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Construction blueprints: The ultimate guide

If you need to participate in a sizeable construction project, you will undoubtedly need construction blueprints. Construction blueprints layout a project’s plan, and learning how to read blueprints is essential. Almost all contractors prepare blueprints in certain stages, and those who do not use blueprints end unsuccessfully. This guide will cover the basics of construction blueprints, their information, and how to decipher that information.

What is a construction blueprint?

A construction blueprint is a 2D detailed representation of the details necessary to complete a project. The blueprint shows building design, the materials to be used, and features such as windows, doors, and appliances.

If you plan on undertaking a construction project, you need to know how to read blueprints. By-passing this step will lead to poor quality of work on site. We usually make construction blueprints in the design stage of the preconstruction phase of a project. The blueprints come in handy if you consider doing modifications and repair work. Following dimension guidelines also ensure work progresses smoothly and helps deal with project delays and cost overruns.

The term blueprint was coined in 1842 before the Civil War by chemist and photographer John Herschel. He developed a form of drawing by overlaying a translucent paper on top of a sheet of paper with the original drawings. Through the contact print process, thin lines of the drawing would appear on the fine paper. The translucent paper was photosensitive, and once exposed to light, the drawing would turn blue except where there were drawing lines as the drawing lines shielded the paper from exposure to light, and they remained white.

By the 1990s, Computer-Aided Design went mainstream, and it was possible to produce digital illustrations on a computer and print them on a plotter. The blueprint process saved the tedious hours wasted in hand tracing drawings. Today, blueprints are not necessarily blue. They are black lines on a grey background.

What is included within blueprints?

Blueprints are often hard to understand as they have pages of content that represent different parts of a project. To make them easier to read, project designers consistently format them. The common elements in almost every blueprint are:

  • Title sheet
  • Site plans
  • Floor plans
  • Detail images
  • Elevations and sections
  • Mechanical, Electrical and Plumbing (MEP) Drawings
  • Structural Drawings

These blueprint elements have scales, symbols, and abbreviations to make them easy to read. The blueprints also incorporate additional details such as building codes, building permits, scheduling, and quality specifications.

The importance of blueprints 

We cannot understate the importance of construction blueprints. They carry a lot of details and specifications of projects. Implementing them well improves the functionality of the project and helps one meet project objectives.

The main idea behind blueprints is that they are a part of construction planning used to give a realistic depiction of the project. They are succinct and well-coordinated to help reduce misunderstandings in a project.

Construction blueprints detail the materials, procedures, and principles needed to finish the project. They also show the required course of action of building parts. They help you countercheck your compliance with the project’s specifications and regulations.

Construction blueprints allow for smooth project regulation by providing the builders with significant information. They are an excellent resource for future use in maintenance and troubleshooting.

importance of blueprints

Types of blueprints in construction

There are different types of blueprints used in the building process of a project. Some are specific to some construction phases of a project, and others are used from start to finish. The main common types of blueprints are architectural, mechanical, and structural blueprints.


The architectural blueprint depicts the overall appearance of a building both inside and outside. It shows the orientation of a project and the layout of the rooms. The drawings included in the architectural blueprint are the site, floor, ceiling, detailed drawings and elevations, and sections.

The site plan is a map that shows the structure’s orientation on the piece of land. This drawing also shows the property lines of the land, distinct landscape features, driveways, power lines, utility lines, fencing, and other on-site structures.

The floor plan shows an aerial view of the house sliced from about four feet off the floor level, and it gives a layout of features such as walls, furniture, windows, and doors. The ceiling plan gives the dimension, materials, and critical information on the placing of the ceiling in the rooms.

Some features in a project are magnified and featured in detailed drawings to show the builder how to construct them. The elevations and section drawing show the vertical building layout and how the building appears if you stand above, in front, behind, or next to it. On the other hand, section drawings show how the building would occur if you cut through the cross-sections of some parts of the structure.


On completion of the architectural drawings, the architect sends these drawings to the structural engineer, who comes up with the structural drawings. Structural drawings are shown from the ground up. They outline the skeleton of the structure and how to frame the house.  They have details on the foundations, slabs, walls, columns, beams, trusses, and roofs. The architectural drawing shows the visual representation of the project, whereas the structural print shows how to erect the structure so that it will not tumble down.

MEP (mechanical, electrical & plumbing)

The MEP part of a building is what brings the building to life. It is responsible for the water supply and piping, electrical and communication systems, and ventilation. The MEP engineer develops the drawings that lay down these specifications. It is essential to know the placement of these systems to leave space for these features.

