Basement ADU
A lower level turned into a legal unit with its own entry.
Good at
- No new foundation, no yard lost
- Stays cool in summer, easy to heat
- Works well for a grown kid or a long-term tenant
What we check first
- Ceiling height and egress windows
- Water in the foundation, fixed before anything else
- Sound between floors
Fits: Houses with enough ceiling height, a dry foundation and room for a separate door.
Plans that start here
The Lower LevelSeparate entry, egress windows, sound-rated ceiling.Basement650 sq ft1 bed, 1 bath$___k
Owner slot From-prices set by the builder. Example only; quoted after a site visit. What moves the price
Questions
Current rules: Seattle SDCI ADU page.
Our basement gets damp. Is that a deal-breaker?
Not always, but we fix water first and show you what that costs on its own line. A unit built over a wet foundation is not a unit we will build.
Do we need a separate entrance?
A legal unit needs its own entry and safe exits. We draw both at the design stage and include them in the price.
Start with the lot.