3D rendering of a hand scribbling technical details so the customer knows how to read a floor plan

Understanding how to read a floor plan takes some explanation (Photo credit: FrankBoston)

You’ve purchased your new home and are waiting for it to be built. During one of your meetings with the builder, you’re presented with the floor plan of your new home. But how to read a floor plan? What are you looking at, anyway? Is that line a window or a door? Is that round thing supposed to be a sink or a tub?

Your floor plan will give you a solid idea of where your home’s critical parts will be. But if you don’t know how to read a plan, you’ll likely be left with more questions than answers.

This article will give you all the information you need to read a floor plan. You’ll also discover what you can and can’t learn from your floor plan, how adjustments can be made, and how your local zoning and state building codes play into your final decisions.

Livabl spoke with Marilyn Moedinger, the principal and founder of Runcible Studios. Moedinger’s architecture firm has offices in Boston, MA, and Lancaster, PA. Runcible Studios has been operating since 2014.

How to read a floor plan and what can a floor plan tell you?

A floor plan can tell you the rooms’ arrangement, which is crucial. Unlike photos, which give you one view of a specific direction, a floor plan can tell you how the rooms relate to each other and the size of those rooms as they relate to one another. So, even if there aren’t any dimensions or labels, or sizes, you can see that the bedroom is much smaller than the living room, for example. That’s the kind of information you can get from a house plan.

You can also see where windows and doors are and how they line up with other things in less space. And usually, floor plans will also include things like where basic fixtures are, such as toilets, showers, or sinks in the kitchen and cabinets. So, it will tell you where those things are in relation to each other and to a scale meaning that it should be reflective of what’s there in reality.

What can’t a floor plan tell you?

A floor plan can’t tell you what things look like to your eye. Our eyes see in perspective. We see things in three dimensions; a floor plan is not how we experience space. So, a floor plan is a kind of map. Think about when you read a map — you don’t see all the hills, and you can’t see the buildings or trees.

Floor plans can’t tell you certain things, and you’ll have to look at the space in person to get an accurate idea. It may not tell you how tall the ceilings are or how the area might feel in terms of the light coming in because you don’t know where the sun is in relation to the actual rooms.

What are some critical elements of knowing how to read a house plan?

So, there’s some basic floor plan vocabulary that is helpful. If you understand how a door or window is drawn, they’re usually drawn the same way. Understanding the symbols for a door so you can identify it, and a door has that little swooping arc line. That tells you that the door can swing and the door’s sweep, so you understand the direction in which it opens.

Once you recognize those symbols, you can read all floor plans. The other thing to know about floor plans and reading them — they’re sliced at four feet above the ground plane. This is known as the “cut line,” which means whatever the builder is slicing through at that four-foot mark.

What’s a plan set?

A “plan set” or, more accurately, a “drawing set” is a set of drawings that includes plans, sections, elevations, details, and schedules that give the contractor a comprehensive set of instructions. One important thing to realize is that the floor plans, when part of a drawing set, are not actually for the owner. They’re for the contractor. Sets are a visual contract. The architect writes the visual contract between the owner and the contractor and says, “This is what the owner wants, and this is what the contractor is obligated to build.” It’s a visual contract. So that’s why they’re called contract documents. That’s the official title for them.

Once you understand that, you know that when an architect draws plans, they’re not drawing them for the owner. They’re drawing it to give instructions to the contractor. So that’s where there are dimensions of things that are for the contractor.

Many times, when you’re buying a home, there’s a simplified floor plan that’s often drawn. And sometimes, it’s from the architect’s drawings, meaning it’ll be pretty accurate. And sometimes, it’s drawn by a floor plan service or just by hand by the realtor. But that’s where things can get sketchy.

Being able to draw these drawings is a skill, and through no one’s fault, sometimes these simplified versions don’t always come out right. So, for buyers looking at simple floor plans that didn’t come from the architect, it’s always smart to print them out and take them to the showing or an open house. When you’re there, take a few measurements of your own and compare them to the floor plan. Make sure the way you’re looking at them is correct. If the floor plan says the bedroom is supposed to be 15 feet by 15 feet and your measurements tell you it’s 12 feet by 12 feet, that’s a huge difference. So, the architects’ drawings will always be accurate because they are contract documents. A realtor’s drawings are not held to that standard.

What elements of a floor plan can be changed if a buyer isn’t happy with certain features, like the placement of a window or door?

The real answer is that anything can be changed. It just takes time and money. With potential buyers and my clients, I look at a house with them and point out things like load-bearing walls. So, you can take them out, but we need to put in beams and columns for the sake of the structure.

I might say, “Yes, you can move that window. I agree with the contractor. Zoning allows it, and the building code allows it. But if you move it, you’ll totally kill the furniture layout possibilities in here.” So that’s where architects come in, thinking about those things holistically.

A buyer needs to understand who answers their questions and what answers they will get. If they ask their realtor. The realtor only sometimes knows all the subtleties of building code. And that’s okay; that’s not their job—same thing with contractors.

