Learning how to read blueprints for residential and commercial construction is essential for a career as a contractor.
In fact, whether you are seeking a career as a construction professional, a skilled sub-contractor, a tradesperson or you are a consumer with a pending new build or rebuild, learning to decode blueprints will ensure the best results for your project.
Check out our article below for an overview of the nuts and bolts of reading residential and commercial construction blueprints. For more in depth information, please check out our Blueprint Reading for Construction Trades course.
What Are Construction Blueprints?
When you think of construction blueprints, you probably think of those long rolls of paper that contractors (or television actors who play contractors) always seem to be carrying under their arms.
But blueprints can come in any shape and size. While some blueprints are enormous even when all rolled up, some sets of blueprints are letter-sized and bound just like a regular notebook.
The size of the plans themselves depends on the scope and type of construction project.
Most construction plans are still drawn to be two-dimensional, or 2-D. A 2D image is a flat image that relies on horizontal and vertical (X and Y) dimensions.
NOTE: Some construction blueprints are drawn in 3D using BIM (building information modeling) which is beyond the scope of this article.
In either case, the basics of learning to read blueprints you are reading here still holds firm.
What Does a Set of Blueprints Include?
The typical set of blueprints will include several components in this general order:
A rendering (drawing) of the completed project is usually included right on the cover page, which provides a visual context for the content.
The cover page includes details like the creator’s name, the date of creation, the date(s) of any revision(s), the copyright number, the plan number, the scale and the sheet number and total number of sheets.
The title block is typically located on the cover page or on the page immediately following. Location of the title block depends on the size of the plans and how much information will fit on each page. It often has a grid-like look to it – like a spreadsheet or table.
An important component of the title block is the blueprint name, number and set reference (if the plans are part of a greater set of blueprints).
It is easy to glance at the title block to see if the plans are complete by looking to see if there are any blank spaces in any of the blocks or cells. Blank spaces indicate plans still undergoing revisions.
Somewhere inside the title block there will be a place for signatures with approval dates. These will let you know the status of the blueprints.
If the blueprints have been revised, notes about each revision will be included in this section.
The drawing scale indicates the ratio of the blueprints to the finished product. This is important information because it allows contractors to find any missing dimensions.
The notes section services as a comprehensive place to review and discuss design related decisions and furthermore, ensure alignment on management of the overall project. This section can sometimes be used as a checklist for final plan approval.
The blueprint legend or key is where you will find the meaning of symbols and drawings for a given set of blueprints.
Why Do Blueprints Have So Many Sheets?
Blueprints are designed to be read and understood by professionals from a variety of different trades. So there will be at least one sheet for each professional involved in a given project.
Typically, blueprint sheets will include electrical, mechanical, civil, architectural, structural, plumbing, landscaping and more.
A list of all sheets along with their reference page numbers should be included on the cover page.This list is usually composed of both alpha and numeric characters to provide an index of pages within a given set of blueprints.
For example, you might see C-1, C-2, C-3 and then A-1, A-2, A-3. These designations tell you that the Civil plans have three pages and the Architectural plans have three pages.
Similarly, S-pages are for Structural plans. M-pages are for Mechanical sheets. E-pages are for Electrical sheets. P-pages are for Plumbing sheets.
What Are the Typical Stages of Blueprints?
Blueprints, like construction plans themselves, often go through a few iterations in their evolutionary cycle before they are complete.
Sometimes called “preliminary” plans, schematic blueprints are written primarily with the consumer’s and contractor’s needs in mind.
Schematic Blueprints typically address an initial set of questions such as:
What is the scope of the project?
What is the budget?
What will the completed project look like?
What are the various zoning and permitting needs?
Issued for pricing
This section is used to begin placing orders for supplies, labor and other items.
Issued for permits
This section is used to begin submitting for permits as needed.
Issued for construction
This is the final-final set of plans that will be used during the actual project.
What About Revisions, Changes and Corrections to Blueprints?
It is pretty rare for a set of blueprints not to undergo at least a few rounds of revisions before the final set is issued and approved.
However, juggling all of these revisions can quickly get complicated. You need to know exactly how many revisions have been done and what version of the blueprints you are holding in your hands.
To find this information look to the margins of any sheet for a small block that details all revision dates. If you see small bubbles or circles with numbers and letters in them, this tells you where to look inside the revision block to find the relevant corrected sheet.
When an individual sheet or section is revised, corrected or updated, this is known as an Addendum. Typically these updated sheets will be inserted just in front of the outdated sheet, which will then be dog-eared and marked “void.”
Are You Ready to Learn to Read Blueprints?
Anyone who works in the manufacturing or the skilled trades benefits from a foundation knowledge of understanding blueprints, whether seeking a new career path or improved job performance.
Thanks to today’s technology, learning how to read blueprints can be done online, allowing you flexibility and the freedom of self-pacing. Our Blueprint Reading For Construction Trades provides a basic overview of blueprint reading concepts. Written and vetted by industry professionals, this course is designed to give you the skills you need.