Service 05 • Interior & Attached
Junior ADU (JADU) & Attached Extensions in Orange County.
Create a compliant Junior ADU (up to 500 sq ft) within your existing home footprint or build an attached suite extension. Ideal for aging parents, college students, or private guest quarters with lower upfront construction investment.
Typical Timeline
8 to 12 Weeks Build Time
City Permits
100% In-House
Contractor License
Class B Alliance
2026 COST BREAKDOWN • LINE-ITEM TRANSPARENCY
Estimated Line-Item Costs for Junior ADU (JADU) & Attached Extensions
Real budget allocations across architectural drawings, city permit fees, utility trenching, and turnkey construction in Orange County.
| Cost Component | Typical Range | Key Details & Code Notes |
|---|---|---|
| Architectural Plans & Structural Engineering | $6,000 - $9,500 | Includes Title 24 energy calculations & 3D renderings |
| Municipal Plan Check & City Permit Fees | $2,500 - $5,000 | Exempt from school impact fees if under 500 sq ft |
| Plumbing Trenching & Sewer Utility Connection | $8,000 - $18,000 | Independent subpanel & dedicated water tie-in |
| Structural Foundation & Framing Scope | $35,000 - $85,000 | Engineered slab pour or garage envelope retrofit |
| Interior Finishes, Kitchen & Bath Turnkey | $28,000 - $55,000 | Quartz counters, mini-split HVAC & custom cabinetry |
SCOPE SPECIFICATIONS
What's Included in Your Single-Contract Scope
Up to 500 sq ft space with private exterior entranceFull architectural compliance and licensed Class B construction oversight.
Efficiency kitchen & full private bathroomFull architectural compliance and licensed Class B construction oversight.
Seamless architectural blending with main residenceFull architectural compliance and licensed Class B construction oversight.
Fastest municipal permit approval pathwayFull architectural compliance and licensed Class B construction oversight.
Request Your Junior ADU (JADU) & Attached Extensions Quote
Get exact line-item estimates and municipal permit review details for your property within 1 business day.
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