Home Addition Architect in Redmond, WA

I’ve worked with dozens of Redmond homeowners who have hit the same wall: the house they bought five or ten years ago no longer fits their life. A new baby, a parent moving in, a remote job that demands a real office — the reasons vary, but the conclusion is the same. Moving makes no sense when Eastside prices are what they are and when your neighborhood, your schools, and your commute are already dialed in. A well-designed home addition is almost always the smarter path.

My name is David Meade. I’m a licensed architect with AIA and NCARB credentials, and I’ve been designing home additions and whole-home expansions across the Eastside for more than 25 years. Redmond is one of our core service areas — we know its neighborhoods, its zoning codes, and its permit counter. If you’re considering a home addition in Redmond, here’s what you need to know.

Types of Additions We Design in Redmond

Redmond’s housing stock is diverse. You’ll find post-war ramblers on Education Hill sitting next to 1990s colonials in Grass Lawn, newer craftsman-style homes in Willows, and townhomes near Downtown Redmond and Overlake. Each property type calls for a different addition strategy.

Second-story additions are among the most popular projects we handle in Redmond. When a lot is nearly built out at grade — common in the Overlake and Bear Creek neighborhoods where original houses were designed to cover a generous footprint — going up is the only viable direction. A second story can add 800 to 1,500 square feet and transforms a ranch-style home into a full two-story residence. This is also our most structurally complex addition type: we work with a licensed structural engineer on every second-story project.

Room additions — a primary suite, a home office wing, a guest bedroom, or a playroom — are the bread and butter of residential addition work. Redmond’s tech-worker households frequently request dedicated home offices, and we’ve designed spaces specifically engineered for acoustics, video conferencing light levels, and ergonomic layouts. Many clients in the Grass Lawn and Education Hill areas add a main-floor primary suite so they can age in place.

Garage conversions and ADUs have become one of the most requested project types since Washington State expanded ADU-friendly zoning under HB 1337. Redmond is a Tier A city under HB 1110 with roughly 70,000 residents within the Urban Growth Area, which means local code has been updated to accommodate more ADU and multi-unit density. We design garage conversions into accessory dwelling units for multigenerational households — adult children, aging parents, or long-term guests — as well as detached ADUs on appropriate lots.

Sunrooms and covered additions extend living space without the full cost of a conditioned room addition. We design both unconditioned sunrooms and fully insulated, year-round family rooms depending on client goals and budget.

Master suite expansions round out the most common requests. Many 1980s and 1990s Redmond homes have undersized primary bathrooms. We regularly expand into an adjacent bedroom or out over a garage to create the spa-style bathroom and walk-in closet our clients want.

The Architect’s Role in a Redmond Addition

A general contractor can build a home addition. An architect designs one that works — spatially, structurally, and in terms of code compliance.

Here’s what that means in practice. Before a single permit drawing is produced, I spend time analyzing how the new square footage will relate to your existing home. Traffic flow, natural light, ceiling heights, structural load paths — all of these have to be resolved in the design phase, not discovered during framing. Schematic design is where we explore options: do you add square footage to the back of the house or above the garage? Does the new primary suite connect directly to the existing hallway or does it warrant a dedicated wing?

Beyond design, an architect on your project means permit-ready construction documents. Redmond Development Services requires stamped architectural drawings for most permitted additions. We produce full drawing sets — site plans, floor plans, elevations, sections, and details — coordinated with structural engineering when needed. We also handle communication with the city during plan review, which speeds up the process considerably.

Finally, I provide independent oversight during construction. I’m not a contractor; I work for you. That means I’m reviewing work against the approved drawings and flagging issues before they become expensive problems.

For a full look at how this fits into our broader practice, see our renovation and restoration services.

Redmond’s Permit Process for Additions

Plan for 6 to 10 weeks for standard residential addition permits through City of Redmond Development Services. That timeline assumes a clean application with no critical area complications and no requests for administrative variances.

What triggers a longer review? The most common complication in Redmond is critical area proximity. The city has significant wetland and stream buffers — the Sammamish River corridor, Bear Creek, and Evans Creek all run through residential areas. If your addition footprint comes within a required buffer, you’ll need a Critical Areas Review, which can add 4 to 8 weeks and may require a SEPA (State Environmental Policy Act) checklist. I always pull the city’s critical areas overlay before design begins so we’re never surprised.

Lot coverage and setbacks govern how much you can add at grade. Redmond residential zones (R-1 through R-4) typically limit lot coverage to 35–40% of the gross lot area. Front setbacks are generally 20 feet, rear setbacks 20 feet, and side setbacks a minimum of 5 feet. These numbers vary by zone and can sometimes be modified through a variance process, but it’s faster and cheaper to design within them from the start.

