Floor plans are the primary representation of a house. Plans are used to describe how spaces are positioned in relation to each other, the proportions and sizes of the spaces, and the components that make up a house such as walls, doors, and windows.
Though floor plans are common, most people have challenges understanding how to read plans and comprehend how they relate to an actual built house. Below are 20 things to understand about plans.
Plans represent rooms in a house as if the house were shrunk in size.
Though this one is obvious for many people, a floor plan represents a reduced-size house. This shrinking maintains the exact proportions and relationships of all rooms, walls, and other components of the actual house.
Floor plans are drawn as if the house is cut horizontally about 4 feet above the floor.
In order to show elements that don’t reach the floor and to represent important horizontal surfaces above the floor, plans are drawn as if the house has been cut open 4′ above the floor. This allows items such as the following to be shown:
- Windows
- Countertops
- Plumbing fixtures such as toilets and the sinks that are installed into countertops.
- Appliances such as washing machines and clothes dryers.
- Power outlets, both those close to the floor and those raised above countertops.
- Furniture when added to a floor plan.
The primary features represented in a floor plan are walls.
This is commonly known, but it states a bigger picture of things. Walls are what define spaces, as each of us know by living in a house or apartment. A floor plan uses its most prominent lines to represent walls in order to get a good overall view and understanding of a house and its spaces.
Floor plans are drawn such that all walls are projected onto a flat plane.
Though we state that plans are drawn as if the house is cut 4 feet above the floor, plans are actually projections of all of the walls and elements you’d see below the 4 foot height down onto a single flat plane – the paper image or computer image of the plan.
To better understand this, look at one wall in the room you’re in. Because our eyes see in three dimensions you see not just the wall but portions of the walls to either side of it along with portions of the floor and ceiling, creating a limited view we call perspective. Though perspective is how we see and perceive spaces in real life, it would be hard to see a whole house from a single view inside one room, or to figure out the actual size and shape of each of those rooms.
To overcome this, plans were created to represent the whole house, including all rooms and spaces, their actual proportions, and their actual sizes. To do this plans essentially take the house and squish everything straight down onto the “floor”. It then shrinks that down to a size that you can easily see to understand the whole house.
Plans drawn by hand are drawn at a common proportion to the actual house, called a drawing scale.
Once the whole house has been shrunk in size, we still need a method of measuring things. We need to know how long a wall is, where doors and windows are located, how deep and how long countertops are in the kitchen, and the placement and sizes of everything else you’d see in a house.
To do this we developed a long time ago a method to draw plans at an increment we can measure. This is called a drawing scale, and represents a proportion of the actual size of the house.
Common increments to draw plans use fractions of an inch to represent a foot of length (Imperial Units) or a centimeter to represent a proportion of meters of length (Metric Units), where “1 centimeter equals 1 meter” is stated a”‘1:100″ since a centimeter is 1/100th of a meter.
Plans created using computer programs are drawn at the actual size of the house.
Computers are not restricted to using a drawing scale. In a computer drawing program you’re actually drawing full scale, meaning 10 feet of length in the computer is 10 feet of length in reality. This simplifies drawing because you don’t have to convert to a scale.
However, if you’re printing a drawing from the computer that you want to measure you’ll need to print out at a drawing scale. This represents the actual shrinking of the house down to a scale.
Though drawing to an actual size is easier in a drawing program, learning to use a drawing program, especially one that creates buildings three-dimensionally, takes a lot of effort to learn in addition to the cost of purchasing such a program.
Plans use lines and symbols to represent things that are installed as part a house.
Whether you’re drawing by hand or using a computer, plans use lines to represent elements of the building.
A thick line or two lines drawn close and parallel to each other is often used to represent a wall. Thin single lines are used to represent things such as countertops and vanities, steps on a stair, the edge of a porch, or furniture in a room. Doors that swing open use a combination of a line for the door and an arc line to represent the limits of the door swing. Windows are shown as a series of lines within a wall.
Elements to be installed into a house, such as sinks, showers, bathtubs, and mechanical equipment, use special symbols that use a combination of lines to form their shapes and sizes.
Plans use dimension lines to locate elements in relation to each other.
To note the actual length of something or the width and length of a space inside the house, floor plans use a series of lines together with a measurement number. This is called a dimension line.
You’ll sometimes see a long line with multiple measurement numbers. This is called a dimension string and is used to show the placement of several things within a wall or several things to be placed in relation to each other.
Dimension lines are a great means to let you know how big something is and tells a contractor where things are to be placed in relation to other elements.
Plans use notes to describe elements of the house.
To describe components of a house, plans use written notes that are then tied by an arrow line pointing to what is being described.
When plans have a lot of items in them that would make noting everything by words challenging, we use a system called key notes. Key notes use a symbol in which a number or letter is placed. This number is then used to identify a specific note that is part of a group of notes located outside of the plan.
Square key notes with numbers are general construction items tied to specific notes listed elsewhere on the plan sheets.
Diamond tags with letters indicate various cabinetry pieces (millwork).
Triangle tags pointing left indicate miscellaneous items to be installed such as grab bars, mirrors, or medicine cabinets in the bathrooms.
Triangle tags pointing right with an additional vertical line represent plumbing fixtures such as sinks and bathtubs.
Triangle tags pointing down with an additional top line indicate appliances.
Circle tags with letters or numbers indicate doors of various types and sizes.
Hexagon tags represent windows of various types and sizes.
