Plan your backyard home with real numbers.
ADU costs, permits, loans and state rules, written plainly from public sources. Then a short list of real builders to call.
Photo: Se. Tsuchiya / Unsplash
Real builders to call, sorted by what you need
41 companies in 5 categories. No paid rankings, and paid placements are always labeled.
Are you a builder? Request a free listing
How getting quotes works
- 1Tell us about your projectYour ZIP, what you want to build and when you want to start. It takes about a minute.
- 2We read it and match youYour request comes to the BackyardStack inbox, and you get a confirmation email. Then we connect you with builders from this directory who serve your area. We do not sell your details.
- 3Compare and decideBuilders contact you directly. Compare their quotes and pick one, or none. It is free for homeowners.
Everything to know before you call a builder
Each guide is a few minutes long and links every number to a public source.
Start here
What an ADU really costs, and where the money goes
The first guide to read. Where a typical budget goes and which choices move it most.
Read the guide CostsFive real ADU projects, broken down line by line
MoneyHow people actually pay for an ADU
Design and buildPrefab vs site-built ADUs
MoneyADU rental income and payback
Rules and permitsHow long ADU permits really take
Design and buildJADU, attached or detached
Design and buildHow big and how tall can your ADU be?
Rules and permitsSetbacks, HOAs and deed restrictions
Site workUtilities, sewer and power
Work out your numbers in a few minutes
Built on the same survey and public data our guides use. Change any default to match your project.
Which ADU fits you?
Six quick questions that point you to a detached unit, a conversion, an attached ADU or a JADU.
Take the quizBudget estimator
A cost range for your project built from owner survey data, with defaults you can edit.
Estimate a budgetTimeline builder
A printable plan from first sketch to move-in, using phase lengths from a public pilot program.
Plan the timelineFree to use, no account needed.
Browse by type
41 builders, lenders and specialists, each checked against its own website and described in its own words.
Quick facts, sourced
ADUs permitted in California in 2024, up from 1,336 in 2016.
Source: California HCDmedian cost to build an ADU in California's statewide owner survey.
Source: UC Berkeley CCImedian monthly rent for an ADU in the same survey.
Source: UC Berkeley CCIUS single-family properties with ADUs found in listing data.
Source: Freddie MacThe Backyard Letter
One short email when we publish something new: a guide, a rule change in your state, or a public cost report worth reading. Every item links to its source. Free, unsubscribe any time.
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