ADU House Plans — Rental Income, Multigenerational Living, and More
Accessory dwelling units — also called carriage houses, backyard cottages, and in-law suites — are one of the smartest things you can add to a property. Browse our curated collection of ADU plans, designed for the way people actually use these spaces.
Built for Your Property. Designed for Your Life.
Properties with ADUs are valued an average of $349,000 higher — and the right ADU can cover up to 30% of your mortgage costs through rental income alone. Whether you're building a carriage house above a garage, a standalone backyard cottage, or a detached in-law suite, our ADU collection is designed to make the most of your lot without overwhelming it. Plans range from compact studios to two-bedroom carriage houses, with styles spanning Modern Farmhouse, Mountain Modern, and Contemporary.
Every plan here is thoughtfully scaled — attractive enough to command strong rental rates, efficient enough to build without breaking your budget, and versatile enough to serve as a rental unit today, a multigenerational suite tomorrow, or a home office when you need it. All plans meet 2018 IRC standards and are available in PDF or with CAD files for modifications.
One Structure. Endless Uses.
Rental Income & Property Value
Add a rentable unit to your property and put your equity to work. ADUs are in high demand as long-term rentals and short-term stays alike — and properties with ADUs are valued significantly higher than comparable properties without them. Our most popular ADU plans are designed with rental appeal in mind: attractive exteriors, efficient layouts, and the kind of curb appeal that photographs well on every listing platform.
Multigenerational Living
Keep aging parents close without giving up anyone's privacy. Build a comfortable, independent space for an adult child who's saving to buy, or create a permanent home base for family members who visit often. An ADU gives everyone their own front door — and a way to stay connected without living on top of each other.
Home Office, Studio, or Guest Suite
Some of the best ADUs never see a paying tenant. A private studio with a door that actually closes. A guest suite that gives visitors real privacy. A workshop, art studio, or home gym that doesn't take over your garage. If you have a reason to want a well-designed outbuilding on your property, our ADU collection has a plan for it.
Plans Worth Starting With
Three of our most popular ADU plans — a great starting point for any lot or use case.
Our ADU House Plans
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Hillside & Walkout Basement House Plans
ADU plans for sloped lots — and full homes that turn hillside terrain into stunning multi-level living.
Mountain House Plans
Our full catalog of mountain home designs — from compact retreats to luxury lodges.
Single-Level Plans
Open layouts, main floor living, and outdoor spaces that actually get used — in styles from mountain farmhouse to contemporary lodge.
Browse the full Rocky Mountain Plan Company catalog across all styles, sizes, and use cases.
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