How To Read Floor Plan Measurements

Floor plan measurements are vital to any construction project, and even small mistakes can lead to delays for every subcontractor. Learn how to read construction plans to ensure your floor plan measurements are accurate, avoiding costly errors.

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Construction projects require cooperation between professionals in a variety of trades to complete. Whether working on new construction or remodeling an existing structure, knowing how to read construction plans is vital to producing quality results.

Understanding the floor plan blueprint is useful to contractors across many industries and generates a wealth of information to accurately plan the project budget and timeline. Learn more about how to read plans and specs on your next project and where you can find additional information when you need help.

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How To Read Construction Plans

Construction plans, or blueprints, are 2D architectural illustrations that provide the details needed to complete the featured structure. These plans can be provided as a printout, on either oversized sheets or standard notebook paper, or as a digital file. When receiving your construction plans, it's important to look them over as a whole to get an idea of what the finished structure is meant to be. If you can get an image in your mind, many of the details will make more sense as parts of the whole. Once you have a strong idea of the architect's vision, it's time to look at the details as they pertain to you. There are several elements you should be able to identify.

Scale & Direction

Scale is an important consideration when looking over your construction plans. Multiple plans are often drawn for the same structure to focus on different areas of the project. Sometimes each of these plans will be drawn to a different scale, so you must take the time to verify the scale being used for the plans relevant to your portion of the project.

If you're a general contractor, you'll need to know each of the scales and how they all fit together to help direct your subcontractors. While reviewing the scales used for the blueprints, also make note of the directions given. Plans will usually have a north, south, east, and west designation to confirm how the structure is to be oriented on the site, and this information is critical.

Symbols & Abbreviations

One of the most difficult aspects of reading a floor plan is deciphering the symbols and abbreviations used. There are no universal rules for the architect when applying these symbols to the plans, so it's common to see different sets depending on who drew up the plans. Fortunately, there's usually a legend included to let you know what each abbreviation or symbol means. Look for this and familiarize yourself with the shortcuts used.

Parts Of A Construction Plan

When you receive your construction plans, you'll find a number of pages that each have a different purpose. A typical set of plans comes with these pages.

Cover Page

The cover page usually includes a drawing of the architect's vision for the project.

Title Block

The title block comes in three sections:

  • Identifying information for the plans, such as the title and number of the blueprint, site location, and whether that particular drawing is part of a larger set
  • Signatures and approvals needed for the plans
  • Any relevant references, including other construction plans used as inspiration for the project

Revision Block

The revision block is exactly what it sounds like. This is where you will find any new drawings created due to revisions to the original plans.

Drawing Scale

The drawing scale will give you any scale information for the various parts of the plans.

Key Notes

The key notes section will provide any relevant details the architect or engineer thinks the construction crews will need to complete the project. This can include clarification of important areas of the plans or site-specific rules that must be followed, such as noise ordinances in the local area or time restrictions for construction work.

General Notes

General notes provide short and concise technical information.


The legend will explain any abbreviations or symbols used within the plans.

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The Basics Of Floor Plan Measurements

Now that you've done your prep work and have a basic idea of what the finished project will look like, along with all the relevant overall project details, it's time to review the actual floor plans. It should be noted that most construction plans follow the same rules for displaying common elements of a structure, but it's still a good idea to check the legend in case there are any deviations from this standard.

Depending on the area of construction you'll be responsible for, you may need to become familiar with the plans of the entire structure or to isolate yourself to the relevant portions for your particular contribution. For example, if you're using the plans to prepare for laying carpet, it may not be necessary for you to focus on the details of the kitchen, garage, or bathrooms unless those areas are included in your contract. 

On the other hand, if you're a painter and want to estimate the amount of materials needed for the project, you'll need to know the wall measurements, ceiling heights, and measurements of any windows or doors that will reduce your surface area. Plans will sometimes come with multiple renderings of the same area of a structure meant for different trades. Mechanical, electrical, and plumbing drawings, or MEP, are a common inclusion used only to illustrate relevant measurements and areas of interest for these professionals.

Walls, Doors, & Windows

When looking at the ceiling floor plan, thick and solid lines are generally used for any walls on the interior or exterior of the structure. Breaks in these lines are used to symbolize doors and windows.

