ADU Construction in Bellevue

Somerset lots run 9,000–12,000 sq ft. That's real room for a detached ADU under WA HB 1337 — the 2024 state law letting most Bellevue single-family parcels add two units by right, no variance required. Vladislav Volkov has pulled ADU permits through Bellevue's own permit center on 116th Ave NE. Since 2017, 100+ projects completed across Seattle Metro. Clients in 98006 and 98004 regularly spec the ADU kitchen around a Wolf range or Bosch appliance package — those finish choices affect structural layout, so they're on the table from the first design conversation. Panel-ready Sub-Zero refrigerators require deeper cabinet bays and specific rough-in locations that can't be repositioned after framing. Better to resolve that in the design phase than during the punch list.

Bellevue's mid-century ranchers and split-levels — built primarily between 1960 and 1975 in Newport Hills, Factoria, and the Crossroads corridor around zip code 98007 — sit on lots platted long before ADUs existed in the code. Detached garages here are common and often convert cleanly into DADUs without touching the main structure. That older construction brings real surprises during rough-in inspection. Galvanized water lines and aluminum wiring from the 1965–1973 era appear more often than homeowners expect, especially near Mercer Slough where crawlspaces stay damp through April. A vapor barrier upgrade frequently gets added to scope once the crawlspace opens up — it's not optional when there's standing moisture evidence on the pier blocks. Plan the budget accordingly. Somerset and Bridle Trails are a different story. Bigger lots, cleaner utility runs, newer structures with fewer hidden conditions. Setback math and lot coverage calculations still happen on-site, not from a satellite image.