House & Timber Plan Co.

Collection

ADU & Guest House Plans

Self-contained backyard homes with their own entry, kitchen, bath, and laundry. Ideal as guest houses, in-law cottages, home offices, or rentals.

Plans

300 plans available

About This Collection

ADU & Guest House Plans

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Design Your Own

An accessory dwelling unit (ADU) is a small, self-contained home on the same lot as a main house. House & Timber Plan Co.'s ADU and guest house plans include everything needed for independent living: a private entry, a full kitchen, a bathroom, laundry, and a living area, in footprints from about 400 to 1,200 square feet.

ADUs are popular as guest houses, in-law cottages, home offices, and long-term rentals. Many cities have relaxed their rules to encourage them, making a backyard cottage one of the most practical ways to add housing and income to a property.

Our ADU plans keep layouts open and simple, combining kitchen, dining, and living into one bright room, with one or two bedrooms. Compact, rectangular footprints help them fit behind or beside an existing house.

ADU plans start at $99 with instant PDF download. ADU rules on size, height, and setbacks vary by city, so check with your local planning department before you build. Each plan set includes floor plans, exterior elevations, a roof plan, sections, and an electrical layout, ready for your builder.

Common Questions

FAQ

What is an ADU?

An accessory dwelling unit is a second, smaller home on the same lot as a primary house, with its own kitchen, bathroom, and entrance. It's also called a guest house, backyard cottage, granny flat, casita, or in-law unit.

Can I build an ADU on my property?

It depends on your city or county. Many areas now allow ADUs, but rules on size, height, setbacks, parking, and owner occupancy vary. Your local planning department can tell you what's allowed on your lot.

How big can an ADU be?

Local limits vary, often from around 800 to 1,200 square feet. Our ADU plans range from about 400 to 1,200 square feet.

Can I rent out an ADU?

In many areas, yes. ADUs are a common source of rental income. Check your local rules, since some places restrict short-term rentals or require the owner to live on the property.