Question 1

What is an ADU?

Accepted Answer

An ADU (Accessory Dwelling Unit) is a secondary housing unit on a single-family residential lot. ADUs can be detached (standalone backyard unit), attached (addition to the main house), converted from a garage, or a JADU (Junior ADU up to 500 sq ft within existing structure). California state law requires all cities to allow at least one ADU per single-family lot.

Question 2

Do I need a permit to build an ADU in California?

Accepted Answer

Yes — every ADU in California requires a building permit regardless of size or type. zHeight handles the complete ADU permit set including architectural drawings, structural engineering, and Title 24 CF1R energy compliance report, then submits online to your city portal and responds to all plan check corrections until the permit is approved.

Question 3

Is Title 24 energy compliance included?

Accepted Answer

CF1R reports are required for new ADUs, additions and many remodels in California. zHeight prepares them in-house as part of its ADU, JADU, addition and remodel permit sets. We do not offer standalone Title 24 reports.

Question 4

What areas does zHeight serve?

Accepted Answer

zHeight serves 52+ jurisdictions across California for ADU design and permits — including San Jose, Fremont, Newark, Castro Valley, Oakland, Hayward, Sunnyvale, Santa Clara, Mountain View, Palo Alto, San Mateo, Redwood City, Berkeley, and more across the Bay Area. Residential design services are expanding nationwide.

Question 5

Does zHeight build or construct ADUs?

Accepted Answer

No — zHeight is an architecture and permit services firm, not a builder or general contractor. zHeight produces the permit drawings, structural calculations, and Title 24 energy reports, then coordinates permit approval with the city. After the permit is issued, homeowners hire a separate licensed California General Contractor (CSLB-licensed) to construct the ADU.

Question 6

How much does an ADU permit set cost?

Accepted Answer

zHeight offers a flat-fee ADU Permit Set for $7,999 — includes permit-ready architectural drawings, structural calculations, and Title 24 CF1R for a 749 sq ft detached ADU. JADU garage conversion permit sets are $4,888 flat fee for a 420 sq ft unit. Custom ADU designs and additions are quoted free at zheight.ai/get-started.

Question 7

What is a JADU?

Accepted Answer

A JADU (Junior Accessory Dwelling Unit) is a secondary unit up to 500 sq ft created entirely within the walls of an existing single-family home or attached garage. California Gov. Code §66333 allows one JADU per single-family lot. JADUs require a building permit, an efficiency kitchen, and a separate entrance. They are the most affordable ADU type because no new structure is built — only the existing space is converted.

Question 8

What is included in a Title 24 CF1R report?

Accepted Answer

A CF1R (Certificate of Compliance — Residential) documents insulation R-values, window U-factor and SHGC, HVAC system efficiency, water heating compliance, and mandatory energy measures for California residential projects. It is generated using EnergyPro or CBECC-Res software and filed with the city building permit. zHeight prepares the CF1R in-house within our permit sets.

Question 9

How long does the ADU permit process take in the Bay Area?

Accepted Answer

Design and permit set preparation takes 2–4 weeks with zHeight. City plan check review takes 4–12 weeks depending on the jurisdiction — San Jose targets 10 business days for over-the-counter ADU review; Fremont and Oakland typically take 6–10 weeks. Total permit timeline is 3–6 months. Construction (by a separate licensed GC) adds 4–8 months.

Question 10

Are there impact fees for ADUs in California?

Accepted Answer

ADUs under 750 sq ft are exempt from city development impact fees and school fees statewide under California Gov. Code §66324. ADUs 750 sq ft and over are subject to standard impact fees, which in San Jose can range $12,000–$25,000. Impact fees are paid to the city separately and are not included in zHeight's design fees.

Residential Design & Permits.
Smooth Approvals.

What Our Clients Say

What We Offer

ADU, JADU, Remodel & Addition Building Plans

Permit Processing & Approval

3D Visualization & Renders

Why Choose zHeight

AI-Powered Intelligence

Faster Turnaround

Compliance Guaranteed

Expert Team

Extensive Knowledge of Local Codes

Latest from the Blog

Owner Builder vs Hiring a General Contractor: Pros and Cons for Your Home Construction Project

Why California ADU Permits Get Rejected in 2026: The 14 Most Common Plan Check Corrections

California ADU Laws 2025: What Homeowners Need to Know

Ready to Start Your Project?

Residential Design & Permits.Smooth Approvals.