Accessory Dwelling Unit Builder in Pierce County

Building an accessory dwelling unit is one of the most practical ways to add flexibility, function, and long-term value to your property. Thatcher Construction helps homeowners move from early questions to a finished ADU with a design-build process grounded in planning, communication, and quality work.

Whether you are planning a rental unit, a private space for family, or a long-term addition to your property, the process works best when you have a contractor who understands both construction and the homeowner's perspective. That is the approach Thatcher brings to ADU projects across Pierce County.

What an ADU Can Do for Your Property

An accessory dwelling unit, or ADU, is a secondary living space built on the same lot as your primary home. It can be attached to the main house, detached elsewhere on the property, or converted from an existing structure such as a garage. In Washington, detached accessory dwelling units are often called DADUs.

ADUs can serve several practical goals:

  • A rental unit that creates ongoing income potential
  • Private living space for an aging parent, adult child, or extended family member
  • A separate home office, studio, or guest space
  • Long-term flexibility as your household changes over time

The right ADU depends on your lot, the structures already on the property, how you plan to use the space, and the local rules that apply in your jurisdiction. A builder who has worked through those variables before can help you make better decisions before design starts.

Why an Engineering-Informed Design-Build Approach Matters

Thatcher Construction was founded by Drew Thatcher, a former U.S. Navy nuclear engineer, and project management is led by Jack Hance, who brings a mechanical engineering background and prior commercial construction experience. That engineering mindset shapes how the company plans and executes residential projects.

What that means for homeowners:

  • Design decisions are made with structural and practical trade-offs in mind, not aesthetics alone
  • Scope is defined carefully before construction begins, which helps reduce surprises later
  • The build process is managed with discipline, coordination, and clear communication

Homeowners who have worked with Thatcher consistently emphasize professionalism, reliability, and respect for their home. Those qualities matter on an ADU project, where the work is significant and the process touches everything from planning to final walkthrough.

Why Homeowners Across Pierce County Are Considering ADUs

Homeowners in Lakewood, Tacoma, University Place, Steilacoom, Puyallup, and surrounding Pierce County communities are looking for more flexible ways to use their property. Rising housing costs, multigenerational living needs, rental potential, and the need for dedicated work or guest space have all made ADUs more relevant than they were a few years ago.

Washington State has made it easier for homeowners to explore ADUs in recent years, but local review still matters. Requirements related to setbacks, height, size, occupancy, and permitting can vary by city and jurisdiction. That is why the early planning conversation matters so much. If you want to better understand how local review typically fits into the process, see our ADU permitting page.

Why build an ADU?

With rising home prices and increased demand for flexible housing, Accessory Dwelling Units ADUs offer homeowners an incredible opportunity to create value and meet evolving lifestyle needs. Common reasons Lakewood homeowners build ADUs include:

Housing for Aging Parents

Give loved ones independence with close proximity and accessibility.

Rental Income

Turn unused space into a long-term or short-term rental to offset your mortgage.

Adult Children or Other Family

Provide privacy and self-sufficiency while staying under one roof.

Work From Home Studio or Office

Create a peaceful, dedicated space for productivity without commuting.

Guest Suite

Welcome visitors without giving up personal space in the main home.

The Thatcher Design-Build Process

Thatcher Construction operates as a design-build contractor, which means design and construction are handled through one coordinated process. For ADU projects, that matters because design choices affect permitting, buildability, budget direction, and the overall homeowner experience.
Here is how the process typically works:

1

Consultation

We start with your goals, your property, and the role the ADU is meant to play. That could mean a rental unit, family housing, guest space, or something more flexible. This early conversation helps define the right path.

2

Design & Planning

We work through layout, structural needs, function, and finish direction with your priorities in mind. Strong planning up front reduces friction later.

3

Permitting Coordination

Your project will move through the local permit process. We help you understand what is typically required and what steps usually shape the review process, while keeping expectations realistic.

4

Construction

The build moves forward with active project management, clear communication, and attention to site condition and workmanship. Homeowners consistently value crews who show up when expected, keep the site clean, and stay professional throughout the project.

5

Final Inspection & Handoff

We complete the project with a final walkthrough and ensure every detail meets your expectations.

6

Completion

The project is not done until the space is complete, final items are addressed, and the ADU is ready for use.

For a more detailed breakdown of how this works, visit our ADU design-build process overview.

Detached ADUs, Attached ADUs, and Garage Conversions

ADUs can take several forms, and the right option depends on your lot, your goals, and the kind of space you want to create.

