- (253) 338-1693
- [email protected]
- Mon - Fri: 9:00 - 18:00
Cascade Pro Inc builds accessory dwelling units and garage conversions across Tacoma, Seattle, and the greater Puget Sound region. Whether you want to convert an existing garage into a rental unit, build a detached ADU in your backyard, or transform your basement into an independent living space, we handle every step — from initial design and city permits through final construction and inspection.
As a licensed general contractor with over 15 years of experience in residential construction, we understand the local building codes, zoning requirements, and permit processes in Pierce County and King County. Our team works directly with city planning departments in Tacoma, Seattle, Puyallup, Federal Way, Lakewood, Auburn, and Kent to make sure your project is approved and built to code.
Every property is different, and the right ADU solution depends on your lot, your goals, and your budget. We specialize in three main types of accessory dwelling units:
A garage conversion is one of the most cost-effective ways to add living space to your property. We convert attached and detached garages into fully finished living areas complete with insulation, electrical, plumbing, HVAC, and all required egress. Many homeowners in Tacoma and Seattle use garage conversions to create rental income, house aging parents, or provide a private space for adult children. Because the structure already exists, a garage conversion typically costs less and takes less time than a ground-up build.
A detached ADU is a standalone structure built on your existing lot — sometimes called a backyard cottage or mother-in-law suite. We build custom detached ADUs from the foundation up, including site preparation, utility connections, and landscaping restoration. In Washington State, recent legislation has made it easier than ever for homeowners in single-family zones to add a detached ADU. We help you navigate these new rules and maximize the allowable square footage on your property.
If your home has an unfinished or underused basement, converting it into an ADU can add significant value to your property without changing your home’s footprint. Basement ADU conversions require careful attention to egress windows, ceiling height requirements, waterproofing, and separate utility metering. Our team has completed basement conversions across Pierce County and King County, and we know exactly what local inspectors look for during the approval process.
One of the biggest challenges homeowners face with ADU projects is coordinating between designers, permit consultants, and contractors. At Cascade Pro Inc, we handle everything under one roof:
Design & Planning — We work with you to create a layout that fits your property and your goals. Whether you want a studio apartment, a one-bedroom unit, or a two-bedroom family space, we design for both livability and code compliance. We also offer pre-approved floorplans for homeowners who want a faster, more streamlined process.
Permits & Approvals — Permitting is where many ADU projects stall. We prepare and submit all required documents to the city, coordinate with planning departments, and handle any revision requests. We are familiar with the specific permit requirements in Tacoma, Seattle, and surrounding jurisdictions including Puyallup, Federal Way, Lakewood, and unincorporated Pierce County.
Construction & Inspection — Once permits are approved, our crew handles demolition (if needed), framing, electrical, plumbing, HVAC, drywall, flooring, and finish work. We coordinate all required inspections and deliver a move-in ready unit that meets all local and state building codes.
The demand for ADUs in the Puget Sound area has grown rapidly over the past several years. Homeowners are building accessory dwelling units to generate rental income in a strong market, provide independent housing for family members, increase their property value, and make better use of existing space on their lot. Washington State has passed legislation making ADU construction easier, and cities like Tacoma and Seattle have updated their zoning codes to encourage ADU development in residential neighborhoods.
Whether your motivation is financial, personal, or both, an ADU is one of the highest-return investments you can make in your property. A well-built ADU can generate steady monthly rental income in the Tacoma and Seattle rental markets, and the income potential continues to grow as housing demand in the region increases. If you need more living space but aren’t sure an ADU is right for your property, a room addition may be another option worth exploring.
ADU costs vary widely depending on the type of project, the size of the unit, the condition of the existing structure (for conversions), and the finishes you choose. Every project is different, and the best way to get an accurate number is with a free consultation and detailed estimate.
Garage conversions are generally the most affordable ADU option because you’re working with an existing structure. The final cost depends on the size of the garage, the extent of structural modifications needed, and the level of finish—from a basic studio conversion to a full one-bedroom unit with a kitchen and bathroom.
Detached new-build ADUs involve ground-up construction including foundation, framing, roofing, full MEP systems, and interior finishes. These projects cost more than conversions, but offer complete design flexibility. The final price depends on the unit size, site conditions, and your chosen finishes.
Basement ADU conversions can be a cost-effective option if you already have a full or partial basement. Costs depend on whether the space is already finished, if you need to add egress windows, and the scope of the plumbing and electrical work required.
We provide free, no-obligation estimates for every project so you know exactly what to expect before work begins. Give us a call at (253) 338-1693 to discuss your ADU project.
We keep the process straightforward so you always know what to expect:
1. Free Consultation — We visit your property, discuss your goals, review your lot for feasibility, and provide a preliminary scope and budget estimate. There is no cost and no obligation.
2. Design & Engineering — Once you decide to move forward, we create detailed plans including structural engineering, electrical layouts, and plumbing schematics. All designs comply with current Washington State residential building codes.
3. Permitting — We submit plans to the city, manage the review process, and address any comments from plan reviewers. Permit timelines vary by jurisdiction — Tacoma typically processes ADU permits in 4 to 8 weeks, while Seattle may take longer depending on the scope of the project.
4. Construction — We build your ADU with our own crew, not subcontracted labor. You get a dedicated project manager, regular progress updates, and a clean job site. Most ADU projects take 3 to 6 months from permit approval to completion.
5. Final Inspection & Handoff — We schedule all required final inspections, address any corrections, and hand you the keys to a finished, code-compliant unit ready for occupancy or rental.
Cascade Pro Inc provides ADU and garage conversion services throughout the greater Tacoma and Seattle metro area. We regularly work in Tacoma, Seattle, West Seattle, Puyallup, Federal Way, Lakewood, Auburn, Kent, University Place, Bonney Lake, and surrounding communities in Pierce County and King County. If your property is within roughly an hour of Tacoma, we can likely serve you.
Ready to explore adding an ADU or converting your garage? Contact Cascade Pro Inc for a free, no-obligation consultation. Call us at (253) 338-1693 or fill out the form above to get started. We will visit your property, evaluate your options, and provide a clear estimate so you can make an informed decision.
Tell us about your ADU or garage conversion project. We offer free consultations and transparent pricing for homeowners across Tacoma, Seattle, and the Puget Sound area.
We proudly serve homeowners throughout the Tacoma and South Puget Sound region. Click on your city below to learn more about our services in your area.