The Mechanical drawing plans include water systems, HVAC (Heating Ventilation and Air Conditioning) Systems, Digital control systems, and exhaust systems.

The Electrical plans show the requirements for power generation and distribution on-site. It also indicates lighting and fire protection systems, wiring systems, and standby power systems.

The plumbing drawings show the complex sewage and piping routes. The plumbing drawings are natural gas piping, acid waste piping, hot and cold water pipelines, and ventilation lines.

Types of blueprint sheets

  • G sheets represent general sheets – These sheets have the cover sheet, plan index, and plot plans.
  • Sheets are architectural plans -The Architectural drawings show ceiling plans, building sections, roof plans, floor plans, and more wall sections.
  • M sheets refer to mechanical plans – Mechanical drawings have information about HVAC systems, control wiring, duct work, and refrigerant piping.
  • S sheets refer to structural engineering plans – Structural drawings depict framing plans, foundation plans, and roof structure plans.
  • L sheets are landscape plans- They detail the areas outside the building showing where shrubs, plants, and trees will be planted.
  • E sheets are electrical plans – They show the location of all electrical fixtures, panel boxes, and circuits. Electrical schematics show the function of the actual electrical circuit. Wiring diagrams indicate the physical layout of the wires.
  • P sheets represent plumbing plans – These plumbing plans show the type and location of plumbing in a structure.
  • Window schedule, door schedule, and finish schedule – Schedules describe the size, material, and style of the doors, and windows, with other finish types.
  • Specifications sheets- They have detailed descriptions of all the materials.


How to read blueprints 

All construction workers need to read blueprints and draw the correct conclusions. The first step when reading blueprints is scanning the plan and reading all notes and specifications included. After familiarizing with this, one can then proceed to study the details.

The next step is to focus on the plan views. These can be floor plans, roof plan drawings, structural drawings, or MEP drawings. A professional contractor needs to read the specific items that encompass the scope of work. After reading this, they will put together the pieces and follow through the building process.


Each drawing comes with a different scale, and it is essential to follow the correct scale to avoid interruptions and mistakes in the project. The most common scales in building plans are 1:100, 1:125, and 1:200. For structural members, the most common scales are 1:12.5, 1:25, 1:50, and 1:75.

When we mark changes in drawings off-scale, it is crucial to countercheck during construction to avoid reworks. The contractor should also check whether the elevations of the building are correct. If there is any missing information, they should correct it and add it to the drawings.


Sections of different building components are essential to helping the contractor see how various building components should be constructed and how they connect. Sectional drawings also show ceiling heights, floor elevations, and fire separations. With these drawings,  one can understand how the building components accommodate each other and the occupants. One also needs to cross-reference the section drawings to the plan views to understand the origin of each section drawing.

How to read blueprint symbols

How to read blueprint symbols

We use hundreds of symbols in construction drawings, but not all are universal. There are symbols for materials, building components, and utilities in a project. Each project comes with a list of characters and abbreviations to avoid confusion. The unique abbreviations and symbols ensure that everyone is on the same page. Blueprints are sometimes challenging to read, but having a centralized system helps the involved parties spot errors before they occur.

Different blueprint perspectives

Plan view

This highlights each floor of the building showing the blueprint as a two-dimensional view from above.

Elevation view 

These show how a building will look from different sides like the front, left, right, and rear. You see the elevation view as if looking at it directly as it is drawn on a vertical plane.

Cross section

It shows a building as if it were vertically sliced in half. They show girders, beams, and columns with joists and how they fit together. The relationship between floor heights and stairway designs, amidst other elements, is shown in the cross section.

Isometric drawing

Isometric means equal measure, and isometric drawing refers to a 3D representation that has 30 degree angles. Plumbing connections and room design can be seen in this drawing as the view seems as if one viewing from one corner of the building. 


Below are the answers to the frequently asked questions concerning construction blueprints.

Are construction drawings the same as blueprints?

Yes, construction blueprints are the same as construction drawings as they depict a project’s layout on paper.

Who creates construction blueprints?

The construction blueprints are made by architects, designers, and engineers, depending on the construction specifics required.

Do blueprints have to be blue?

Blueprints today do not have to be blue. Blueprints today are represented using gray-black or gray lines on white paper.


Construction blueprints are a fundamental part of any project regardless of the project size. Without updated construction blueprints, project teams can’t perform their tasks on time and avoid wasting resources. Any person starting in the field should learn how to read and interpret construction drawings. The use of construction software makes making blueprints more efficient and easy.