Plans use tags to represent components in the house.
To identify the different types of elements such as plumbing fixtures, along with the different sizes of common elements such as doors and windows, plans use tags to identify them. Tags are similar to key notes; however, tags are used a bit differently
For example, tags used for plumbing fixtures represent a particular component, such a sink, that identifies a specific sink that would include its manufacturer, the model, the model number, and its size. if there are multiple sinks of the same model and size, such as sinks in multiple bathrooms, the same tag is used.
Similarly, tags are used for doors and windows to differentiate their types (swing or sliding door; casement or double-hung window) and their various sizes.
There are many types of plans that can be used to describe a house.
Though floor plans are the most common type of plan, we often use specialized plans to represent various systems and components or special features of a house. These types of plans are typically used with more complex designs. They’re also used when such elements are hard to show in the floor plan due to the amount of items needed to be shown, which could cause visual congestion if shown on a single plan.
Floor plans show the primary elements of the house and where they’re located.
If there are multiple plans, floor plans will show the primary elements of the house along with their notes, tags, and dimensions. These elements would include walls, doors, and windows, along with stairs and cabinetry.
Ceiling plans are floor plans with everything in the ceiling projected down to the floor.
Ceiling plans are used to show what’s up there. The basic floor plan described above is used as a base, but without the notes, tages, or dimensions that go on a floor plan. This offers a “clean slate” for the ceiling plan.
Ceiling plans are used when houses have a lot of ceiling features such as vaulted ceilings, light coves, decorative beams, air registers, and light fixtures such as recessed downlights (recessed ‘can’ lights), wall washers, cove lighting, and such.
An advantage of a ceiling plan is that you can dimension, tag, and note all of these items without the clutter of the general floor plan.
Mechanical plans are floor plans that show components of heating and cooling systems.
Though not used for most houses, a mechanical plan is used to indicate where mechanical equipment is to be located and how ductwork is to be routed through the house. Such a plan is good to have when the floor plan would be visually congested with this information and when complex systems are to be used.
This plan would use tags, dimensions, and notes as needed.
Plumbing plans are floor plans that show plumbing fixtures and piping.
Another plan not used often for houses is a plumbing plan. This plan would highlight the plumbing fixtures shown on the floor plan, tag them, and then add notes and dimensions as needed. It’s also used to show primary equipment such as water heaters and softeners along with showing how piping is to be routed across the house.
Electrical plans are floor plans that show power outlets and other electrical and specialty components.
Electrical information for houses is often shown on the floor plan. However, when the house is complex or there’d be lots of visual congestion on the floor plan, an electrical plan can come in handy.
An electrical plan would show all power and specialty outlets located on the walls, wall switches for light fixtures, as well as the light fixtures (even if shown on a ceiling plan). Outlets and switches would be dimensioned, and light fixtures would be tagged. Also shown would be electrical service panels and specialty equipment locations for security or home automation systems.
Floor finish plans show flooring materials and unique patterns on the floor.
Floor finish plans are typically used in larger and highly detailed houses. Floor finish plans would show what flooring material is to be used in each space, where the transitions between the materials is to occur, and any patterns to be created when the materials are installed.
Example of patterns could included different colors of stone and special forms to be installed in a stone floor, and different wood floor materials such as plank and end-grain block flooring, and patterns such as herringbone, border designs, and insert patterns.
Floor plans can use symbols to reference other drawings.
It takes a lot of drawings and drawing sheets to show everything that goes into a house. Methods have been developed to indicate on a floor plan where these other drawings are located.
The most common symbols reference the following:
- Drawings, called elevations, that show vertical features of the exterior faces of the house and features inside rooms such as kitchen cabinetry.
- Drawings, called building sections, that show a vertical cut through the house to show the heights and relationships of rooms and floor levels and the structure of the house.
- Large-scale drawings, called details, that show close-up views of different elements of a house and how they’re put together or placed in relation to other things.
The reference symbols are based upon a sizable circle divided in half by a horizontal line. The top half has a number or letter inserted representing a drawing number, and the bottom half has a number listing the sheet that drawing is found on. Elevation and building sections also have an arrow showing the direction of the view that drawing has.
Floor plans are the first things created to design a house.
The importance of plans cannot be overstated. Plans are the first things that are created when designing a house, and are the basis of the overall form of the house in three dimensions.
Floor plans are refined in stages from initial concept to construction documents.
Because all houses have some level of complexity, floor plans have to be developed from a simple idea to ever more refined plans showing the design. These are then developed further into the complex drawings used to build a house.
These stages essentially work out as follows:
- Concept Phase: This is when initial ideas are toyed with. Before actual floor plans are even created, these ideas are developed using loose circles or rectangles to play with various ways of combining and placing spaces.
- Schematic Phase: This phase is when the overall idea, called a scheme, has been selected from the concept studies and the first development of an actual plan occurs. This is also when the first studies of the building form occurs, beginning the development of the exterior design.
- Design Development Phase: Design development occurs when the schematic plan and exterior form and general design have been established. This is the phase when you decide what all goes into the house such as cabinetry, the various systems, materials, and the components such as doors and windows. These are placed in the plan and you then figure out how everything works together.
- Construction Drawings: These are the drawings used to get a building permit and to build the house. These are the drawings that have everything drawn, detailed, tagged, and noted.
That’s the 20 things to know about floor plans. Plans are fascinating things, as they’re the basis of our understanding of houses.
All graphic images are by Cayl Hollis.
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