Construction Blueprint Symbols: Insider Cheat-sheet

reading construction blueprint symbols

Construction Blueprint Symbols You Need to Know

Why does it matter when you are building an ADU?

7min read
by Olesia Chikunova, ADU Specialist.

construction blueprint on site

A Blueprint and Construction Blueprint Symbols: What Are They?

Planning to build an ADU or a tiny house? It will be an exciting process from day one to the day of the big reveal. And the reward? A small space of your own! 

But, undeniably, it makes for an equally stressful and overwhelming project. Especially if you need to familiarize yourself with the critical terms and symbols of the building-construction industry.

In fact, one of the fundamental parts of building your small house is learning the various construction blueprint symbols before you submit for a permit. These make sure you have a smooth construction project with little to no headache down the line.

This article is your comprehensive step-by-step guide on construction blueprint symbols. You will know all about them before starting your project. So, let us delve into the world of shapes, dimension lines, and annotations!

dimensions in blueprint construction symbols

What Does 'Symbol on Blueprint' Mean?

A blueprint is an incredibly detailed two-dimensional drawing of your construction plan. It visually represents how an architect (or planner) wants the end structure to look. This blueprint is an essential part of home construction plans because it is later used to request permits and determine the schedule for the project.

It also guides the entire construction process, so it’s worth ensuring your blueprint is carefully curated. And step one to doing so is being well-educated on the various construction blueprint symbols used in architectural drawings.

In simple terms, construction blueprint symbols are miniature drawings/shapes used in blueprints. They often represent objects in the construction plans and, at times, denote functions and entire systems. They are utilized in various construction drawings, for example, architectural, structural, and electrical drawings. These are different types of blueprints.

However, you can expect a symbol legend on a specific page to guide you through each drawing. 

Every complete set of blueprints starts with a Title Block that reflects key information about the property, the team who worked on the construction blueprints, and relevant building codes. Depending on the city, you may also need to provide some calculations on floor areas or hardscapes.

Make sure your city is mentioned on this page rather than something that got carried over from a different project. 

Below, we dive into the details of construction blueprint symbols used in various drawings (or plans). We’ve handpicked the most useful categories of blueprint symbols for your small house plan. Be sure to go through them thoroughly before getting started! And definitely, before you sign off on your design.


Site Plan

When building your tiny house, you must first propose a site plan. This displays all the existing structures on the site and the improvements/new changes you plan to build. As a part of your site plan, you will come across the following symbols:

North Arrow

A common symbol used in site plans is the North arrow. This symbol indicates the placement of the structure in relation to the true North direction. Typically, it is positioned in the corner of the page, most likely near the title. 

The purpose of using the North arrow is simple; it helps viewers understand how your tiny house will be positioned on the site. This is particularly helpful when working around sunlight and wind directions for your home. Additionally, it shows how various elements within the building will be aligned. So, when you collaborate with engineers and landscapers, everyone will be on the same page in terms of orientation.

Avoiding a lot of windows on the South side will let you spend less money on cooling the house during the summer months.


The power meter, gas meter, and water meter need to be marked on the plans. Planners from the most important departments will check your building plans: planning, public works, and building. Every plan checker will look for the information on where you are connecting to the utilities and if lines and structures are far enough from each other. It helps avoid additional re-submittals if you include relevant information on the first submittal. How many Amps is your main panel? What is the size of your water meter?

electrical plan - blueprint construction symbols

Electrical Symbols

Electrical symbols graphically represent the major electrical components you will use to construct your tiny house. These include various devices and connections in your small house’s electrical systems. 

With these symbols, competent electrical drafters can effectively communicate the layout of electrical elements in your plan and show the plan checkers they follow the building codes. For example, where the electrical wiring goes, the precise positions of lighting fixtures and switches, and more.

Electrical plans should include appliance symbols and reflected ceiling plans to show recessed light locations. ADUs will be all-electric, which means your electrician should know what size of breaker every appliance will need at the rough electrical stage – before the drywall goes up. 


Also called the receptacle outlet, this symbol represents the areas you’ve designated for accessing electrical power in your small house. That is where you plan to position sockets for inserting plugs of electrical appliances. While there may be a variety of outlets, the two main ones are:

  1. A standard electrical outlet used widely across the house
  2. A ground-fault circuit interrupter (GFCI). This one has a circuit breaker that helps prevent electric shocks. So, you’d position the GFCI symbol near places using water, for example, the bathroom or kitchen.


This construction blueprint symbol shows a switch’s presence (and functionality). There are various types of switches, typically classified based on their functionalities. For example, a single-pole vs. double-pole light switch. The former is used to control lights and other basic electrical connections, while the two poles of the latter mean it can control two different circuits simultaneously. The one to choose depends on the electrical load you aim to control.

