What is a multigenerational or next-gen home and how do you design one?

A multigenerational home, sometimes sold as a next-gen home, is a single house designed to hold two or more adult generations living together, such as grandparents, parents, and adult children. The hallmark is a private suite: its own bedroom and bathroom, usually a separate living area, and often a private entrance and a small kitchen or kitchenette. You design one by balancing two needs at once, privacy for each generation and easy shared family life, while planning the suite so it works for someone who may age in it.

This is a growing way to build in Arizona, not a niche. The U.S. Census Bureau reports that "there were 6.0 million U.S. multigenerational households in 2020," up from 5.1 million in 2010, and that such households "made up 4.7% of all U.S. households but 7.2% of family households." The trend is strong across the Sun Belt, and metro Phoenix families build for it to care for aging parents, house adult kids in a costly housing market, and share the load of a big home. Below is how the design works and the Arizona rules that shape it.

What makes a home multigenerational

A multigenerational home is defined by a self-contained private suite inside or attached to the main house, designed so a second generation can live with real independence. The Census Bureau counts a multigenerational household as "three or more generations under one roof," and the architecture follows that idea: one roof, but more than one private living zone. The suite usually includes:

• A private bedroom and full bathroom. The non-negotiable core. The bathroom should be roomy enough to make accessible later.
• A separate living or sitting area. A space to relax, watch TV, and host without using the main living room.
• A private entrance. A dedicated door to the outside so the suite's residents come and go on their own schedule.
• A small kitchen or kitchenette. Often a sink, a refrigerator, a microwave, and counter space. A full second kitchen turns the suite into something closer to a separate dwelling, which has code and tax effects covered below.

The difference between a multigenerational suite and a true second dwelling is mostly the kitchen and the entrance. A suite that opens off a shared hallway with no kitchen reads as part of the main home. A suite with its own outside door and a full kitchen starts to look like an accessory dwelling unit, or casita. Our guide on casita versus guest house versus ADU explains where those lines fall, and it matters for permits and property taxes.

How to design the private suite

Design the suite around privacy, independence, and aging in place, because the people who live in it want their own space and may need it to adapt over time. Start with location. Put the suite at one end of the house or over the garage, with a sound buffer of closets, a hallway, or a laundry room between it and the main bedrooms. That separation is what makes shared living comfortable instead of cramped.

Build the suite for accessibility from the start, even if no one needs it yet. The cheapest time to make a home age-friendly is during the original build. Practical moves are simple. Add a no-step entry at the suite's private door. Use wider doorways of 32 to 36 inches for a walker or wheelchair. Put in a curbless shower with blocking in the walls for future grab bars. Add lever door handles, and keep at least one bedroom and full bath on the ground floor. If the suite is upstairs, the home may be a candidate for an elevator, which our guide on home elevators in Arizona covers.

Plan the shared and private boundary carefully. Many families want the suite to connect to the main house through an interior door that can be locked from both sides, plus the separate exterior entrance. That gives flexibility: open the interior door for daily family life, lock it for privacy or when renting the suite later. Separate climate control helps too, since an older parent often wants a warmer room than a teenager does. A dedicated mini-split or a separate HVAC zone lets each side set its own temperature, which also fits the desert cooling strategy in our guide on designing a cool Arizona home.

Arizona rules: kitchens, entrances, and ADUs

In Arizona, adding a full second kitchen and a separate entrance can turn a multigenerational suite into an accessory dwelling unit, which changes the permitting and may raise your property taxes. A bedroom, a bathroom, and a sitting area inside the main home are simply rooms. Add a full kitchen and a private entrance and the city may classify the suite as an ADU, a self-contained second home on the lot. That is not a problem, but it is a decision to make on purpose, because ADUs carry their own rules.

Arizona has pushed cities to allow ADUs. Under A.R.S. 9-461.18, larger municipalities must permit at least one accessory dwelling unit on lots with a single-family home, and A.R.S. 11-810.01 extends a similar requirement to counties. The statutes set the framework, and each city writes the details: size caps, setbacks, parking, and whether the unit can be rented. Smaller towns like Carefree, Cave Creek, and Fountain Hills sit under the population thresholds and set their own rules. Our overview of Arizona ADU requirements and the city-by-city guides walk through the specifics.

Two practical points shape the choice. First, property taxes: adding a full second dwelling can raise your assessed value, while a suite that is just extra rooms in the main home has less effect. Our guide on whether a casita raises property taxes covers it. Second, future rental: if you might rent the suite someday, building it to ADU standards now, with the separate kitchen, entrance, and metering, keeps that door open. If you never will, a simpler suite without a full kitchen avoids the extra permitting. Decide the use first, then design and permit to match.

Is a multigenerational home worth building?

A multigenerational home is worth building when your family genuinely plans to share it, because the design pays off in care, cost-sharing, and flexibility that a standard floor plan cannot match. For families caring for aging parents, it keeps loved ones close while preserving everyone's privacy, which is the main reason the model is growing across Arizona. For families with adult children or the cost of separate housing in mind, sharing one well-designed home spreads the expense of land, a roof, and a build across more people.

The flexibility is the quiet advantage. A well-designed suite can house a parent now and an adult child in a few years. It can hold a guest or caregiver after that, and a rental tenant later if the city allows it and you built to ADU standards. That adaptability protects the home's value, because the next buyer may want exactly that space. The trade-off is upfront cost and careful design: a second suite adds square footage, a second bathroom, possibly a second kitchen and entrance, and the accessibility features that make it last. Plan it with your builder during the design phase, decide early whether the suite is an ADU or just rooms, and the multigenerational home becomes one of the most practical luxury features you can build in Arizona.

Building with Jematell Homes

Desert-smart design and systems are standard on every home we build. We would rather answer your questions before you build than after, so get in touch any time.

Sources

• U.S. Census Bureau: Several Generations Under One Roof (multigenerational households, 2020)
• A.R.S. 9-461.18 (Accessory dwelling units; municipal requirements)
• A.R.S. 11-810.01 (County accessory dwelling units)