Guide
What homeowners need to know.
Feasibility comes first
Check city, lot, setbacks, utilities, access, project type, and rough budget before design hardens.
Budget should shape design
Ignoring budget until after drawings is how homeowners buy very expensive disappointment.
Construction pricing needs documents
Bids become meaningful when scope, drawings, materials, site work, and utility assumptions are comparable.
Cost table
Use ranges until scope is real.
| Item | Planning range | Why it moves |
|---|---|---|
| Feasibility | $1k-$5k+ | Can prevent bad project paths early. |
| Permit-ready design | $15k-$45k+ | Depends on engineering, city, and scope. |
| Construction | $120k-$600k+ | Varies by ADU type and site conditions. |
Mistakes
Avoid these expensive shortcuts.
- Designing first and asking budget questions later.
- Not assigning responsibility for permit corrections.
- Letting construction scope drift from the approved plans.
FAQ
Fast answers.
Why use design-build for an ADU?
It can reduce handoff risk by coordinating feasibility, drawings, budget, permit review, and construction earlier.
Sources