What’s an ADU?
ADU is an acronym for Accessory Dwelling Unit. Also called: Granny Flat, Backyard Cottage, DADU (Detached Accessory Dwelling Unit) and other terms. Check your planning or zoning code for availability and current requirements, they’re frequently revised.
Are There Different Types of ADUs?
The typical range:
● Detached or freestanding. New construction on the site of an existing single family dwelling.
● Within or expansion of an existing single family residence. Like a basement conversion or addition attached to an existing single family residence.
● Conversion or expansion of an existing free-standing structure such as a garage or out-building.
What are the Area Limits for an ADU?
Every jurisdiction is different. Most freestanding ADUs are limited to a maximum area usually around 800 sf while many jurisdictions are permitting larger units. Some are encouraging development of smaller units by stipulating a small size and/or waiving some fees.
Another limit can be a percentage of the area of the primary residence. Note that the terminology and method of calculating permitted area varies by jurisdiction.
Check your planning or zoning code. Area limitations are changing rapidly due to their popularity.
Are There Other Requirements for an ADU?
Limits on height and lot placement are the norm. Some jurisdictions require some kind of design compatibility with the primary residence. Requirements are updated periodically so check for the most current.
What are the Benefits of an ADU?
● Facilitates “Aging-in-Place” aka downsizing and “Generation Swap.”
● Can produce income with a return on investment.
● Provides extra, affordable, housing on site supporting density goals.
● Leverages existing property enhancing value. Architect designs increase value.