Accessory dwelling units are booming, especially in California and Texas. Whether you call it a granny flat, in-law suite or backyard cottage, an ADU needs proper plans before anyone breaks ground. Here is what to know.
What drawings does an ADU need?
At minimum, you need a dimensioned floor plan showing the unit layout, plus a site plan showing where it sits on your lot. Most projects also benefit from:
- Elevations showing what the ADU looks like from outside
- A 3D model to check rooflines, window placement and how it relates to the main house
- Photorealistic renders to visualize finishes and sell the concept to family or lenders
What ADU plans cost in 2026
- ADU floor plan: $200 to $500 depending on size (studios to 1,200 sq ft two-bedrooms)
- 3D model of the ADU: $250 to $600
- Exterior renders: $149 to $300 per view
- Complete ADU package: $700 to $1,500 for plans plus renders
Why 3D matters for ADUs
ADUs live or die on small details: ceiling height in a 400 sq ft studio, window placement for privacy from the main house, roofline matching the existing home. A 3D model catches these issues before construction, when fixes cost nothing instead of thousands.
Renders also help with the human side. Neighbors, HOAs and family members approve projects faster when they can see exactly what is being built instead of imagining it from flat drawings.
Permits: what we do and do not cover
ADU permits require construction documents that meet local code, and in most jurisdictions those need a licensed professional’s involvement. We provide the design drawings, floor plans, 3D models and visualization. We do not provide stamped permit sets or structural engineering. Be wary of any service that promises permit-ready stamped drawings without a licensed architect or engineer behind them.
Timeline
A typical ADU design package takes 2 to 3 weeks from measurements to final renders, assuming prompt feedback. If you are on a tight timeline, ask about rush delivery when you request your quote.
Planning an ADU in Texas, California or Florida? Get a free quote with your lot size and the ADU size you have in mind, and we will price your project within 24 hours.