Accessory Dwelling Units (ADUs) have been around for a long time, often referred to as backyard cottages, granny flats, or in-law units Although useful, many were built without building permits because of the often overly complicated and restrictive rules surrounding them. In 2020, in an attempt to increase the stock of affordable housing, the State of California mandated changes making them much easier to permit and build statewide. The rules within this mandate override most of the restrictions individual municipalities previously had in place prior to 2020. These new units can be built either within the existing footprint of the home or by converting an existing secondary structure like a garage or by building a brand new stand-alone structure. The demand for these units has increased markedly, both as a result of the easing of the rules, as well as homeowners rethinking what a home’s function means to them.

Uses for ADUs that I have discussed with homeowners:

Multi-generational/Family

• A place to care for elderly parents instead of a retirement home where the next generation can help care for them but they have their own space
• Transitional housing for adult children unable to afford the high price of Bay Area housing or trying to save money to enter the housing market on their own
• Housing for the retired generation to downsize into, allowing their adult children with kids, who need more space, to move into the main house

Flex Space

• Dedicated virtual office/school room
• Hobby Room, Teenager gaming space – separate from the house
• Space for family to come and stay, extended if needed, without imposing on the main house
• If tied to garden space it can be used as an extension of entertaining space

Income/Investment

• Rental space to help offset income insecurity
• Help fund future or current retirement/investment
• Add equity to the property
• Provide a home base for extended travel by renting the main house but maintaining housing in the Bay Area.

Types of ADUs – Stand Alone Structures

Pre-Fabricated

There are several companies that offer ADUs that are constructed in an offsite factory and then delivered largely complete and set on a new foundation. This option is not necessarily a big cost savings but can shorten the length of disruption on site, however there are limitations due to site access.

Pre-Designed

One of the options Kodiak Construction offers are pre-designed units which provide both a cost and time savings as compared to an original design. Choosing from a selection of ADUs that have already been designed and estimated streamlines the preconstruction process by sharing the design costs amongst multiple users. Although there are several options, modifications are limited to predesigned packages without incurring significant upcharges.

Unique Designs

Creating a unique design provides the most flexibility to address all of the homeowner’s wants, which might be the most important factor, but the process comes with both a time and financial cost. The design process can take months, between the back and forth between architect, homeowners, and the structural engineer. Additionally, Kodiak Construction should also be providing cost analysis to help keep the project on budget. This process is more expensive than a predesigned unit because each new unit gets the focused attention of the architect without the benefit of cost sharing across multiple projects. Once the project is designed, approved and estimated, construction timing is not too dissimilar than a pre-design unit.

Existing Structures

It might be desirable to convert either a standalone structure or use existing space within the primary home. This option requires hiring design professionals to navigate the benefits and restrictions of the existing structure. This choice might be due to cost or trying to maintain as much of the exterior space as possible. Often, utility connections are less expensive by building onto an existing structure as compared to building a stand-alone building.

Utilities

Regardless of how the ADU is designed and built, connections to electrical, water and sewer are required and are unique to each property. The pathway between the existing services and a freestanding location can be complicated by distance, existing hardscape, and/or vegetation, all of which will impact the final cost. These connections are usually simpler and less expensive for ADUs that are within the existing structure’s envelope because distances are shorter and trenching is not required.