Can ADUs Be MultiStory? A Comprehensive Guide

If you’re researching ADU Construction Near Me (Santa Rosa), you’re probably wondering: can ADUs be multistory? The short answer: yes, you can build a twostory ADU in Santa Rosa but there are important rules and design considerations to know.

Before you start ADU construction near me in Santa Rosa, let’s go over everything you should know about building a multistory ADU.

What Is an ADU?

An Accessory Dwelling Unit (ADU) is a fully independent living space, complete with kitchen, bathroom, sleeping, and living areas, built on the same property as a primary home. ADUs offer flexibility for extended family, guests, or rental income.

TwoStory ADU Regulations

In Santa Rosa, you can build a twostory ADU up to 1,200 sq ft, with a maximum height of 27 ft. Onestory units are capped at 16 ft, while twostory units can be 16–27 ft tall.

Detached ADUs are typically allowed within these square footage and height limits. Attached ADUs must also comply, often giving flexibility to match the primary residence or reach the stated floor space limits.

Setbacks and Site Placement

Santa Rosa requires at least 4 ft side and rear setbacks for both attached and detached ADUs. For twostory sections, setbacks may need to increase to 8 ft, depending on zoning and development standards. Additionally, front and corner lot setbacks vary based on zoning district.

Parking and Utility Considerations

A single offstreet parking space is usually required, unless exemptions apply, such as transit proximity, historic district location, or ADU size under 750 sq ft. Internal conversion ADUs and small units often avoid this requirement.

Utility connection fees may be waived for ADUs 750 sq ft or smaller, or for junior ADUs, easing some of the cost burden.

Design Considerations for TwoStory ADUs

Building up offers several advantages:

But twostory designs also add complexity: stair structure, load-bearing walls, HVAC distribution, and fire-sprinkler installation in larger units.

Designers must also consider privacy for neighbors, for example, using obscured windows or elevated placement, and ensure material/architectural compatibility with the main house.

Permitting and Approval Process

Santa Rosa offers a streamlined 60-day permit review window. Using pre-approved or plan-review services can help speed up approvals.

Planning a TwoStory ADU? Here’s a Quick Checklist:

  • Confirm property zoning and allowable ADU types
  • Ensure setbacks (4–8 ft) and height (max 27 ft) compliance
  • Plan parking or confirm exemption
  • Incorporate fire, privacy, and utility standards
  • Apply using pre-reviewed plans and finalize building permit

Ready to Start? Call Sightline Builders Today

If you’re looking into ADU construction near you in Santa Rosa and considering a multistory build, Sightline Builders can guide you from design to final inspection. Call us today at 707-892-0671 or contact us online now to schedule your consultation. Let’s build a smart, stylish, and compliant ADU that maximizes your space and value!