Multigenerational Homes and Aging-in-Place ADUs: The Los Angeles Trend Reshaping Custom Builds
Los Angeles homeowners are increasingly building custom homes and ADUs to accommodate multigenerational living and aging in place. This guide outlines the essential design features for creating comfortable and private family living spaces.
Ask Los Angeles homeowners why they are building, and a growing share say the same thing: they want family under one roof, with separate front doors. Multigenerational living and aging in place are now shaping custom homes and ADUs in the Valley, the Westside and the foothills.
Key Takeaways
- Families are designing the ADU and the main house as one plan, not as two unrelated projects.
- Aging-in-place features are cheapest when they are built into the original framing and slab.
- Privacy, separate entries and separate utilities matter as much as square footage.
- Every new ADU or addition still needs plans, Title 24 compliance, permits and inspections.
Why this trend is growing
High rents, high purchase prices and aging parents have pushed families to pool resources on one lot. California's ADU laws make a second unit far easier to approve than it was a few years ago, so a rear-yard cottage for a parent or a returning adult child is now a realistic alternative to a second mortgage. See our guides on ADU plans in Los Angeles and the 2027 detached ADU changes for the rules.
Design details that define a multigenerational build
- Separate entries and sight lines. A private walkway, its own address-facing door and a window layout that avoids looking into the main house.
- Single-level living. Zero-step thresholds, hallways wide enough for a walker or wheelchair, and 36-inch doors where space allows.
- Curbless showers and blocking. Flat tile showers and solid wood blocking inside bathroom walls so grab bars can be added later without opening drywall.
- Quiet, efficient systems. A mini-split with its own thermostat, good insulation and acoustic separation between units.
- Smart-home basics. Motion lighting, video doorbells and simple controls help parents live independently. Read more in our smart home planning guide.
Plan the site and the utilities together
The biggest savings come from combining work. One electrical service upgrade, one trench for water, sewer and power, and one grading plan cost less than doing each twice. Before design starts, we check panel capacity, sewer lateral location and setbacks, which are the items that most often change an ADU budget. Related reading: electrical panel upgrades for an ADU and water service for an ADU.
Hillside and fire-zone lots
Many family compounds sit on hillside or high-fire-risk lots. Those sites may need soils reports, engineered retaining walls and ignition-resistant materials, which affect both cost and timeline. Confirm this early with a licensed contractor.
What to do first
- Decide who will live where, and how privacy should work.
- Have the lot checked for setbacks, utilities and site constraints.
- Choose aging-in-place details now, even if they are not needed yet.
- Get a fixed-price proposal that covers design, permits and construction.
Costs and timelines vary by lot and scope, so we price after a free on-site visit. Request a consultation or see our ADU and garage conversion services.
Frequently Asked Questions
What is a multigenerational home in Los Angeles?
It is a property designed for two or more generations of one family, usually a main house plus a detached ADU, a junior ADU, or a first-floor suite built for a parent or adult child.
Can an ADU be built for aging in place?
Yes. An aging-in-place ADU uses a no-step entry, wider doorways, a curbless shower, reinforced bathroom walls for future grab bars, and lever hardware. These details cost far less when planned before framing than when retrofitted.
Do I need a permit for a granny-flat style ADU in Los Angeles?
Yes. A new ADU requires plans, structural and energy compliance (Title 24) and permits and inspections from the building department, which in the City of Los Angeles is LADBS.
Should the ADU and the main house be designed together?
When both are being built or remodeled, yes. Sharing utility trenches, one electrical service upgrade and coordinated site grading usually saves money and avoids rework.
Can 1 Smart Build design and build a multigenerational property?
Yes. We handle feasibility, design, permits and construction as one licensed design-build team, and we price after walking your property.
DISCUSS YOUR PROJECT WITH 1 SMART BUILD
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