An architectural plan, or set of blueprints, is created by architects, engineers, and designers to lay out all the construction specifications of a house, such as dimensions, building materials, installation methods, techniques, and even the order in which these things must be accomplished.
The number of details that must be included in a complete set of blueprints is so large that architects reduce the information on the drawings to a set of standardized symbols and abbreviations in order to make the drawing easier to read and less cluttered.
For reference, every set of architectural drawings includes a symbol legend. If you aren’t familiar with a symbol, you will be able to find it in the legend. Floor plan notes give additional context for the building. For instance, the notes can clarify exactly to what point on a wall dimensions should be measured.
Most plans include symbols that are a combination of:
In order to fit all the information about a layer of a building onto a page, construction drawings and architectural drawings are drawn so that a small increment of measurement represents a larger increment. This means that the plans are drawn “to scale.” Every symbol on the legend is drawn to the same scale as the rest of the floor plan.
Scales vary in complexity, from the simple (1 inch = 1 foot) to the complex (3/16 inch = 1 foot). Plans are often drawn at 3/4, 3/16, 1/8, and other scales (in each case the dimension in inches here corresponds to one foot). The symbols are also drawn to scale so you will get an accurate idea of how elements of a room are configured in the space.
The scale is always shown on the same page as the drawing, either under the title or below an individual drawing. Keep in mind that scales can vary throughout a set of architectural prints, so check each page and use an architectural scale, or scaled ruler, to make sure you’re reading the print accurately.
Recognizing symbols is a first step towards reading a property’s blueprints. Learn everything you need to know about reading blueprints in MT Copeland’s online class, taught by professional builder and craftsman Jordan Smith.
Imagine a view of a home sliced horizontally about five feet from the ground and looking down from above. This is the way a floor plan is drawn, and it is designed to give you a detailed idea of the layout of each floor of the house. This is just one of the components of the complete set of blueprints.
The types of plan symbols you’ll find on floor plans include everything from doors and stairs to appliances, furniture, and electrical symbols.
Here are the six most common types of symbols you will find on floor plans (versus other types of plans).
The north arrow tells you about the orientation of the property. Builders and architects use “Project North” as a designation, which is different from the cardinal directions on a compass. This allows you to navigate through the house by using north, south, east, and west without having to know where due (magnetic) north is.
Stairs are customarily indicated by parallel lines with their measurements. In this case, we see that they are placed between a window (the triple line indicated by a diamond), and an interior architectural wall (the double line).
Doors, indicated in this plan with a numbered hexagon symbol, are drawn with a straight line indicating the door itself; the curved line shows which way the door swings open, to show architects and designers the amount of clearance they will have in the room.
A window is usually denoted with three lines, vs. a wall’s two parallel lines. It is also indicated with a numbered diamond, which shows which window it is on the window schedule. As you look at symbols such as the diamond for window, look for important abbreviations that describe it, such as EQ, or “equal.” This will help you understand the dimensions of what the symbols are describing. For instance, a C with an L through it is a center line, and describes that a window is centered, with equal distance on either side.
Walls are usually indicated with a single line for interior lines, and are drawn with thick, dark line weights, usually in double lines, to indicate exterior walls. As you can see on this plan, the architect has also given the length for each wall.
Appliances and fixtures, such as toilets, sinks, and bathtubs, are drawn to scale with a thin line, and resemble the item they symbolize. Similarly, the furniture in floor plans is drawn with a light line weight so you can quickly tell that it is not integral to the building. It’s placed there for reference so that anyone looking at the floor plan can understand how the rooms were intended to be set up.
Appliances and fixtures such as cabinets and the microwave are often drawn with a dotted line. The most pertinent information, such as walls, doors, and windows, are drawn in heavier weights, so your eyes will be drawn to them immediately.
Each of the components of the architectural plan will have its own set of symbols and notes. Architects and designers work with the floor plans, and you’ll also see exterior and interior elevations, and reflected ceiling plan (RCP). Here are the most common found on each type of print .
Other types of prints within the architectural plan include MEP, or Mechanical, Electrical, and Plumbing. They are usually delivered in a bundle on a separate drawing with the relevant mechanical, plumbing symbols, and electrical symbols. As a builder or framer, you’ll need to know where those systems will be routed so you can leave space for them to be laid in. The MEP drawings will show the location of physical fixtures and the routing of the lines.
Plumbing drawings reflect the complex piping and sewage routes for the building, and these are examples of symbols you will find on the plumbing plans:
Mechanical drawings reflect the heating, ventilation, and air conditioning (or HVAC) systems of a building. Here are some of the symbols you will see on mechanical plans:
Architects and builders draw reflected ceiling plans (RCP) to show the dimensions, materials, and other key information about the ceiling of each of the rooms represented on the blueprint. It takes its name from the idea that you are looking down at the ceiling as though there were a mirror on the floor reflecting the ceiling’s plan back to you. Here are common RCP symbols:
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