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What Are the Most Important Design Considerations When Building a Home Addition?

Home additions are a fantastic way to add a little extra space and character to any home, but they require a significant amount of planning and work before they come to fruition. While it is important to consider common elements such as budget and timeframe when building a home addition, there is also a great deal of design elements you must consider as well, which we’ll discuss here.

Here in The Bay Area, design plays an important role in home additions.  Home owners typically do not want a cookie cutter design dozens of other houses have, but something personalized that is made for their specific needs.

When building a home addition, the most important design elements you should consider are:

  • Purpose
  • Building and zoning regulations/codes
  • Scale
  • Matching vs. individualized aesthetic
  • The seven elements of design

Starting with the right element will make the design process infinitely easier later on and ensure the addition’s safety.

In this article, we’ve listed five important things you should consider design-wise when building a home addition to ensure it blends seamlessly with the rest of the home while maintaining a unique character.


Five Things to Consider When Designing a Home Addition

A home addition’s overall design is what really gives it a cohesive aesthetic and makes it feel like a part of the original home rather than just a tacked-on space.

Designing any space is an extensive process that needs to start strong with a clear vision. Otherwise, its design might change multiple times throughout the addition’s construction, resulting in a confused aesthetic that might leave it feeling like a randomly placed section of the home. Even worse, it might not fulfill all of the homeowner’s desires in terms of visual design, functionality, and features.

A great way to avoid an aesthetically confused or underwhelming home addition is to consider the five design-oriented elements listed below before starting construction. They are:

  • Purpose: what is the addition meant for?
  • Building and zoning regulations/codes: does the addition follow all local rules?
  • Scale: how big is this addition, and how does it affect the purpose, features, etc.?
  • Matching vs. individualized aesthetic: is it cohesive with the original home’s design or visibly separate?
  • The seven elements of design: what visual design elements will you incorporate (ex. color, line, space, etc.)?

You should consider these vital design elements when creating blueprints, floorplans, and design boards for a new home addition. Together, they will help create a clear vision of what this space is meant to do, how it should look, and how it can fulfill all required needs with stunning but functional design.

Below, we discuss each of these five design considerations in more detail so you know exactly what to expect and plan for when building a new home addition.

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Before you can even consider the visual design or overall aesthetic of a new home addition, the primary consideration has to be the addition’s purpose. For example, is this addition going to be a new space for the home, such as a separate bedroom or space for entertaining, or is it being used to expand an existing room, like the kitchen?

Considering a home addition’s purpose will significantly affect its design in terms of blueprints, features, and floor plans to match its intended function and fulfill all homeowner desires.

Once you know the home addition’s purpose, you can use this information to determine what features are most likely to be placed within the space and how this will affect the design.

For example, if the addition is on the second floor directly above a ground floor laundry room, a laundry chute might be a desirable feature to add to the blueprint designs as a functional feature.

Another example would be if the addition is intended to be a library, it would be optimal to have recessed bookshelves designed into the walls. This will help the room feel more open and spacious without numerous bulky freestanding bookshelves taking up floor space.

It seems like an obvious consideration, but it can be easy to lose sight of an addition’s purpose when you start planning its minute design details. Therefore, have a clear vision of the space’s intended function can help your designs remain consistent and give you a consistent point of reference whenever its design seems to veer off.


Know What Building and Zoning Regulations Apply to the Home Addition

When people think of design, their mind usually goes straight to the seven design elements, which we’ll discuss a little later. Although a home addition’s interior design can certainly make or break a space in terms of wow factor, its appearance will mean nothing if the addition ultimately isn’t up to code and has to get torn down.

Once the purpose of a home addition has been established, it is important to be well-researched and knowledgeable about local codes so all future design features are safe and legal.

In order for the home addition to officially be up-to-code and increase the home’s overall value, a certified inspector, usually from the town or city, must thoroughly inspect the space and render it safe for inhabitants before it can officially pass.

Usually, a failed regulation would require the addition to be torn down or fixed, but there is a rare occurrence where a code violation isn’t deemed a safety hazard and, therefore, may be left as is.

Of course, this isn’t something you want to bet on as a designer, so it is best to create your plans will all local building and zoning codes in mind.

Common regulations designers should consider include:

  • Placement of beams and joists (must not support structural integrity)
  • Window well size (typically, width and horizontal projection must be at least 36 inches)
  • Presence of rescue openings/ emergency escapes
  • Handrail installation (handrails are required on every staircase, and all must have been returned)
  • Bathroom ventilation (all bathrooms must have exhaust fans that lead outside through the roof or side for ventilation)

If you start to design the addition with various features in mind that don’t meet or inhibit these codes, you’ll be strongly dismayed when an official inspector tells you all your hard work must be torn down to meet local code. This often comes at an increased cost to the project, which won’t please the homeowners.


Scale of the Addition

The final technical design element you should consider is the scale of the addition in terms of sheer size.

Considering the size of the addition will help you prioritize features and determine which design elements can and must fit into this space. A small addition will likely require a more minimalistic design to prioritize functionality, whereas larger additions give you more freedom.

Additions can be built in a wide range of sizes, so you’ll want to know what kind of space (or spaces) you’re working with design-wise to make informed decisions.

