DOS Designers
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DOS Designers, which stands for Designers Of Spaces, operates out of Bend, Oregon with a secondary focus on the Portland metropolitan area. The firm was founded in 2017 by Kadi Driver and Seth Ehlinger, two architects with deep experience in residential design and Oregon building practices. Their approach to ADU design emphasizes site feasibility, financial projections, and coordinated support through the local permitting process, positioning ADU work as a specialized service line rather than a generic addon.
Kadi Driver brings expertise in interior and architectural design, with a track record in sustainable, minimalist principles and historic preservation. Seth Ehlinger holds a University of Oregon architecture degree and spent years in design-build contracting and construction management before becoming a full architect. That construction background is notable; architects who have managed actual building projects understand the constraints contractors face and design accordingly. Seth's ability to translate a client's wish list into a coherent vision that exceeds expectations, as the firm describes it, reflects years of translating abstract ideas into buildable reality.
The firm is certified through AIBD (American Institute of Building Design), a professional standard that signals competence in residential design and code understanding. That certification matters for permitting purposes; building departments often flag uncertified design more carefully than work from credentialed professionals. Having a certified designer on staff gives the drawings a presumption of competence when they land on an inspector's desk.
DOS Designers serves Clackamas, Washington, and Multnomah Counties, which spans the Portland metro area from Hillsboro in the west to Milwaukie in the south and Troutdale in the east. That geographic scope covers a diverse set of permitting jurisdictions, each with subtly different code interpretations and local requirements. Having worked across that range, DOS understands which cities are code-strict and which prioritize efficiency, which inspectors ask for additional structural detail and which focus on other elements. That accumulated knowledge shapes the design process; the firm steers you away from concepts that will face pushback and toward approaches that move quickly through review.
The ADU design service begins with a comprehensive feasibility study. DOS visits the property and evaluates lot size, topography, existing structures, zoning, setback rules, driveway and parking constraints, utility routing, and any environmental factors that might affect building. From that assessment, the firm provides preliminary drawings showing one to three design options for how an ADU could fit on your property. The feasibility study also includes rough construction cost estimates tailored to Portland market rates and rental income projections based on local ADU comparable sales. That combination of design options plus financial modeling helps homeowners decide whether an ADU makes sense for their situation before investing in full permit drawings.
ADU designs from DOS typically fall in the 300 to 800 square foot range, covering studios through two-bedroom configurations. The firm guides you through the trade-offs: a studio costs less to build but attracts fewer renters; a two-bedroom generates more rental income but requires more site area and costs more upfront. DOS provides the information you need to make that decision rather than pushing you toward whichever size yields the biggest project fee.
Once you have decided to move forward and settled on a configuration, DOS produces full permit drawings: architectural plans with every dimension and detail, structural framing coordinated by a licensed structural engineer, mechanical and electrical layouts matching your HVAC and power needs, and site plans showing how the building sits on the lot relative to property lines and existing structures. The firm coordinates pre-application meetings with Portland's Bureau of Development Services on your behalf, floating the concept before investing in final drawings. That conversation often catches zoning or code issues early, preventing surprises when you submit for formal review.
The permitting support extends through the city's review process. If BDS comments on the initial submission, DOS addresses the feedback, modifies drawings as needed, and resubmits. The goal is to move through review as efficiently as possible. Permitting timelines in the Portland metro vary by city and complexity; straightforward projects on typical lots might move in weeks, while complicated sites or unusual configurations can take months. DOS manages expectations and keeps you informed on status.
The firm does not offer construction services. Your relationship with DOS ends once permits are approved and you have a full set of drawings to hand to your contractor. You select the builder, manage the construction timeline, and oversee quality. That separation is clean and keeps the architect focused on design and permitting rather than construction liability. It also gives you the freedom to get competitive bids from multiple builders without being locked into the firm's preferred contractor.
Working with DOS makes the most sense if you have a property in the Portland metro area and value having a local architect who knows your city's permitting process and can guide you through feasibility analysis before committing to design. The firm's willingness to spend time upfront on financial modeling and zoning research helps you avoid pursuing ADUs that do not make sense for your property or household. For homeowners uncertain whether an ADU is viable on their lot, that preliminary analysis is valuable even if you ultimately decide not to proceed.
The twenty-plus years of combined experience shows in the details. DOS knows Oregon building code thoroughly and understands how different building types (detached ADUs, attached units, converted existing structures) face different scrutiny in permitting. That expertise lets the firm anticipate city concerns and design accordingly. The design thinking is also grounded in actual construction experience; Seth Ehlinger's years in design-build mean the firm avoids beautiful designs that are difficult or expensive to build, which is a common failure mode in ADU architecture.
Pricing is custom quoted based on project scope and complexity. The firm does not publish standard rates, so you need to reach out for an estimate. Typical ADU projects in the Portland area run somewhere in the mid-range between template-based plans and fully bespoke custom design. The exact cost depends on site complexity, your needs, and how much coordination with the city is required.
DOS Designers is a strong fit for Portland-area homeowners who want design expertise grounded in local knowledge and are willing to invest in thorough feasibility analysis before committing to construction. The co-founders' combined experience and AIBD certification signal real competence. The firm's emphasis on understanding site constraints, financial realities, and permitting pathways upfront reflects a thoughtful approach to ADU design. For homeowners ready to move forward with confidence, DOS provides the expertise and local credibility to get there.