About Prefab Cost Lab
Who writes our guides
Daniel Reyes
Editorial Researcher
Daniel compiles prefab and modular construction cost, permit, and lot-development data across the SF Bay Area. His research draws on city building department fee schedules, public permit records, and published ADU and prefab builder pricing. Guides are produced with AI-assisted drafting and human editorial review — see our editorial policy for how that works.
What this site is
Prefab Cost Lab helps Bay Area homeowners plan a prefab or modular ADU project: what it costs to build in their city, what the local permit and impact-fee process looks like, and how lot-development rules affect feasibility.
We are a research and referral publisher. We are not a builder or contractor and do not perform construction work. When you request cost details through our site, we may connect you with partner prefab and modular builders who pay us for referrals — at no cost to you. See our disclosure.
How we keep data honest
Every concrete figure on a city page — permit fees, impact fees, cost ranges, lot-development rules — must trace to a verifiable source gathered during research: city fee schedules, public permit records, or builder pricing published in our service area. Cities without verified pricing don't get a page with invented numbers; they simply aren't published yet.