The Importance of Print Reading Skills
Let's start with the basics. Understanding how to read prints in construction is like a carpenter knowing how to use a hammer, drill or tape measure or a doctor knowing how to use a scalpel, etc. It should be a basic knowledge requirement for any person in the construction and contracting environment.
Drawings (construction documents, prints, blue prints) provide the Owner, General Contractor, Sub-contractors, and Suppliers the information needed to bid and build the project.
Visualizationof the plans is the initial component. Viewing an Architect provided perspective of the project, a detailed elevation or simply flipping through the drawings begins the Print Reading process. Absorbing the image, the entirety of the project provides a sense of completeness. Interpretation of the information follows visualization. Interpretation requires more time delving into the drawings. Each building is different and every architect and engineer draws and details each project differently. Interpretation begins by flipping through the entire set, sheet by sheet, and noting the information pertinent to your scope of work. I will explain more on this later.
I have been asked, “How did I learn to read drawings so well?” I earned my degree in Architecture, spent several years drawing buildings for a variety of architects and engineers, estimated for a General Contractor, and did some project management. My work experience required reviewing plans repeatedly and researching the information needed for each project. The more I did this, the more I understood print reading.
So how do you get started if you have never or seldom looked at drawings? Let’s begin with the typical organization of plans. Plans are broken into types based on the kind of work that is being conveyed.
Cover sheet / Title Page usually includes the index of drawings, a pictorial image, site location, names of companies involved, lists of symbols and materials legend.
- “C” = Civil drawings; anything related exterior of the building
- “A” = Architectural drawings; plans, elevations, sections, finish schedules and details
- “S” = Structural drawings; foundations, reinforcing steel, structural steel, plans sections and details
- “M” = Mechanical
- “P” = Plumbing
- “M” = HVAC
- “E” = Electrical
Example: A.10.1-architectural drawing, sheet 10.1; P3.7-plumbing drawing, sheet 3.7. This is why understanding the Cover / Title sheet is so important.
*Note not all architect / engineers use the letter number system.
Before computers, draftsmen drew the building drawings by hand, t-square and triangle. Since the advent of computers, the means of creating drawings changed. The initial drawings were called CAD (computer aided drawings) which are full size building drawings done by the architect. Currently architects use BIM (Building Information Model) which includes every piece of information about the building input into the building in 3 dimensions. BIM is capable of coordinating all of the architectural, structural, mechanical, plumbing, and electrical plans.
When you pick up a set of drawings begin follow the steps below;
- Review Cover / Title sheet
- Flip through the drawings page by page
- Tag pages with information related to your scope of work see Fig. ??
- Highlight / color in areas pertaining to your scope of work see Fig ??
- Read the specifications and understand what pertains to you. I have been quoted saying “READ THEN OR WEEP”
Although drawings are created in full scale on the computer, they obviously can’t be printed on sheets of paper in full scale. So they are reduced to an appropriate scale which includes the information that is being conveyed to fit on the size of the sheet chosen. There are two basic scales used in the construction industry: an “Architect’s” scale and an “Engineer’s” scale. The architect’s scale is typically used for the interior of the building, displaying plans, sections and details while the engineer’s scale is typically used for the exterior of building. An architect’s scale uses fractions of an inch related to a foot; ie: 1/4 = 1’–0” or 3/4“= 1’-0” which means that each actual 1/4” or 3/4” in scale equals an 1’-0” in full scale. An engineer’s scale relates an inch to a number of feet; ie: 1” = 20’ or 1” = 50’ which means that each inch in scale equals 20’ or 50’ in full scale. There is not enough time in this article to provide a full understanding of the use of scales but to retrieve dimensional information from a set of drawings it is important to understand the scale of a drawing and the use of these instruments.
If you are in the contracting building industry and can’t read construction drawings you are at a sever disadvantage with your competition. Learning to read Construction Drawings prints is a life long process and once you begins it will never stop. I still today learn every time I open a set of drawings. So the first steps is learning how to open the drawings and become familiar with the terms, symbols, language and how to find your away around the prints.
To learn more about Print Reading classes, please visit my website www.printreading.us
Daniel P. Dorfmueller