Tacoma's Trusted ADU Contractor — Custom Builds from Permits to Move-In

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Tacoma's Trusted ADU Contractor — Custom Builds from Permits to Move-In

Add living space, rental income, or a home for family — right on your Tacoma property. Cascade Pro, Inc designs and builds accessory dwelling units throughout Tacoma and Pierce County, handling everything from initial design and city permits to final inspection.

Whether you’re planning a detached backyard cottage, converting an existing garage, or adding a basement apartment, our team manages the full process so you don’t have to.

Types of ADUs We Build in Tacoma

Tacoma allows several types of accessory dwelling units depending on your property and zoning. Cascade Pro builds all of them:

Detached ADUs (Backyard Cottages)

A standalone structure built on your property, separate from the main house. Detached ADUs are the most popular option, offering maximum privacy for both the homeowner and the occupant. They work best on lots with adequate backyard space and proper setbacks.

Attached ADUs

An addition built onto your existing home with its own separate entrance. This is a strong option when backyard space is limited or when you want the unit connected to the main house for accessibility or family use.

Garage Conversions

Convert your existing detached or attached garage into a fully permitted living space. Garage conversions are often the most cost-effective ADU option because the structure is already in place. We handle structural upgrades, insulation, plumbing, electrical, and finishes to bring it up to residential code.

Basement ADUs

If your home has an unfinished or partially finished basement, converting it into a legal ADU can add significant value with a lower construction footprint. We ensure proper egress windows, ceiling height compliance, moisture control, and separate entry as required by building code.

Completed ADU garage conversion with modern siding and landscaping by Cascade Pro in Puget Sound
Finished basement ADU conversion with modern living space

How We Build Your ADU — Step by Step

Every accessory dwelling unit project follows a structured process to keep timelines tight and surprises to a minimum:

  1. Consultation & Site Assessment — We visit your Tacoma property to evaluate lot size, access, utility connections, soil conditions, and zoning. We’ll discuss your goals — rental income, multi-generational living, home office, or long-term property value.
  2. Design & Engineering — Our design team creates a custom floor plan that maximizes your available space while meeting local building code. We coordinate with structural engineers and prepare all documents needed for permit submission.
  3. Permits & Approvals — We submit plans directly to the City of Tacoma and manage the review process through all stages. Permitting timelines can vary, and we stay on top of every step so you don’t have to.
  4. Construction — Once permits are approved, our crew breaks ground. We handle site prep, foundation, framing, electrical, plumbing, HVAC, insulation, drywall, and finishes. You’ll have a single point of contact throughout the build.
  5. Final Inspection & Handoff — We coordinate all required inspections, address any punch-list items, and hand you the keys to a fully finished, code-compliant ADU.

Why Tacoma Homeowners Choose Cascade Pro for ADU Construction

Building an ADU in Tacoma is one of the smartest investments a homeowner can make — but only when it’s done right. Tacoma’s building codes have become increasingly ADU-friendly, and the city’s strong rental market makes property improvements a smart investment. As your local general contractor based right here in Tacoma, we know the permitting process inside and out.

  • Licensed, bonded, and insured general contractor serving Tacoma and Pierce County
  • Thorough knowledge of local ADU zoning requirements, including lot coverage, setback, and height regulations
  • Full-service builds — we handle architectural design, engineering, permits, construction, and final inspection
  • Transparent communication with a dedicated project manager on every job
  • Proven experience building ADUs across Tacoma neighborhoods

What Does It Cost to Build an ADU in Tacoma?

ADU costs in Tacoma vary based on the type of unit, size, site conditions, finishes, and whether you’re building new construction or converting existing space. Garage and basement conversions typically come in at a lower price point than ground-up detached units because they leverage an existing structure.

Key factors that influence your project budget:

  • Unit type — detached new builds require more foundation, framing, and roofing work than conversions
  • Size and layout — a studio ADU costs less than a full one- or two-bedroom unit
  • Site conditions — slope, soil, utility access, and distance from the main house all affect prep costs
  • Finish level — standard finishes vs. upgraded countertops, fixtures, and flooring
  • Permit and design fees — vary based on project scope and local fee schedules

We provide detailed, transparent estimates after our initial site assessment so you know what to expect before any work begins. Every project is different — we’ll walk you through the numbers and help you make informed decisions that fit your budget.

Exterior view of detached ADU with covered entry built by Cascade Pro in the Tacoma area

Tacoma ADU FAQs

Most residential lots in Tacoma are eligible for at least one ADU, though requirements vary by zoning, lot size, and access. During our consultation, we’ll verify your lot’s eligibility and walk you through what’s possible on your specific property.

Timelines vary by project type. A typical detached ADU takes roughly 6 to 10 months from design through completion, including the permitting phase. Garage and basement conversions can often be completed faster since the existing structure reduces construction time. We’ll give you a realistic timeline during our initial assessment.

Owner-occupancy requirements vary by jurisdiction. Many areas have relaxed or removed this requirement in recent years. We’ll clarify the current rules for your specific property during our consultation.

In most cases, yes. A well-built, permitted ADU adds usable square footage and income potential to your property. The actual value increase depends on the unit type, size, finishes, and location within Tacoma.

Yes. We manage the entire permitting process, including plan submission, revisions, and coordination with inspectors. You don’t have to navigate the building department on your own.

Short-term rental regulations vary by city and are subject to change. We build every ADU to full residential code, which keeps your options open regardless of how you choose to use the space. We recommend checking current local regulations before planning a short-term rental use.

Ready to Build Your Tacoma ADU?

Whether you’re planning a backyard cottage, converting a garage, finishing a basement, or adding on to your home — Cascade Pro, Inc is ready to make it happen. We’ve helped homeowners throughout Tacoma navigate the ADU process from first sketch to final walkthrough, and we’d love to do the same for you.

Call us today: (253) 338-1693 or fill out the form to schedule your free consultation.

Ready to Get Started?

Tell us about your accessory dwelling unit project. We offer free consultations for Tacoma homeowners.

About Us
Cascade Pro Inc general contractor team Tacoma Seattle

Serving Tacoma Neighborhoods from Stadium District to South End

As Pierce County's largest city, Tacoma offers a diverse housing landscape that spans historic Craftsman homes in the Stadium District and North End to mid-century ramblers in South Tacoma and newer developments along the waterfront in Ruston. Each neighborhood comes with its own zoning requirements and architectural character that we understand inside and out.

Tacoma's ongoing revitalization — from the Hilltop Link Extension to the Dome District redevelopment — has made home improvement one of the smartest investments in the region. Whether your property sits near Point Defiance Park, along 6th Avenue, or in the Eastside, our team knows the local permitting process through Tacoma's Planning and Development Services and works within the city's specific ADU, remodeling, and building codes to keep your project on track.

We've completed projects across Tacoma's most popular neighborhoods including Proctor, Old Town, Lincoln, McKinley Hill, and the Narrows. Our familiarity with local soil conditions, setback requirements, and historic district guidelines means fewer surprises and a smoother build from start to finish.

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