Do you want to be able to switch off the ceiling light when you are already in bed? It should be reflected in your electrical plan. Do you want to be able to switch off all the lights before you leave the house? That, too, should be reflected in your electrical plan.


An electrical panel is basically a distribution board. This houses the protective devices of your small house’s electrical setup, such as circuit breakers and fuses. The panel distributes electrical power throughout the circuits of your small home.

Lighting Symbols

Another essential part of construction blueprint symbols are those associated with lighting. These usually indicate the lighting you will use in your tiny house and where you will mount it. For example, ceiling light fixtures (mounted onto the ceiling), wall light fixtures (attached to the wall), and recessed light fixtures (recessed into the ceiling).


Plumbing Symbols

toilet and sink in blueprint construction symbols

Because apt plumbing ensures clean water is accessible in your tiny house, plumbing symbols play a major role in your blueprint. These symbols typically refer to the placement of plumbing fixtures, piping, and valves in your house plan.

The plumbing drawing should also reflect the slope of a pipe. If there is no slope, you may be required to install a pump, which must also be in the drawings. Below, we’ve listed the top plumbing symbols you may encounter during your construction plan:

Sink and Toilet 

These symbols reflect the positions of these fixtures in your ADU. Both symbols are represented mainly by ovals, with other little variations. Other fixtures that may be in your small house plan are the bathtub or shower and, at times, the bidet.


The cleanout symbol is considered when cleaning or maintaining your plumbing system. It represents a point of access that may later be referred to. For example, if you have a blockage, the plumbing team may use the cleanout point to inspect and clear the problem. It is required to have one on the outside of every house, and if you have a longer distance to the main sewer line, you may be required to have more than one.

Water Heater

The water heater construction blueprint symbol denotes the type of water heating equipment in your tiny home. It is important to specify its location during the early planning phase so it is fully functional when installed. The straight line will represent the cold and warm water supply in blue and red, respectively.

Modern small buildings require a water heater heat pump, which takes up floor space. It needs to be planned for early on – to ensure there is enough space for everything else in the bathroom or kitchen.


Several symbols indicate the piping and connections in your plumbing system. 

If your main house has sprinklers, your ADU will also be required to have sprinklers. In this case, your plans will include the type of underground pipe that can be used.

construction blueprint symbols

Architectural Symbols

Last but certainly not least, we have architectural symbols. These are larger and are typically the first to be drawn into floor plans. Many different aspects come under these architectural symbols, from the walls and doors to the stairs and rooms. Some are easier to understand than others. Furniture symbols are easy enough for most people. 

Exterior Wall Composition

The exterior wall composition holds material symbols – information about what your home’s outer walls constitute, especially their materials and layers.

Elements such as solid or dotted lines and shading indicate the layers. And learning about them is essential for understanding the structure and finishes of your house! Exterior walls are denoted by thicker lines than interior walls.

Windows and Doors 

The construction blueprint symbols for windows and doors typically represent the type and size of these fixtures in your tiny house. These will reflect differences in the windows or doors. This is an excellent time to consider the types of doors and windows you prefer.

Do you even like using casement windows? Would you like double doors for entry? Should the closet be behind the pocket door or bifold doors? These door symbols will later tell your construction crew how to frame the rough opening for an easier installation.


There are also different categories of these fixtures. Your designer should mark up egress doors and windows. They represent doors for emergency exits. Another example is tempered glass windows, which shatter into small, rounded pieces. These are used where there is a high risk of breakage and for safety reasons – think bathrooms and windows close to doors.


Floor Plan Symbols

Floor plan symbols indicate the components that define your small house’s layout and floor plan. For example, the stairs, rooms, bathrooms, and HVAC systems. These may also include symbols depicting the furniture, such as where the bed will go in your small house and how you will arrange the dining set and sofas in the living area. Have you asked for the kitchen sink to be by the window? Make sure you find it on the plans before signing off.

Structural Symbols

The structural drawing of your small house will communicate information about its framework and supports. It also tells you essential information about load-bearing structural elements. 

Structural symbols include foundations (thick solid lines), footings (rectangles), and beams. The foundation and roof plans are typical drawings a licensed structural engineer prepares.


Final Words

So, there you have it! Now you know the construction blueprint symbols you will use (or come across while examining) your small house plan. While these may vary slightly based on regional standards, you can get a basic idea here. If your blueprint still has symbols you’re not well-acquainted with, ask your designer to add them to the legend provided with your blueprint.

Happy tiny home building! 


small ADU in 3D and construction drawings

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