A Master Class In Construction Plans - Smartsheet

Construction plans differ from maps, which cover much larger areas and have much larger scale ratios. Rather, a typical construction plan depicts only one structure and its parts or sections. By changing perspectives and details, it can do so in a number of ways.

Construction drawings also fill an important role in the overall construction planning process. Building departments and local governments must review plans before they will issue construction or renovation permits. Planners estimate building material and labor costs based on plans. In the pre-construction planning and scheduling phase, contractors use plans to create work breakdowns and schedule construction tasks. Once construction gets underway, drawings guide the work.

As physicist John Swain writes for the Boston Globe, blueprints originated after an 1861 discovery by French chemist Alphonse Louis Poitevin. He found that the chemical ferro-gallate, derived from gum, could permanently turn a vivid shade of blue when exposed to strong light. To create a blueprint, one would first place the translucent paper of an architectural drawing over paper coated with unexposed ferro-gallate. Then, they would expose the paper layering to strong natural light. As light passed through the translucent top sheet, turning the ferro-gallate sheet beneath it blue (except for where the drawn lines on the top sheet prevented light from passing through to the bottom sheet), the chemical combination would reproduce a complex, finely detailed drawing in minutes.

This process was called contact printing, and the result was a blueprint: a white-lined, blue sheet of paper that formed a drawing. Blueprints cost a fraction of the money and time that other contemporary reproduction techniques did, so they quickly gained popularity among not only architects, but also scientists and artists who wanted to quickly reproduce complex diagrams.

True blueprints fell out of use in the 1950s. The name stuck, however, and today we continue to call complex design drawings blueprints. Of course, since the mid 20th century, architectural drawings have undergone several evolutions. With CAD (computer-aided design) software, we can now easily visualize them in 3D with varying levels of detail and from a variety of perspectives.

CAD software simplifies the architect’s work considerably. Blueprints’ background color made them very difficult to write on, and it’s much easier to make design changes digitally rather than on paper.

Though modern construction plans vary greatly in scale and complexity, representing everything from small residential to large commercial projects, all construction plans comprise the same essential elements. All buildings, no matter how complex, consist of structural components, mechanical systems, and finishes.

A construction plan will provide the same kind of information regardless of the size or complexity of a project. For example, a floor plan will provide a bird’s eye view of room dimensions and installations regardless of whether it’s drawn for an apartment or a convenience store, and a mechanical plan might detail mechanical systems for either a kitchen or a laboratory. If you can read one, you can read the other; only the level of complexity will vary.

Construction plans are different from a construction company’s business plans, which tell little about specific construction projects and more about how a company wants to develop its business. Construction plans also differ from specifications: A construction plan tells you what you will build, while specifications tell you how you build it.

Specifications will include information on materials you use, installation techniques, and quality standards. While most designers and architects will follow these methods for presenting information, others will annotate specs on construction plans, so the difference isn’t always clear cut. If the information in the specifications conflicts with that of the plans, the usual practice is to follow the specs over the plan.

General contractors, subcontractors, and tradesmen must have a deep knowledge of plan reading, and owners of large commercial projects will want to understand at least the broad strokes of a plan. Small project owners have an advantage if they are familiar with construction plans because they can understand exactly what the builders are going to be build. If you’re a homeowner and you don’t understand the architect or designer depicts the project, ask them so you’re on the same page before construction gets underway.

In fact, the professionals at HomeBuildingSmart recommend that you familiarize yourself with house plans before beginning a construction project, so you know what your tastes are and can provide useful input as the architect creates your construction plan. Remember, you can modify plans, but you can’t undo construction. So, iron out the details while they’re still only on paper.

Blueprints can seem arcane when you’re starting out, but with practice, reading them will get easier. So, if you’re a project owner, don’t shy away from construction plans: Make sure you understand what’s going on with your project.