If you’re a homeowner in need of additional income, you may have considered renting out a portion of your house, but the lack of privacy has probably been the deal breaker. Many people are considering adding a separate unit onto their house, or creating one within the existing footprint.

The first thing to look at is how your property is zoned. Even if a property is zoned R2, there are many other local requirements that must be met for a second unit to be allowed.

In Santa Barbara, these include adequate lot size, parking and open yard area. Once it has been determined that a second unit is allowable, the design can begin.

When dividing a space, providing a separate entry, kitchen and bathroom for each unit are obvious necessities. Access to the washer and dryer should also be a consideration.

What may not be obvious is the need to separate the infrastructure, such as the mechanical and lighting systems. Each unit needs control of its own temperature. And you don’t want to flip a light switch in one unit and have the light go on in the other. Proper sound insulation between the units also is important.

In Santa Barbara, any exterior changes, such as a new entry door for the second unit, must be approved by the Architectural Board of Review. Once ABR approval is obtained, construction drawings must be submitted to the building department for approval.

The city might take this opportunity to require other upgrades to both the site and the building. It may be tempting to try to skip the permitting process, but the city is constantly on the lookout for illegal units, so doing so can be an expensive mistake if caught. The design and permit approval process typically takes a few months.

Adding a rental unit can significantly increase the value of a property. Creating a small unit within an existing house might cost about $100,000, but the return on that investment is relatively high when you consider the monthly rental income that it will generate.

— Elisa Garcia is the owner of Garcia Architects, 122 E. Arrellaga St. Click here to read her blog, in which she writes about architecture, design, interiors and management. Garcia can be reached at 805.856.9118 or elisa@garciaarchitects.com.