If you’ve ever thought about adding an Accessory Dwelling Unit (ADU) to your property, you’ve probably wondered:

👉 Should I convert my garage, or build something brand new?

On paper, both sound great. But in practice, the difference in cost, time, and lifestyle impact can be huge. Let me walk you through what we’ve learned from real homeowners — including one in Bremerton whose story might sound familiar.

A Homeowner’s Story: When Building Up Didn’t Add Up

Not long ago, a homeowner reached out with a plan: she wanted to build a new ADU above her two-car attached garage. Her backyard was tiny, so going vertical seemed like her only choice.

But here’s the twist — she had just replaced her entire roof two weeks earlier.

A second-story ADU meant tearing off that brand-new roof, framing an entirely new structure, and then reroofing again. The costs were staggering, and the timeline? At least a year and a half between permitting, construction, and inevitable weather delays.

She was frustrated. She wanted a smart investment — not to undo something she had just paid for.

So, we suggested a different path: converting her garage. By moving her storage into a backyard shed, she could transform her garage into a rental-ready ADU in just 2–3 months, at nearly half the cost.

For her, the choice was clear. But what about you? Let’s break it down.

Why Garage Conversions Work So Well

Think about your garage for a moment. How often do you really use it? For cars? Is parking outside a variable option?

That’s why conversions make so much sense — you’re turning wasted space and opportunity into valuable space.

Here’s what makes them appealing:

• Faster Timelines
  You’re not waiting on the weather to pour new foundations, or jumping through hoops for massive structural inspections. A garage conversion can be wrapped up in just a couple of months. Compare that to a new ADU, which often drags out for a year or more.
  
• Lower Cost Without Cutting Corners
  You already have walls, a roof, and a foundation. That means you’re investing in finishes, insulation, plumbing, and design — not paying to build an entire structure from scratch. The savings can be enormous.
  
• Return on Investment
  Conversions often recoup most of their costs because buyers and renters see immediate value in that extra livable space. And since they’re quicker to complete, you can start generating rental income faster.
  
• Practical Lifestyle Upgrade
  Instead of leaving your garage to gather dust, you get a guest suite, a rental unit, a home office, or even a space for aging parents — all without major disruption to your yard or your daily life.
  

But they’re not perfect.

• Your design is limited to the existing footprint. You can’t expand the space without major work.
  
• You’ll need to find a solution for parking and storage (a shed often does the trick).
  
• If your garage is in poor condition, fixing the structure could cut into your savings.
  

Why New ADU Construction Still Has Its Place

Now, let’s flip it around. What if you want more than what your garage can offer?

A brand-new ADU gives you something conversions never can: complete freedom.

Here’s what stands out about new builds:

• Design Without Limits
  With a blank canvas, you can choose the size, the layout, the finishes, and the amenities. Want a two-bedroom unit with a full kitchen and vaulted ceilings? A detached cottage with maximum privacy? New construction lets you build exactly what you envision.
  
• Bigger Living Space
  Garages have boundaries. New ADUs don’t. You can create a true second home on your property, perfect for long-term rentals, family housing, or multigenerational living.
  
• Privacy and Independence
  A detached ADU feels like its own home. Tenants or family members have their own entrance, their own outdoor space, and their own sense of independence — something conversions sometimes can’t match. Want to explore another angle? Read ADU vs. Traditional Home Addition for a full breakdown.
  

But here’s the trade-off:

• Higher Investment
  A new ADU requires land, foundation work, framing, roofing — the whole package. It’s a serious financial commitment.
  
• Longer Timelines
  Between permitting, inspections, design, and weather delays, new builds can easily stretch into 12–18 months.
  
• Weather & Zoning Delays
  In rainy climates like the Pacific Northwest, foundation work often gets delayed until spring. Add in stricter zoning and parking requirements, and you’re in for a long journey before move-in day.
  

The Real Question: What’s Right for You?

So, which is better? It depends on your priorities:

• If you want speed, affordability, and practicality, garage conversions often win. You get the benefits of an ADU without waiting years or draining your budget.
  
• If you want long-term luxury, maximum privacy, and a design tailored to your vision, a new ADU build is worth considering.
  

For the Bremerton homeowner, the decision was simple once she saw the big picture. Tearing up a brand-new roof and waiting a year and a half didn’t make sense. A garage conversion gave her what she needed in months, at half the price.

Final Thought

The choice between a garage conversion and new ADU construction isn’t just about walls and windows. It’s about what works best for your life right now — your budget, your timeline, and your long-term goals.

Sometimes the smartest investment isn’t building something new, but reimagining what you already have. Want to dive deeper? Check out our post: Why Build an ADU in Seattle? (And What We Learned Doing It Ourselves) for more insights and first-hand lessons.