Adding a second home on your lot, without getting fleeced
If you’re reading this, you’ve probably already done the math: a detached studio in your backyard, or a converted garage, would change your life. Maybe an aging parent moves in. Maybe an adult kid gets a soft landing. Maybe you rent it out and fund the whole thing. Maybe you just want the office your house doesn’t have.
The internet is not actually helpful here. Every other result is a contractor’s marketing site. Light on numbers, heavy on “schedule a consultation.” The few real-numbers guides are buried under three paragraphs of “what is an ADU” filler.
This site exists because building an ADU is a six-figure decision and you deserve straight answers before you call anyone.
What you’ll find here
Cost guides → What ADUs actually cost, by state, by square foot, by build type. Soup-to-nuts examples with line-item breakdowns. Updated when fee schedules change.
Permit guides → What you have to file, who you file it with, how long it takes, and what trips most people up. We link to the actual forms, not somebody’s summary of the forms.
Design guides → Detached vs. attached. Garage conversion vs. ground-up. Layouts that actually work in 400, 600, 800 square feet. Floor plans that don’t waste space.
Comparisons → Side-by-side decisions: ADU or addition? Prefab or site-built? Garage conversion or detached new build? Cash or HELOC? With the trade-offs that contractor sites quietly skip.
Who this is for
Homeowners. People with a lot, a budget that’s tight enough to matter, and a real decision to make in the next 6-12 months. We assume you can read a permit form and you’d rather see the numbers than be sold to.
If you’re a builder, you’re welcome to read along. The voice here is aimed at the person paying you.
Who we are and how we make money
Right now, we don’t. There are no ads, no affiliate links, no email pop-ups, no contractor referrals. The site is a project to see if we can become genuinely useful before we figure out what to charge for. We’ll be transparent on this page when that changes.
What’s coming next
We’re publishing weekly. The first batch covers the questions homeowners actually ask first: should I convert my garage or build new? what does $300k get me in 2026? what’s the permit timeline in California? Subscribe in a few weeks when we have a list set up. For now, bookmark and check back.
The honest disclaimer
ADU costs and permit rules change. We update articles as we learn of changes, but always confirm the latest figures with your city’s planning department before you commit. We’re not your lawyer or your contractor. We’re trying to be the article you wish someone had handed you before you started.
Published guides
- ADU Cost Guide: What $300,000 Actually Buys You in 2026
A real-numbers cost breakdown for a $300k detached ADU build in 2026. What's included, where the money goes, what makes it cheaper, and what makes it more expensive. With line items, not ranges.
- ADU Permit Timeline: A State-Agnostic Walkthrough of How Long This Actually Takes
From 'we want to build an ADU' to 'we move in,' the real calendar broken into the five phases that govern the timeline. With the pitfalls that add months and the recent state laws that are taking months back.
- ADU vs. Garage Conversion: Which Is Actually Right for You?
A side-by-side look at building a detached ADU versus converting your garage. Costs, timelines, permits, and the trade-offs nobody tells you about until you're three months in.
- What a California ADU Actually Costs in 2026
A real-numbers look at ADU cost in California in 2026: Bay Area to Central Valley, what CA code adds, permit fee waivers, and financing options.
- Detached vs. Attached ADU: Which Type Actually Makes Sense for Your Lot
Detached vs. attached ADU: how costs, permits, setbacks, and resale value differ. A decision matrix for choosing which type fits your lot.
- Garage Conversion to ADU: Real Costs, by Region
what a garage conversion to adu actually costs in 2026: line items for a 400 sq ft 2-car garage, the hidden costs, regional variation, and when a detached build pencils out instead
- ADU Financing: How Homeowners Actually Pay for One in 2026
The five financing products most homeowners use to pay for an ADU in 2026, with current rates, specific lender names, and a decision tree to pick the right one.
- How Much Can You Actually Rent an ADU for in California
Rent comparables by metro, the honest cash-flow math on a $300K build, the Fannie Mae October 2025 mortgage-qualification update, and the 7-year covenant gotcha if you used state financing.
- ADU vs. JADU: Which One Fits Your Lot, Your Budget, and Your Goal
The real difference between a California ADU and a JADU: size caps, owner-occupancy rules, cost ranges, and when each one makes sense.
- ADU vs. Tiny House on Wheels: Two Different Things
An ADU is real property. A tiny house on wheels is a vehicle. That legal distinction drives everything: financing, property taxes, depreciation, and resale. Here's how the two paths actually compare.
- Prefab vs. Site-Built ADU: Real Costs, Schedules, and Financing in 2026
Modular, panelized, manufactured, or site-built — four legally and financially distinct products. What each actually costs, how long it takes, and which a conventional lender will finance.