Most of the attached ADUs we build in Cupertino are for family. A parent who needs to be nearby but does not want to share a kitchen. An adult child who is working locally and saving. The appeal of an attached unit in that situation is exactly the thing people worry about with detached units, which is distance.
Sharing a wall means someone can knock rather than walk across a dark yard. For an aging parent that is not a small consideration.
An attached accessory dwelling unit touches the main house but functions as an independent residence.
Homeowners often start by describing a suite. That is a different project under different rules, and we will tell you plainly which one you are actually asking for.
If a parent is moving in, the layout decisions made now determine whether the unit still works in ten years. We build in a curbless shower, doorways wide enough for a walker, solid blocking in the bathroom walls so grab bars can go in whenever they are needed, lever hardware, and a threshold at the entry that does not become a trip hazard.
Done at framing, none of that is expensive or institutional looking. Retrofitted later, all of it is disruptive.
Code requires fire rated separation between an attached ADU and the main house. Satisfying that rating does not by itself give you sound isolation, and sound is what determines whether two households living wall to wall stay comfortable with each other.
We insulate the shared cavity, decouple framing where the layout permits, and route plumbing so the unit's plumbing noise is not transmitted into your bedrooms. Our approach to ADU construction covers how we detail these assemblies.
The economic case for attached units rests on shared services. The limit is capacity. Cupertino homes of a certain age were never wired for a second kitchen and a second full set of appliance circuits, so a panel upgrade is common. We check it early and price it openly rather than letting it appear halfway through.
Water and sewer are usually simpler, tying into existing laterals where the sizing supports it, which we verify rather than assume.
An attached ADU is an addition that happens to contain a complete dwelling. New foundation edge, framing tied into existing framing, a roof line that meets the old one and stays watertight, and an envelope that performs through a Bay Area winter.
We build additions with the same crews and standards, which is why this transition is natural for us. Our home addition services page covers the overlap. If you are still deciding whether an ADU suits your property, our explainer on what an ADU house is is a reasonable starting point.
Whether an attached unit is right depends on your wall, your panel, and your setbacks. Contact our team and we will walk your Cupertino property and give you an honest read.
.svg)