contours, boundaries, roads, utilities, trees, structures, and
other significant physical features on their sites. The locations of the proposed structures are indicated
by appropriate outlines or floor plans. As an example, a plot may locate the corners of a proposed struc-
ture at a given distance from a reference or base line. Since the reference or base line can be located
at the site, the plot plan provides essential data for those who will lay out the building lines. The plot can
also have contour lines that show the elevations of existing and proposed earth surfaces and provide
essential data for the graders and excavators.
The main functions of construction drawings include:
- Instruments for material take-offs: Labor, material, and equipment estimates are made from
working drawings prior to construction. - Instructions for construction: Working drawings show specific sizes, location, and relationships
among all materials. - Means for granting a building permit: Before construction can begin, the local building authority
must review the working drawings to see that they meet the requirements of public safety in
terms of structural soundness, fire, and other hazards. A building permit is issued to the builder
only after approval of the drawings. - Instruments for competitive bidding: In a free-enterprise system, working drawings allow poten-
tial contractors a uniform guide for preparing bids, thereby providing the owner with the most
economical costs. - Means of coordinating among the various trades: Working drawings are the basis of agreement
between material suppliers and specialized trades. - A permanent record for future remodeling or expansion or for legal use in the advent of a dis-
pute: Working drawings eliminate remeasurements in case of future reconstruction. Drawings
must be furnished in case of legal disputes. Building failures might possibly occur by natural, un-
avoidable causes, design errors, or neglect, but the drawings and design calculations are used
as evidence and should be available for the life of the building. - Basis for agreement between owner and tenant: In leasing all or portions of a building, the owner
must use the working drawings in the contract agreement. - A complement to the specifications: In obtaining written information from the specifications, con-
tractors need the working drawings for interpretation. Information from one source is incomplete
without the other.
Shop Drawings.
These are technical drawings prepared by various suppliers participating in the construction. On many
jobs the architect or designer must rely on specialists to furnish precise information about the compo-
nents. For example, if complex cabinetwork is required, it must be built to exact sizes and specifications.