Ready-Made ADU Plans

What a ready-made ADU plan is

An accessory dwelling unit (ADU, sometimes called a granny flat or backyard unit) is a second, smaller home on a lot that already has a house. A ready-made ADU plan set is a design for one of these units that has already been drawn and resolved, then offered as a package. Because the design is done, it can be sold for a set price instead of a custom design fee — and you start from a considered layout rather than a blank page.

A plan set describes the building itself. It does not, on its own, account for everything your specific property and jurisdiction require. Think of it as the design layer, with site-specific engineering and local details added on top.

When a ready-made ADU plan fits

• Your lot is relatively regular, with room for a detached unit or a straightforward conversion.
• You like one of the available layouts closely enough that only minor changes are needed.
• You want to move toward permitting sooner by starting from a drawn design.
• You are comfortable adding the site-specific work your city or county requires.

If your lot is steep, unusually shaped, or tightly constrained — or if you want something bespoke — a fully custom ADU design often serves you better. Our look at whether pre-approved ADU plans are worth it and the guide to six things to check before you design an ADU help you decide.

Ready-made vs. a city "pre-approved" ADU program

These are not the same thing. A ready-made plan from a designer is a design you can buy. Separately, some California cities and counties run their own pre-approved or pre-reviewed ADU plan programs. Whether such a program exists for your address, and whether a given plan qualifies, depends on your jurisdiction and changes over time. Always confirm the current rules with your local building and planning department. The California Department of Housing and Community Development publishes statewide ADU information; for the City of Los Angeles see LA City Planning and LADBS, and for unincorporated Los Angeles County see LA County Planning.

What still needs to be handled for your property

Regardless of how resolved a plan is, items that depend on your actual lot are added separately — for example a foundation designed for your soil and slope, utility connections, and any detail your jurisdiction specifically asks for. How much of this is needed varies by property. The journal entry on what changes still need an architect explains the usual line between a stock design and site-specific work.

ADUs across our service areas

Kevin Cohen Design works with homeowners across Los Angeles, Orange, and San Bernardino counties, plus Bakersfield, Simi Valley, Porter Ranch and the wider San Fernando Valley, and Sun Valley. ADU rules are set at the state level and then applied by each city or county, so the specifics differ from one jurisdiction to the next — a City of Los Angeles lot, an Orange County city, and a Kern County address can each be handled differently. See the service-areas overview for local context, and always confirm current requirements for your exact address.