Step-up Construction: ADU Building Services in San Jose
Step-up Construction is a licensed residential construction company based in San Jose, specializing in the planning and building of accessory dwelling units (ADUs). As an experienced ADU contractor operating within San Jose's regulatory environment, they work with homeowners through the full process of developing ADUs — from initial site assessment through to project completion.
Building an ADU in San Jose involves navigating a complex set of costs, regulations, and design requirements that differ from other Bay Area jurisdictions. Step-up Construction focuses on helping homeowners understand these variables before committing to a project.
Types of ADU Projects Step-up Construction Handles
Step-up Construction works across the main ADU construction types available to San Jose homeowners:
- Garage Conversion ADUs: Converting an existing garage into a livable accessory dwelling unit is typically the most cost-effective approach. Costs generally range from $80,000 to $200,000, depending on the condition of the existing structure and required upgrades such as electrical panel work, which can add $2,500 to $4,000.
- Attached Addition ADUs: These units are built as extensions of the primary residence and typically cost between $150,000 and $300,000. They involve roof modifications, exterior wall integration, and fire separation requirements between the main home and the new unit.
- Detached Backyard ADUs: Standalone structures require full infrastructure installation — new foundations, dedicated utility connections, and independent HVAC systems. Costs range from $200,000 to $475,000, depending on size and finish level.
As a general rule, larger ADUs tend to offer better value per square foot. Many fixed costs — permit fees, utility connections, and foundation work — remain relatively constant regardless of unit size, making larger units more cost-efficient on a per-square-foot basis.
Navigating San Jose's ADU Regulations
San Jose's ADU regulations are governed by Title 20 of the Municipal Code, incorporating state laws such as SB 9 and AB 1033 alongside local amendments. Step-up Construction conducts site assessments early in the process to identify regulatory factors that could affect timelines or costs.
One important threshold to understand is the 750 square foot rule. ADUs exceeding 750 square feet trigger School Impact Fees of approximately $4 to $5 per square foot for the area above that threshold. For this reason, many projects are designed at 749 square feet to maximize usable space while avoiding additional fees.
Zoning and setback requirements also vary by district. Standard setbacks typically require a five-foot separation from property lines, though this depends on the specific zoning classification of the lot. Certain properties face additional review requirements, including those located in:
- Planned Development Zoning Districts
- Flood Zones A, AE, AH, or AO
- Geohazard or Seismic Hazard Landslide Zones
- Wildland Urban Interface (WUI) Areas
Properties in these categories cannot use expedited permitting pathways and may require additional studies, engineering reports, or fire-resistant construction standards.
Beyond construction costs, San Jose ADU projects carry notable soft costs. Architectural services range from $2,000 for basic plans to over $40,000 for custom designs. Structural engineering typically adds $3,000 to $5,000. Step-up Construction often recommends pre-approved plan sets as a way to reduce both design costs and permitting timelines, potentially saving $10,000 to $20,000 in architectural fees.
Permit and impact fees in San Jose are among the higher ones in the Bay Area. Building permit and plan review fees typically range from $8,000 to $15,000 or more, depending on project valuation. Utility connection fees add another $2,000 to $7,000. A Title 24 Energy Compliance report — required for all new construction — costs approximately $245 but requires early coordination to avoid design changes during permitting. It's also worth noting that San Jose charges a 2.66% processing fee on credit card payments for permits, which can be avoided by paying via check or wire transfer.
For detached ADUs, site preparation costs vary considerably. Excavation ranges from $1,300 to $5,000, and grading can add another $800 to $5,000. Sloped lots can increase overall construction costs by roughly 25% due to additional grading and potential retaining wall requirements. Concrete slab foundations for standard ADUs typically cost between $2,400 and $30,000 depending on size and soil conditions.
Step-up Construction works as an ADU builder and accessory dwelling unit builder across San Jose, helping homeowners understand the full scope of costs and regulatory requirements before breaking ground.