Second-story additions may trigger additional review. A substantial vertical addition can require a full architectural review and, in some cases, a Design Review Board process depending on neighborhood overlay.

We handle all permit submissions, respond to city comments, and track application status on your behalf.

What Does a Home Addition Cost in Redmond?

Honest answer: home addition costs in Redmond in 2026 run $400 to $700 per square foot for the addition itself, inclusive of design, permits, and construction. That’s a wide range, and the spread is real — here’s what drives it.

Construction type is the biggest variable. A ground-floor room addition on a simple foundation with straightforward framing lands at the lower end of the range. A second-story addition requires a structural engineer to evaluate the existing foundation and framing, add steel or engineered lumber as needed, and carry the new load safely — that complexity pushes cost toward the higher end of the range or above it for older homes with marginal existing structure.

Finish level matters considerably. A home office addition with standard finishes costs far less per square foot than a primary suite addition with custom tile, radiant floor heat, and a steam shower.

Site conditions — including critical area proximity, slope, and access for construction equipment — can add meaningful cost.

Architect fees for home addition projects typically run 8–12% of construction cost. For a realistic picture of how architectural fees are structured, see our breakdown of how much an architect costs in Seattle. For broader context on construction pricing across the region, our cost to build a house in Seattle 2026 guide is a useful reference.

As a rule of thumb: budget the full $400–$700 range and let the design process refine the number. We provide detailed cost estimates at the end of schematic design so you can make informed decisions before money is committed to construction documents or permits.

Why Redmond Homeowners Choose Piper Cole

We are not a large firm that takes on addition projects when the custom-home pipeline slows. Home additions and remodels are a core part of our practice. Redmond and the broader Eastside — Kirkland, Bellevue, Sammamish, Issaquah — represent the geographic heart of our work.

Local knowledge. We know Redmond’s zoning overlays, its permit office, and its critical area mapping. We’ve navigated the city’s plan review process many times and know what reviewers flag and what sails through.

Credentials. I hold AIA (American Institute of Architects) membership and NCARB (National Council of Architectural Registration Boards) certification. Both matter for the quality of drawings your permit application requires and for your protection as a client.

25+ years of Eastside experience. Longevity in this market means we’ve seen construction costs cycle, zoning codes change, and design trends come and go. That experience translates into practical advice for your project — not just beautiful drawings.

Full-service delivery. We handle everything from initial site analysis and schematic design through permit submission, contractor coordination, and construction administration. You have one point of contact from concept to certificate of occupancy.

Visit our Redmond architect location page to learn more about our work in the city, or contact us for a free consultation to talk through your specific project.

Frequently Asked Questions

Do I need an architect for a home addition in Redmond, WA?

Washington State law requires a licensed architect’s stamp on construction documents for residential projects that exceed certain thresholds — generally anything that involves structural changes, additions over a certain square footage, or projects in jurisdictions that require stamped drawings for permit. Redmond Development Services requires stamped architectural drawings for most permitted home additions. Beyond the legal requirement, an architect ensures your addition is designed correctly the first time: code-compliant, structurally sound, and integrated with your existing home in a way that adds real value.

How much does a home addition cost in Redmond?

In 2026, plan on $400–$700 per square foot for a home addition in Redmond, inclusive of design, permits, and construction. Ground-floor room additions with standard finishes tend toward the lower end of the range. Second-story additions — which require structural engineering and more complex construction — typically land at the higher end or above it. Finish level, site conditions, and addition type all influence final cost. We provide detailed cost estimates after schematic design so you know the numbers before you commit to full construction documents.

How long does it take to get a permit for an addition in Redmond?

Standard residential addition permits through City of Redmond Development Services typically take 6–10 weeks from a complete application submission. Projects near critical areas (wetlands, streams, or the Sammamish River corridor) may require an additional Critical Areas Review and possibly a SEPA checklist, which can extend the timeline by 4–8 weeks. Incomplete applications — missing structural calculations, unclear site plans, or unresolved zoning questions — are the most common cause of delays. We prepare complete permit packages and respond promptly to plan review comments to keep your project on schedule.

What types of home additions does Piper Cole design in Redmond?

We design the full range of residential additions for Redmond homeowners: second-story additions, ground-floor room additions (home offices, guest suites, primary suites, playrooms), garage conversions to ADUs, detached ADUs, sunrooms, and whole-home expansions. We also design kitchen and bathroom expansions tied to addition projects. Our work spans neighborhoods across Redmond including Education Hill, Grass Lawn, Willows, Downtown Redmond, Overlake, and Bear Creek.