Sometimes with architects, they only know some of the subtleties of construction, primarily if they work much more on the design side. As a buyer, it can be tough. You might need to get all these opinions from different people or find someone like our firm. I used to be a contractor, and now I’m an architect, so I wear both hats. And there are plenty of people who do that well— they can be great contractors on design or architects with contracting or construction experience.

How do zoning and building codes affect floor plans?

Working in the Boston area, we have very strict zoning requirements. So even if it was easy from a structural standpoint, and we have a window that the client wants to move, we might not be able to do that because zoning says you can’t move windows on this facade.

There’s a series of things that you must check. If you talk to a contractor, they will look laser-focused at the problem to see whether you can do it. An architect will determine whether you can do it from a structural standpoint. And even then, they’re not engineers, so they don’t always know. An architect will be looking at it from a structural standpoint, a zoning standpoint, a code standpoint, and a usability standpoint.

There are two primary buckets of code: One is zoning, and one is building. Zoning codes are administered locally, such as in your town or city. I’m in Boston, but specifically, I’m located in Cambridge, next to Boston. Cambridge has different zoning than Boston. However, Cambridge and Boston are under the same building code. So zoning code is administered by the city or the township, and then building codes are issued by the state.

Most states take one of the uniform building codes, like the International Residential Code or the International Building Code. Then they amend it for the state. So here in Massachusetts, if I have a question about building codes, I get out my International Building Code Book, and then I get out my book of Massachusetts amendments. I must make sure that Massachusetts hasn’t enforced stricter guidelines.

That’s also why architects and engineers are licensed by the state, not by federal, because we are charged with protecting health, safety, and welfare. It means we must know the codes, which means we can’t be certified for the entire country because it’s 50 different sets of codes.

How often does an architect have to be aware of zoning and building code amendments?

Zoning changes can happen any time there’s a city council meeting. You must keep tabs on it because it can change at any time. So, in the jurisdictions where you work. You’re constantly keeping an eye on the city council. You’ll have to know when they’re meeting about an amendment and if they passed it. I wouldn’t say that every time they meet, they’re passing amendments all the time, but it does happen multiple times each year.

With building code, it varies by state. But generally, the state adopts a code, which starts on January 1, but everyone affected will have known about it since the previous year that it’s coming.

In Massachusetts, it happens every three years. They adopt the next version of the code, and those amendments are updated every three years. That being said, the state reserves the right to up to update the codes at any time, as well. That’s why we have code consultants on big, complicated projects. They help us ensure we’re handling all the little tricky stuff.

But on houses, it will depend on where they’re buying, such as New York, Boston, or L.A. —somewhere with many restrictions and codes. If you’re in a big city, it’s much more of a thing. It varies a lot depending on where you are. Some places are far less strict.

What are some of the questions an architect should be asking you about your custom floor plan?

If a buyer is working with an architect, they’re designing the floor plan with the architect, and the architect should guide them through the process. The architect should ask questions like, “What does Saturday morning look like for you? What about Thanksgiving dinners? Do you have in-laws who come to stay? Are you planning on having kids? Are the kids moving out of the house? How long are you staying here?” Everything that happens in your life is helpful to know.

If you’re building a custom house, the house is there to support your life. The architect must understand you, your life, and how you do things. People do certain things because they think they should, or that’s how it’s been done in every house they’ve previously seen. They may also be worried about resale value. If you’re building a custom house, you should do it the way you want.

So, for example, if you want the laundry machines on the first floor, and most people put them on the second floor, but if you want them on the first floor, it’s your house. It’s not the end of the world. Don’t be miserable in your own home. If you sell in 15 years, let them put the laundry upstairs or pick the tile they want. They’re likely to change it in 15 or 20 years, and you will also want to do so.

Don’t be scared. Don’t think about resale value for the next person. Don’t build your house for the next person; build it for yourself. No matter what happens along the way, that is super important.

What are some of the questions you should ask a mass builder about your floor plan?

When it comes to mass builders, you’re more restricted with your floor plan choices. It’s like buying a car, where you have three color options for the interior.

What would be more important in my book, if you’re working with a mass builder, is to understand the actual construction spec of what they’re doing. Are they using suitable materials? are they what are their framing techniques? How does the HVAC system work? How are they handling the plumbing? The stuff in the walls is unpleasant if it begins to go wrong. To me, it’s more important to understand these things.

If you’re being offered a bigger house plan for the same price as a smaller one, you need to ask questions about the savings because those costs could be coming from critical materials for your home.

Asking questions and gathering opinions

Your house plan shouldn’t be an indecipherable puzzle for you. Now you have the tools to read your house plan and, more importantly, ask critical questions about it. Be sure that your architect is up to date on all the building and zoning codes if you want something changed. If a real estate agent gives you a basic sketch of your home, double-check those measurements with the builder and the architect. Above all, remember that the house plan is ultimately a map, but the architect can guide your decisions on if it’s the correct map for you to follow by asking you lots of questions about your life as it is now and looking ahead.

To view a wide variety of house plans for purchase, visit houseplans.com.

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