Doors are often displayed as though you're looking at them from the ceiling while open. This is to suggest the direction the door must open when installed.

Windows can be displayed as empty rectangles along the wall line or small line-breaking marks. If the measurements for these elements aren't included on the image, check the plans for a schedule that provides these details.

The Roof

Plans will also include the roofing lines, which can usually be found on the relevant floor of the structure. If you're working on a multi level building, you may only find roofing lines on the garage or covered patio of the first floor draft. The rest of the roof dimensions will be covered on the level meant to be covered and are typically symbolized as a dashed line set where the eaves would hang outside the exterior walls of the building.

Detailed roofing plans will show the entirety of the roof as it relates to the structure and will include ridgelines, hip lines, and valley lines to represent the intended shape.

Ceiling Height

Wondering how to show ceiling height in a floor plan? Sometimes the ceiling height of a given room can only be found on a reflected ceiling plan, or RCP. This is provided to show any relevant ceiling information, such as materials needed and measurements. It's drawn to look as though you're looking at the ceiling from its reflection through a mirror on the floor. If this sheet isn't included, architects will often show the ceiling height on the floor plan using an oval with a measurement for each room.

Stairs, Counters, & Other Elements

Stairs are represented by a series of rectangles that show the measurements of the staircase until it breaks through to the next level. Any counters or shelving included will be labeled and are sometimes shaded to set them apart from the wall lines. Fixtures, such as toilets, sinks, and bathtubs, are easy to spot because they generally look just like the element they're meant to represent.

Who Needs This Information And Why?

Most construction professionals and tradespeople can benefit from understanding how to read construction plans. General contractors, framers, carpenters, painters, plumbers, and anyone involved in new or remodeled construction will find useful information pertaining to their contributions.

For the build, the use is pretty standard. The floor plan provides the exact measurements needed for the structure to maintain maximum integrity for the design. These numbers are used throughout the build to give each professional on the site confidence in the measurements of the previous subcontractor.

Mistakes between these moving parts can alter the quality of the finished build or cause significant delays as adjustments are made to either repair or accommodate inaccurate measurements. This is why it's so vital for each subcontractor to understand how to read construction plans confidently.

The structure's erection isn't the only area aided with floor plan blueprints. Before even stepping foot on the site, some professionals can use the plans to create a realistic budget estimate when discussing a possible contract with the client. For example, knowing the floor plan measurements and ceiling height can help a painter estimate the square footage requiring coverage and the amount of paint needed to complete the project. The same estimations can be made for roofing materials, carpets, tile, and any other materials needed for the structure.

Additional Resources For Floor Plan Measurements

Even the experts still need to brush up on their floor plan comprehension skills now and again, so here are several places where you can get additional help when you feel you need it.

Symbols & Abbreviations

There are literally hundreds of symbols and abbreviations that are considered standard for structural drawings, and those don't even include the unique symbols sometimes preferred by certain architects or engineers. Although plans will come with a legend specific to the symbols and abbreviations used, it always helps to brush up on the basics so you start out with a solid idea of what you're looking at without having to learn every symbol on the fly. Check out this comprehensive list of symbols you're likely to see.

Floor Plan Software

Another great way to better understand floor plans is to play around with creating them yourself. There are a variety of open source software or free programs you can use to familiarize yourself with the anatomy of typical floor plan. Wondershare EdrawMax offers a free floor plan maker for your PC, as does Planner 5D. Both are meant for beginners and can help you learn by doing as you use all the available elements to create your own floor plans. There's even the Floor Plan Creator app for Android or the Floor Plan App by Laan Labs for iPhone users.

Take A Class

There are also a number of free or paid courses online that specialize in teaching students how to read construction plans. These courses can be as simple or detailed as you need. Some offer just a basic overview and can be completed in a day, while others offer a more comprehensive knowledge set and require more time to get through. You can also find detailed instructions on reading floor plans and blueprints on local and state government sites or find information at your local university.

Lay Your Professional Foundation

Taking the time to really understand how to read floor plans can reduce work errors, saving you time and money. Fewer mistakes lead to a stronger professional reputation that will help your career continue to grow as you produce quality and timely work. It's worth putting in the effort and learning more about floor plans and how they can help guide you through successful project completion. Like anything else, the more time you spend working with floor plans, the better you'll get at using them to your advantage to establish more satisfied clients.