Renton Highlands

A daylight basement converted into a 1-bedroom AADU with a separate exterior entry and full kitchen.

Size

480 sq ft

Investment

$142k

Build time

4.5 months

Renton Highlands — Basement exterior in Renton, WA

— The Build

How this one came together.

The 480 sq ft daylight basement had 7'9" ceilings — just enough for AADU code. We cut a new exterior door on the south side for separate egress and added two egress-compliant bedroom windows.

Renton permits cleared in 5 weeks. Construction was 4.5 months including a 3-week wait on the egress window-well excavation.

Rents at $1,500/mo to a long-term tenant. Payback projects at 7.9 years.

What's inside

✓Separate south-facing entry
✓Egress-compliant bedroom windows
✓Full kitchen with apartment-size range
✓Sound-isolated ceiling assembly

— Gallery

Site walk-through.

Finished basement ADU — After: full basement ADU

Original unfinished basement — Before: unfinished basement

Renton Highlands home exterior — Exterior with new separate entry

Owner

"Cheapest path to rental income on our lot. The basement was already there — we just made it legal and livable."

P. & L. Singh · Homeowners, Renton

— Questions

About this build.

What's the minimum ceiling height for a basement ADU in Washington?+

Washington's residential code requires 7'0" minimum ceiling height in habitable spaces, with 6'8" allowed under beams and ducts.

West Seattle Sound View

Redmond East