Reading Blue Prints: 101

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Blueprints are a graphic set of instructions on how to build a specific building. The name blueprint comes from an early copying process that generated a blue background with the drawings created in white lines. However, the copy process has changed, but the term blueprint stuck.

The instructions, or set of plans, are organized in a specific hierarchy for consistency. This hierarchy remains consistent for all building plans. The more complex building will simply have more pages of information. Generally, drawings are sequenced from overall basic information, progressing to more detailed information.

Let’s walk through what a typical set of house plans contains and talk about interpreting the information they present.

House Plans 101

Plans are two-dimensional representations of a three-dimensional building. They are called orthographic projections. They start with plan views, which look directly down on a building, and progress to elevations, depicting vertical information or side views of a building. The next depictions would be sections or cut-away views leading to greater details or more specific information.

A set of plans begins with a cover sheet. This is the only page that will not have a number. All sheets are numbered from one through as many pages as needed. The label for the cover sheet is typically ‘CS’.

Before we get into the nitty gritty Rosie offers some preconstruction considerations for your blueprints.

*Rosie Tip

• Order several sets of plans for your home. Designate one of the sets as ‘original’. Don’t mark on it for projects and never lend it out.
• Blueprints are especially helpful in the design phase. Take the time to step into the prints and live the lay out. For instance:

Does your home have places for refreshment? Professor Cal Straub Of ASU School of Architecture called it stations of beer and wine enjoyment. This is the time to build in those spaces to your floor plan and landscape for family posts of gathering spaces.

Here is a brief description of the information contained on typical pages or sheets in a set of blueprints:

Cover Sheet

• Location of the project. There may be a small street map.
• Owner information.
• Information regarding the building codes utilized.
• General Notes that address material specifications to be used in the building.

Site Plan

1. A site plan depicts where on a property the building is to be built, including the overall dimensions of the building’s perimeter, distances to property lines, and cardinal orientation (north, south, east, west).
2. If any grading or leveling of the ground is needed, the topographical information will be included here, depicting cuts and fills.
3. This is where you show the relationship to existing vegetation that needs to be retained or removed.
4. Utility connections and locations of underground or overhead lines are marked.

Foundation Plan

1. This plan will delineate the specific dimensions of the building’s perimeter.
2. The footing dimensions and their relationship to the stem wall are illustrated here.
3. On occasion, and with simpler structures, some foundation and stem wall details may be included on this sheet. These details will indicate reinforced steel (rebar), size, and specific locations.
4. Notes with general specifications typically reference structural components.

Floor Plans

The Floor plan is likely the most used sheet in the set as it is the mother lode of project information.

A single-story building will be on one sheet, and multiple upper stories will be on subsequent sheets.

• Every horizontal dimension will be on this sheet.
• Locations of all the walls in the building and the dimensions of where to locate them are here.
• Door and window size and locations, along with other built-in features, would also be depicted here.
• Each door and window will be numbered. These numbers create a schedule or list of each door indicating the size, type, handling (the way the door swings), and hardware requirements. Every window will also include its size, type, and any special information needed to order and install.
• Each room will be named and numbered. They will appear on another schedule or list to identify surface finishes, including flooring, wall texture, ceiling texture, and paint color.

*If space allows, typically on simpler projects, these schedules will be on the floor plan(s) for easier reference for the builders.

Other Plans

When framing becomes complex for floors or roofs, a framing plan may be on the sheet right after the floor plan. This plan shows the placing of all the joists, rafters, or trusses in the building.

Elevations

While floor plans tell us all the horizontal dimensions, elevations will tell us the vertical dimensions and how tall everything is. Typically, the specific elevation will be referenced by the cardinal direction that side of the building faces.

• Exterior elevations show us the sides of the building or what the outside walls look like.
• Information includes the height of ceilings, upper floors, roof configuration, and window and door heights.

  

• Depictions of exterior building materials will be shown here as well. The configuration of materials used as accents, such as a partial stone veneer, will be depicted on the elevations and vertical dimensions. Remember, the horizontal dimensions are on the floor plan. So, some cross-referencing will be needed.
• Interior elevations may depict unique aspects of the building’s insides. Kitchen cabinets are a typical example of interior elevation subjects. Bookcases, shelving, and entertainment centers can also be shown on sheets following the exterior elevations.

Sections and Details

These are cut-away views we mentioned earlier. Picture the three-dimensional building being sliced with a perfectly straight knife cut through the building, and one part from that cut is taken away. You are left looking at the exterior and interior walls, floors, ceilings and roof all in one drawing.

• Section cuts are taken from areas of the building to show specific structural relationships and give the builders more specific direction on how to build a more complex part of the design.
• Details are close cut-away views of sections that portray greater specificity as to how a part of the building goes together. These are structural details used to show specific attachment techniques and products.

  

• Details can also show architectural features that require greater visual and noted explanations.

After all these plans, elevations, sections, and details are done, there could be more plans to follow. Electrical plans depict the location of each outlet, switch, built-in light fixture, and major electrical appliance. Also, this plan will show how and where the power will be wired and where it enters your home. You may have special smart home wiring and devices included.

*Rosie Tip

• Preconstruction: It is vitally important to think through your electrical layout for every switch, receptacle and light fixture. But it is also doubly important to check your electrical layout after the rough in process is complete and before the final stage of construction. Rosie says he has never had a construction project where electrical layouts did not have to be adjusted. 

There you have a semester-long course that is about a twenty-minute read. Reading plans and applying the information takes time and practice. We hope this basic tutorial gives you some understanding of how your blueprints work.

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Homeowner Handbook | #ReadingBluePrints

PODCAST

February 22nd, 2025

Our Weekly To Do on reading blueprints. An update on a homeowner’s smoke detector saga finally solved. Mike Lowery of Phocus Insurance explains what a service line endorsement added to homeowners insurance policy can cover your water supply line, sewer and natural gas piping, electrical and other utility lines. Fixing a stucco leak and more!

Original Broadcast Archive Page With Expanded Content

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