Now covered in more depth
Mercer Island is one of the most architecturally significant residential communities in the Pacific Northwest. Situated entirely on an island in Lake Washington, it offers unmatched waterfront access, proximity to Seattle and Bellevue, and a residential character that ranges from 1950s mid-century estates to contemporary waterfront compounds. Piper Cole Architects brings 25+ years of Seattle-area experience to Mercer Island projects.
Architecture Services on Mercer Island
Waterfront Custom Homes
Maximizing lake views, dock access, and shoreline setback requirements
Estate Renovation
Updating older Mercer Island homes while preserving their character and views
ADU Design
Backyard cottages and attached ADUs under City of Mercer Island codes
Home Additions
Expanding existing homes without compromising the site’s natural assets
Mercer Island Building Codes and Permit Process
Mercer Island projects are permitted through the City of Mercer Island Development Services. Shoreline properties are subject to additional Shoreline Master Program review. Mercer Island has specific tree retention requirements and critical area protections that affect buildable area on many lots. Piper Cole Architects navigates these requirements with experience gained from numerous Island projects.
Planning a project?
Working out what your lot will allow, and what it will cost?
Send David the address and a few lines about what you want. The first feasibility check is free and usually takes about a day: what the site and the code are likely to allow, and what to check first.
Architect since 1996, member of the AIA and NCARB. Three Masonry Excellence Awards for commercial projects; the Carr residence was featured in Above The Lake and Lux magazines.
Mercer Island ADU Rules
Mercer Island allows both attached and detached ADUs consistent with Washington State law. DADUs are permitted in residential zones with standard setback and height requirements. The Island’s premium rental market makes ADUs particularly attractive investments.