Some additions are simple bump-outs that add a little more square footage to one room. These are great for designing a walk-in closet or grand bathroom in a bedroom or a butler’s pantry for a kitchen. Alternatively, it could simply give the homeowner some freedom to completely redesign a room with the added space to make it more comfortable rather than adding unnecessary features.

Of course, some additions will add an entire room or even several rooms to a home. In these cases, you’re going to want to think seriously about this room’s design, considering the space you’ve been given and the room(s) intended purpose.

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Cohesive With the Rest of the Home or a Complementary but Individual Space

By this step, you can start considering the more creative elements of design regarding aesthetics and how the addition will look in relation to the rest of the home.

Typically, you’ll want to design a new home addition in a way that is consistent with the rest of the original house for an overall cohesive look. However, there are some instances where it benefits the addition of unique elements that set it apart from the rest of the house.

If the addition is a bedroom or a common living space, it is usually best to ensure the design allows the addition to blend in with the rest of the house rather than being a space attached to the original home.

You can do this by matching various design elements found in other rooms, such as color palette, frequently used materials (ex. stone, tile, carpet, wood), shapes (both decorative and structural), and more.

Nevertheless, some additions are designed to be a retreat or a space, unlike the rest of the home. In these cases, you’ll want to ensure the design reflects its purpose over prioritizing a design that ties in with the rest of the home.

Sunrooms are a great example of this. These spaces are bright and open, so inhabitants feel as if they are outside. If the rest of the house boasts a darker pallet and metallic features, you probably wouldn’t want to carry those over into the sunroom as they won’t match the nature-oriented focus of the room.

Instead, you should incorporate woods, light tones, and lots of windows into the room’s design to provide the right aesthetic.

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The Seven Elements of Design

Now we can get into the more satisfying part of home addition design known as the seven elements of design. When done right, incorporating and blending each of these elements can help you create a balanced but striking aesthetic for any room.

The seven elements of design include:

  • Line
  • Shape
  • Color
  • Value
  • Form
  • Texture
  • Space

Each is essential, particularly when creating a cohesive aesthetic for the addition that will help it either blend in with the rest of the home or stand out as an accent space. Let’s briefly discuss the importance of each, starting with “line.”


Lines within a home addition help a viewer’s eyes travel around the room and can significantly affect how large and spacious the room feels regardless of its actual size. If the addition has several vertical lines created by features such as a fireplace, windows, and doors, or even wood paneling on the walls, it will help the room seem taller than it is.

Alternatively, horizontal lines in structures like wooden beams, wall paneling again, or even a room with several shelves (like a pantry or library) will help the room feel wide and spacious.

The best thing you can do is follow and balance these lines, so a room feels tall and spacious rather than cramped and short.

Shape and Form

When it comes to design, form, and shape are rarely considered independently, so we’re going to discuss them together here.

These refer to the geometric shapes within the addition and the shape of the addition itself, and any shadows or other elements of dimension within a room.

You don’t want to think about the shape of addition by itself (although this is important to consider) but what you will fill the space with.

Shapes and form are what will fill out a room and give it depth. This is typically provided through furniture, light fixtures, and structural features, all with lines, shapes, and volumes.

Again, you’ll want a balance of these elements, so they help heighten the addition’s aesthetic rather than making the room feel like a confusing mess of shapes and lines.


Never underestimate the power of color, and don’t restrict it to the addition’s walls. You can incorporate color through furniture, blankets and pillows, and various features in the room in addition to the walls.

Not only does color help create a dominant mood in the addition, but it can also help aid your lines and shapes in making the room feel cozier or more spacious, depending on your design goal. For example, light colors paired with lots of natural light will make a room feel bright and airy versus a room filled with more relaxing hues, like blues.

Refer back to the room’s ultimate purpose and let this help guide your color scheme and refer to the dominant color schemes seen throughout the original home.


Value predominantly refers to the light (or lack thereof) in the addition and how this hopefully works for the room rather than against it.

Light is provided either naturally or artificially. Playing around with both in your design can help a room feel bright and energetic, calm and relaxing, or a mixture of both in much the same manner as color.

Windows and skylights are a great way to add natural light, while artificial light fixtures can be used when countless windows aren’t the optimal design choice. You can also provide more lighting options by giving opportunities for shade and shadows through light dimmers or window drapes.


Incorporating texture is another way to add some visual depth to a room without filling it with couches and other furniture or lining the walls with shelving.

Something as simple as a throw pillow with textured fabrics or decorative features placed on top of furniture can give that extra element of character to a room without taking up excessive amounts of floor space.


Arguably the most important design element is space because you want this addition to feeling navigable and usable rather than claustrophobic.

Space refers to the distance between various objects within the room. This might be between the walls and nearby furniture or the distance from one piece to another.

The goal is to balance a room’s positive and negative space (space where an object lies versus free space) to feel spacious without feeling empty or cluttered.


Final Thoughts

Although this is far from a comprehensive list of design considerations you should contemplate when building a home addition, they are the right place to start. Having a clear vision from the beginning through knowing the addition’s purpose, scale, and aesthetic will help with interior design decisions relating to the seven elements.

Plus, knowing the building and zoning codes will help you design features of the addition properly the first time rather than it failing inspection and requiring an entire remodel. Therefore, although it isn’t the most obvious design consideration, it is arguably the most important to the project’s success.

Ready to start your home addition project?  Element Home Remodeling is a Mountain View based home addition contractor that specializes in design build constructionContact us today to schedule a free consultation.

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