A detached ADU, sometimes called a DADU, is a freestanding structure built separately from the main home. It often works well when privacy and separation matter most.

An attached ADU shares a wall with the primary house. This can make sense when a fully detached structure is not the best fit for the property or when closer proximity is actually helpful.

A garage conversion reuses an existing structure rather than starting from the ground up. In some cases that can simplify the project, but it also brings its own structural, layout, and approval questions.

Sorting through these options is one of the first strategic decisions in the process. If you want to look deeper at the trade-offs, see our pages on detached vs. attached ADUs and garage conversion vs. new ADU construction.

We provide a detailed estimate after the consultation and work with you to prioritize your must-haves while staying within budget.

How to Think About ADU Cost Without Guessing

ADU cost depends on project type, size, site conditions, complexity, utility needs, and finish level. A detached build on a straightforward lot is a different project from a garage conversion with structural limitations or a highly customized attached suite.

We do not publish broad price ranges on this page because numbers without context can be more misleading than helpful. What matters more at this stage is understanding what drives cost and making early design decisions that reduce expensive course corrections later.

If budget is one of your biggest questions, our ADU cost guide is the best next step. If you are still deciding how the space should function, our page on the best uses for an ADU can help you think through the options.

Areas We Serve for ADU Projects

Thatcher Construction builds ADUs and DADUs for homeowners in Lakewood and across Pierce County. Core service areas include:

If your property is in a nearby Pierce County community, reach out. We are happy to talk through whether your project is a fit.

Frequently Asked Questions

What are the rules for ADUs in Washington State?

Washington State has made major changes in recent years to support more ADU development, but local jurisdictions still control many of the details. Setbacks, height limits, maximum size, occupancy rules, and permit expectations can vary depending on the city. What applies in one Pierce County community may not apply exactly the same way in another. The best approach is to review your property and project goals in the context of your local jurisdiction.

Are ADUs allowed in Washington?

Yes. Washington State broadly allows accessory dwelling units, but every project still needs to move through the applicable local review and permitting process. That means the details matter, even when the overall direction of state law is ADU-friendly.

What are the most common mistakes when building an ADU?

The most common mistakes usually happen early. Homeowners may underestimate the complexity of site conditions, move too quickly into design without understanding local constraints, or choose a contractor who does not have a strong process for coordinating design, review, and construction. A clear plan up front helps reduce the problems that create budget pressure and project delays later.

What is the most cost-effective way to build an ADU?

The most cost-effective path is usually the one that aligns the design with the property and the intended use from the beginning. Simpler layouts, efficient space planning, and realistic scope decisions tend to control cost better than trying to force a concept that does not fit the lot or project goals. In some cases, a garage conversion may be cost-effective, but that depends on the structure and the trade-offs involved.

Why does building an ADU cost as much as it does?

An ADU is still a complete dwelling unit. That means structure, foundation work, electrical, plumbing, HVAC, insulation, interior finishes, and site coordination all have to come together in a smaller footprint where efficiency matters. Utility connections, review requirements, and construction complexity all influence the total cost.

Is an ADU a smart investment?

For many homeowners, yes. An ADU can create rental potential, support multigenerational living, add flexibility to the property, and improve long-term usefulness. Whether it is the right investment for your situation depends on your goals, your property, and how you plan to use the space.

What is the ROI on an ADU?

There is no single ROI number that applies to every ADU. Value depends on location, build quality, intended use, financing, and the local market. Rental income may matter most for one homeowner, while housing flexibility for family matters more for another. A well-planned ADU typically creates more durable value than a rushed project built without a clear strategy.

What is the best financing option for building an ADU?

Many homeowners look at home equity loans, HELOCs, or construction financing when planning an ADU. Financing options change over time, and the best path depends on your property, your equity position, and your goals. A lender or financial advisor is the best source for current financing guidance. Our role is to help you define the project clearly enough that you can have those conversations with more confidence.

Start with a Practical Conversation

If you are considering an ADU, the next step does not have to be a final commitment. It can simply be a practical conversation about your property, your goals, and the kind of ADU that may make sense.

Thatcher Construction works with homeowners across Pierce County who want a thoughtful, well-managed path from concept to completed space. If you are still in research mode, we can help you think through the major decisions. If you are ready to talk about your project, we can help you take the next step.

Visit our contact page or submit your info below to request a free estimate/consultation and start the conversation.

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