Should I build my addition up or out?

You know your home needs more space, you just aren’t sure where to put it. Home additions are large-scale, time-consuming, and expensive renovation projects. That’s why when you do it, you want to make sure to do it correctly. One of the first things to decide when planning a home addition is whether to build up or out.

As one of Portland’s leading remodelers, our team at Lamont Bros. knows all about the challenges that come with planning and building an addition. Many homeowners have questions about whether to build their addition up or out. Having worked on both types of projects, we know how to help you identify which is best for your home.

In this article, we’ll discuss the benefits and challenges of building an addition up or out. Once you’ve read it through, you’ll have a better idea of which option best meets your needs. Here’s what you can expect to read about:

Up or Out: What’s the Difference?

When building a home addition, the two most popular locations to build are on the side and on the top of the home. Both types of additions can be great design solutions depending on the goals of the homeowner.

Building Up: Second Story Addition

In a second-story addition, you add an additional level on top of your existing ground floor. These are popular projects for homeowners who want to add space to their home without increasing the size of its footprint.

Second-story additions require removing the existing roof and framing a new floor, walls, and roof on top of the home. They are often among the most expensive types of home addition projects.

Most homeowners use a second-story addition to add extra bedroom and bathroom space. Home offices and media rooms are less common, but still popular choices.

Building Out: Ground-Level Addition

Considered the more traditional approach, ground-level additions attach to the side of the structure. These types of projects are most common among homeowners who want the most cost-effective way to add square footage to their home.

A ground-level addition requires an entirely new foundation, framing, and roof structure. This often involves excavation in the yard, but requires less demolition to the actual home than a second-story addition.

Ground-level additions tend to be very versatile and can be used for nearly any room purpose. Bedrooms, bathrooms, garages, offices, home gyms, and hobby rooms are all common examples.

Things to Consider when Deciding to Build Up or Out

The current state of your home and property is going to have the most impact on whether you build your addition up or out. Here are several factors to consider when deciding where your addition will go.

How old is the house?

Home additions are challenging no matter what. Home additions to older homes can be even more difficult. This is especially true when adding a second-story addition to an old home. Often, homes built in the early to mid-1900s are difficult to build on top of due to structural concerns.

Older homes are also more likely to be protected by historic preservation laws, which limit what types of changes you can make on certain homes. In these cases, it is often much easier to add to the side of the home rather than build a second story.

Narrow land lots make it difficult to build out.

How large is the lot?

The lot size is a critical consideration when deciding whether to build up or out. If you opt to build out, your property needs to have enough space available.

However, in several urban areas, like the Laurelhurst or Irvington neighborhoods in Portland, lot sizes are usually quite small. In other areas like the Forest Hills, land lots often have steep slopes, which can limit access and land usability. This lack of space can make it challenging to build out on either side of the home.

Additionally, setback laws may prohibit additions on the front or back of the home. In cases like this, building up is pretty much your only option.

Does the existing structure need to be upgraded?

When planning a second-story addition to a home, it’s crucial to ensure that the lower floor is strong enough to bear the weight of the new story. If the lower floor is not strong enough, it may require structural retrofitting to support the additional load.

Structural retrofitting involves adding support to the existing foundation, walls, and floor framing to increase their load-carrying capacity. You may have to replace all of your siding and sheathing to increase the home’s shear strength. In other cases, you may have to underpin your foundation footings or reinforce floor joists. As a result, retrofitting the lower floor can be a substantial portion of the overall project cost for second story additions.

This is why it’s often more practical to add to the side of the home if space allows. Ground-level additions typically require fewer modifications to the original structure of the home, making them a more cost-effective option.

How will you access the space?

Adding any type of home addition, whether it’s a ground-level or second-story, necessitates access points from the original structure.

In a ground-level addition, the access point will typically be a door on what used to be an exterior wall. The placement of this door will impact the flow of foot traffic and the utilization of the rooms adjoining the new addition.

For a second-story addition, access can be more challenging. Since reaching the second story involves using stairs, you need to determine where in your home to install the new stairs. The issue is that a stairwell can take up a lot of space. As a result, it can be difficult to identify the best location for it in a house that was not originally designed to have stairs.

How much foundation work will the project require?

Consider the cost of foundation work when planning a home addition, whether it involves pouring a new foundation or fixing an existing one.

If you choose to build out, keep in mind that a new foundation will be required for a new addition. This process is usually simple if the lot is level and easy to excavate. However, if the lot has a steep slope, the foundation will require more engineering and concrete work, which will increase the cost.

Building out requires pouring a new foundation for the addition.

A second-story addition may not directly rest on the foundation, but the foundation must still support its weight. Depending on how it’s designed and the existing conditions, your home may need little to no foundation work before adding a second story.

However, in other cases, the current foundation may require significant repair or even replacement. This is primarily a concern for older homes that were built in the early 1900s when foundation regulations had not yet been standardized.

Which Option is Best for Your Home?

As you decide whether to build your addition up or out, it’s important to consider how each option would fit with your particular situation. To help you make an informed decision, here are some reasons why you might prefer one option over the other.

You should build out if:

Your land lot has plenty of space — When it comes to building ground-level additions, your greatest limiting factor is your lot size. If you have a large enough lot that you can afford to build out and still use your property how you want to, this option makes a lot of sense.

You want the most budget-friendly option — Generally, a ground-level addition is the most cost-effective design option. This is because it usually requires only minor modifications to the existing structure, which allows the majority of the budget to be focused on creating the new living space.

Your home is not structurally able to support another story — If your existing foundation or framing requires significant reinforcement to support a second story, it is generally more practical to opt for a ground-level addition and avoid altering the current structure.

You should build up if:

Your property does not have enough space — If you’re in dire need of extra space but live on a lot with constrictive boundary lines, building a second-story addition is often the only viable solution aside from moving.

You have an opportunity for a great view — In some cases, adding a second story can offer a vantage point for a better view of the landscape. Since great views can increase home value, you could consider it an investment in your home.

Your current home does not require structural retrofitting — Structural reinforcement makes up a significant chunk of the cost for second-story additions. So, if your home’s current structure won’t need to be reinforced, a second-story addition may be more cost-effective.

Need a designer’s expertise for your home addition?

Now that you understand more about the difference between building an addition up vs. out, keep up your research! Check out the Additions Portfolio on our website to gather inspiration for your upcoming project.

If you’re nervous about designing your home addition, you don’t need to face it alone! Click the button below to schedule a free design consultation with a member of our design team. We’ll guide you through the process to design and build your next home addition, whether it’s up or out!