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Should You Build Up, Down, or Out When Adding Space to Your Home?

Knowing where to build an addition to your home can be an agonizing decision. And not understanding the impact your decision might have on the construction process (and your wallet) can make it doubly stressful. An architect can help you understand the best solution for your situation and help you move forward.

Jeff Pelletier

June 18, 2020

Maybe you’ve outgrown your house, but you love your location. Or maybe you know that you need more space and are wondering where exactly you could capture it. Do you build up, dig down, or pop out? All solutions have their pros and cons, so let’s explore the different situations where each scenario might be appropriate.

Are you thinking of building an addition up?

If you don’t have the room or zoning approval to build out, you might be able to build an addition up. Building a second-story addition can add a lot of value to your home. Any addition that you add upstairs will invariably have better light than what is below, and, with a view home, you have the option to move your living space to the second floor to enjoy that gorgeous view from your kitchen and living spaces.

While the vast majority of homes can handle a second story addition, that doesn’t mean it won’t come without challenges. It is going to require you to rip open some walls on the floors below, and potentially also deal with your foundation to meet the structural needs of the new floor. Plus, you’ve got to find a spot for a staircase to go that makes sense. This means you could be doing a partial main floor remodel, too. And, that isn’t cheap. There’s no getting around it, but if you love your location and a lot of your home, investing in building an addition up can make a lot of sense.

Pros of Building Up

• Added value to your home.
• Lots of light!
• Access to views.
• Good alternative when you can't build out.

Cons of Building Up

• Possible and likely upgrades to your home’s structure.
• Partial main-floor remodel required.
• High cost.

Curious for more about second-story additions? Check out our take on whether it makes sense to add a second story addition to your home.

Maybe you'd like to add more space by digging down?

When you don’t have room or the zoning approval to build out or up, you can often still build down. This means digging out or finishing your basement, and it can be a great solution for really tight lots — one reason why London is seeing giant mega-mansions being built below grade. If you don’t have adequate ceiling height, though, digging down can be very expensive and complicated. I live in a very tight urban lot and it was the only solution to get more space in my house, but that might not be the case for you!

One aspect of digging down to add space many don't consider is that you will likely need to dig up all around your home, which means plantings, patios, and decks may all need to be re-created after construction is complete. On the bright side, you won’t lose any yard space with the final product.

Unlike building up, any space you create in a basement will be darker than above. For this reason, we advocate for choosing finishes as nice as the rest of your house in a basement so it is integral to your home and doesn’t feel like a downgrade. This means it isn’t cheap to finish it out. But, you’ll create a lot of useful secondary spaces that might be just what you need for a hobby room or home gym. People feel bad about putting those spaces upstairs in “valuable” real estate, but less so when they go downstairs.

Pros of Digging Down

• A great solution for tight lots.
• Yard space is maintained.
• Perfect for secondary spaces you might not want on your main floor.

Cons of Digging Down

• Can be complicated and expensive if existing ceiling hight is inadequate.
• Tends to get less light than other additions.
• Yard is impacted during construction.

Perhaps building an addition out is right for you?

Building out means you can avoid touching the majority of your home, as the structure you will need to add will mostly be independent of the rest of your house. There are big exceptions to this rule but, overall, it is going to be easier than adding up. And you don’t have to deal with adding in a staircase, so building out is inherently accessible. Building out can be especially useful in a tight older home because adding on to the main floor can easily open up room for a larger kitchen or family room while keeping your living and dining spaces intact.

This will, however, take up yard space and, even if you have the room on your lot to do so, it means that you have a smaller yard. Additionally, you have to consider how the outside of the addition will look against the original house (there’s often a solution but it should be thought through carefully). Plus, you’re going to have to build a whole new foundation, floor, and roof, too. When you go up or down, you don’t have all those associated costs; so, even though this is likely cheaper than the other two options, that isn’t always a guarantee.

Pros of Building Out

• Generally avoids any major structural changes to your existing home.
• Inherently accessible.
• Great for opening up certain areas of your home while leaving the others intact.

Cons of Building Out

• Reduces yard size.
• Extra care must be taken to make addition look like it “fits” with the rest of your home, or is a nicely contrasting pair to it.
• Requires a new foundation, floor, and roof in the area of the addition.

Any remodel or addition is specific to your house. It is one of the reasons why there isn’t a magic solution to universal pre-fabricated housing, or why people just don’t use stock plans. A solution that is customized to your budget and location helps ensure that you make the best decisions when faced with a remodeling decision. In the end, when you need more space, it is more important that you move forward, whether that is up, down, or out.