Plan F
600 SF1 bedroom / 1 bathroom. A compact option for rental, guest, or flexible multigenerational use.
Building Value
Evaluate the ADU as a build and an ownership decision.
Property review, feasibility, planning, permitting coordination, and construction organized around the way you intend to use the asset.
Why Build an ADU?
More space. More flexibility. A long-term property decision.
- Long-term rental housing
- Multigenerational living
- Housing for aging parents
- Space for adult children
- Guest housing
- Home office or flex space
- Property repositioning
- Increased usable density
UnionStone does not promise or guarantee rental income, financing approval, property-value increases, or a specific financial result. Property and financial analysis must be site-specific.
Standard Plan Reference
Start with the use case, not just the square footage.
San Diego County publishes standard dwelling-unit plans that can provide a useful reference point. Site-specific information, engineering, and jurisdictional review are still required.
Plan E
800 SF1 bedroom / 1 bathroom. A larger one-bedroom configuration for long-term living.
Plan D
1,000 SF1 bedroom / 1.5 bathrooms. More room with an added half bathroom.
Plan A
1,200 SF3 bedrooms / 1 bathroom. Prioritizes bedroom count within the County plan set.
Plan B
1,200 SF2 bedrooms / 1 bathroom. A balanced two-bedroom layout with larger living areas.
Plan C
1,200 SF2 bedrooms / 2 bathrooms. Prioritizes bathroom count and dual-suite functionality.
County plans are public reference materials, not proprietary UnionStone designs. The County states that the plans require project-specific information. Regulations and accepted plans change; verify current requirements for the property and jurisdiction.
Feasibility Process
Understand the project before committing to the project.
01
Property
Access, topography, setbacks, fire access, and development constraints.
02
Utilities
Electrical, water, sewer or septic, drainage, and service capacity.
03
Plan
Program, configuration, design path, and jurisdictional requirements.
04
Budget
Construction, design, engineering, permitting, site work, and contingency.
05
Decision
Use, rent, financing, timing, risk, and the owner's long-term objective.
What Shapes Cost
Square footage is only one input.
ADU budgets are materially affected by access, grading, utility routes and upgrades, fire requirements, structural systems, jurisdiction, finish level, and the amount of site-specific design required.
A useful budget separates vertical construction from design and engineering, permits and fees, site work and utilities, owner selections, and contingency.
Request a property conversation