Prefab ADUs in Solana Beach
Factory-built ADUs can shorten site time, but in Solana Beach they meet the same requirements as any ADU in the Solana Beach ADU Submittal Process and Basic Plan Requirements (June 2025).
Rules that still apply
- FAR worksheet with the 800 sq ft ADU exemption and the 60% threshold
- No ADU where more than 50 cubic yards of grading is needed
- 6 ft separation from the house (10 ft from the ADU entrance if it faces another wall)
- Same architectural style, materials and colors as the house
- Entrance not visible from the street adjacent to the front yard
- Sewer connected to the house's line on private property
Solar
The handout notes the Energy Code solar rule excludes manufactured homes, and points to HCD Information Bulletin 2020-10. Modular units built to the California Building Code are a different category, so we confirm which applies.
Delivery
Many Solana Beach lots are narrow with limited side access. Crane placement, street permits and overhead lines need checking early.
PADU vs prefab
A city pre-approved plan is a plan set, not a product. See PADU plans.
Prefab vs PADU vs custom
| Prefab or manufactured | PADU plan | Custom | |
|---|---|---|---|
| Review | Full plan check | Streamlined, site conditions still reviewed | Full plan check |
| Size | Per FAR | 800 sq ft max, 16 ft | Per FAR |
| Solar | Manufactured homes excluded from the Energy Code requirement | Per Energy Code | Per Energy Code |
| Style match | Required | Required | Required |
Sources: Solana Beach ADU handout and PADU guide.
Prefab checklist
- Delivery and crane access
- Grading 50 CY or less including the foundation pad cut outside the footprint
- Exterior can match the house
- Sewer tie-in to the house lateral
Also checked Oct 14, 2026: Solana Beach ADU Submittal Process and Basic Plan Requirements (June 2025) · Solana Beach PADU Processing Guide.
Sources, checked Oct 14, 2026: Solana Beach ADU Submittal Process and Basic Plan Requirements (June 2025).
FAQ
Are prefab ADUs allowed in Solana Beach?
Yes. They follow the same ADU rules as site-built units.
Is a prefab ADU the same as a PADU?
No. A PADU is a city pre-approved plan set. A factory-built unit can be a PADU only if its plans have gone through that program.
Do manufactured ADUs need solar?
The city handout notes the Energy Code solar requirement excludes manufactured homes. See HCD Information Bulletin 2020-10 and confirm with the CEC.