ADU Floor Plan Generator — Design Your Accessory Dwelling Unit

Design ADU floor plans with AI. Create optimized layouts for guest houses, granny flats, and backyard homes with cost estimates and feasibility analysis.

Accessory Dwelling Units (ADUs) — also called granny flats, in-law suites, or backyard homes — have become one of the most popular home improvement projects in the country. Buildora IQ's ADU Floor Plan Generator uses AI to create optimized ADU layouts that maximize your available space while complying with local regulations. Our AI considers your main house position, lot dimensions, setback requirements, and local ADU ordinances to generate floor plans that are both efficient and buildable. Whether you're planning a detached backyard ADU, a garage conversion, or an attached addition, the tool produces layouts optimized for the specific constraints of your property. ADU floor plans typically range from 400–1,200 square feet and include: - Studio, one-bedroom, or two-bedroom configurations - Full kitchen and bathroom layouts - Living/sleeping area optimization - Storage solutions for compact spaces - Outdoor access and private entry design - Parking accommodation considerations Each generated plan includes cost estimates specific to ADU construction, which differs from standard home building due to utility connections, separate metering requirements, and the unique challenges of building in an existing backyard.

ADU construction costs range widely based on type, size, and location: **Detached new-build ADU**: $150,000–$350,000+ - Most expensive option but offers maximum privacy and design flexibility - Requires new foundation, utility connections, and separate systems - Typical cost: $250–$400/sqft depending on market **Garage conversion**: $80,000–$200,000 - Lower cost by reusing existing structure - Key expenses: foundation reinforcement, insulation, plumbing/electrical, finishes - Typical cost: $150–$300/sqft **Attached addition ADU**: $100,000–$250,000 - Shares wall(s) with main house, reducing some costs - Requires careful integration with existing systems - Typical cost: $200–$350/sqft **Prefab/modular ADU**: $100,000–$250,000 - Factory-built units installed on prepared foundation - Faster timeline (8–16 weeks vs. 6–12 months for site-built) - Cost varies significantly by manufacturer and customization Buildora IQ's ADU cost estimates include utility connection fees, separate metering costs, and jurisdiction-specific impact fees that are frequently overlooked in preliminary budgets.

ADU permitting has been streamlined in many states, particularly California, Oregon, and Washington. However, requirements still vary significantly by jurisdiction. **California ADU rules** (most permissive): - Allowed by right on most residential lots - No owner-occupancy requirement (for most ADU types) - Reduced setbacks: 4 feet from rear/side property lines - No minimum lot size for most ADU types - Permit fees capped for units under 750 sqft - 60-day permit processing deadline **Other states**: Rules vary widely. Some allow ADUs by right, others require conditional use permits or special exceptions. Buildora IQ's permit lookup identifies your specific jurisdiction's ADU regulations. Common ADU permit requirements: - Site plan showing ADU location relative to main house and property lines - Floor plan with room dimensions and egress compliance - Utility connection plan (water, sewer, electric, gas) - Separate address and metering (required in many jurisdictions) Buildora IQ generates ADU designs that account for these regulatory requirements, ensuring your concept is buildable within your jurisdiction's rules.