How it works
How ADUStack works.
Each home is its own project. The cohort is how you plan it with more clarity, more support, and fewer surprises.
Your journey, in four steps
- 1Join free.
Your address and preferred size. No deposit, no obligation.
- 2Your cohort forms.
Building can begin once three homes in your cohort have signed agreements.
- 3See every cost.
Your site review, design, and pricing, all before you decide.
- 4Build.
Sign with an independent licensed contractor; we coordinate the rest.
How a cohort works
Up to ten Bay Area homeowners within about 50 miles of each other, planning similar ADUs. We coordinate the rest.
Same plans. Standard designs, so bids can be compared line by line.
Shared materials. Sourced together and priced before you sign.
Vetted contractors. Licensed partners we've worked with for years, chosen for quality work and reliable timelines.
Your price holds. Building starts at three signed homes, and the Founding Cohort price doesn’t go up as more homes join.
Savings are a goal we measure, not a guarantee. Every property still has its own site review, approvals, and contract.
Who does what
Clear responsibilities, written down before anyone commits.
ADUStack
- Organizes your Bay Area cohort
- Coordinates design and project workflows
- Sources selected materials and shows their pricing
- Keeps costs visible, including what's still uncertain
Your licensed contractor
- Signs the construction agreement directly with you
- Builds, supervises subcontractors, and passes inspections
- Provides the warranties written into that agreement
You
- Decide whether to proceed after your site review
- Choose and sign with your contractor
- Can leave the cohort at any time before signing
Questions
Does joining commit me to building?
No. Joining is free, with no deposit and no obligation. You decide whether to proceed after your site review, when you can see the design, costs, and contractor terms.
Does ADUStack supply materials?
For selected items, such as prefab kits and finish materials, ADUStack coordinates purchasing for the cohort. You'll see exactly what's supplied and what it costs before you sign anything.
What's a Founding Cohort?
The first Bay Area cohort. Founding Cohort homes start at $325,000 for the 749 sq ft plan and $425,000 for the 1,199, covering design and coordination, the foundation, and the home itself. City fees, utility connection fees, and solar panels aren’t included because they depend on your city and site. Email info@adustack.com and we’ll estimate them for your property.
Who can join?
Homeowners anywhere in the nine-county Bay Area. Each cohort groups homes within about 50 miles of each other, so you don’t have to wait for neighbors in your own city, and crews stay close.
Do you have to reach ten homes before building?
No. Construction can begin once three homes in a cohort have signed agreements. The cohort keeps growing to up to ten homes, and the Founding Cohort price doesn’t go up as more homes join.
What happens when a cohort is full?
Each cohort holds up to ten homes. When one fills, the next Bay Area cohort opens. You can follow progress on Who’s Building.
What's a standard site?
Starting prices include utility trenching up to 50 ft from your home’s connection points, a level lot with workable access, and a slab foundation on typical soils. Longer trenching, tight access or slopes, difficult soils, and electrical or sewer upgrades are disclosed after your feasibility study, before you commit.
Can I add a loft or build a two-story ADU?
Yes, as an upgrade where your city’s height limits allow. Lofts and second stories change the design, structure, and cost, so we price them per project after your feasibility study.
Can the ADU go above my garage?
Yes. An ADU above a garage is handled as a custom project. You can still join a cohort and benefit from shared coordination and materials, with added costs for strengthening the existing garage, the roof, stairs, and design work. We price it after your feasibility study.
Why does my ADU need solar panels?
California’s Energy Code requires solar panels on newly built detached ADUs, sized to the home. The panels can go on the ADU or be added to an existing system on your main house. Solar isn’t included in our starting prices because its size and cost depend on your home and site; we include it in the estimate for your property.
Will there be other sizes?
Yes. We’re also developing 500 and 1,000 sq ft plans. Pricing is TBD based on interest: choose one of those sizes when you join, and demand decides which we develop first.
Why do you ask for my address?
It places you in a Bay Area cohort, lets us check your lot, and prepares your site review. Your address stays private: it’s never shown publicly, and the Who’s Building map only places a dot near your ZIP code. You can also try Check Your Lot to see an ADU on your lot.
What will the ADU look like?
Both plans are being finalized. Images on this site are conceptual renderings. Members see floor plans and finish options before any commitment.
Ready when you are
Free to join. No deposit. No construction commitment.
Join the Founding Cohort Check Your Lot