21 Issues Found in Prefab ADU Plans—Including Critical Property Conflicts
APN inconsistencies, easement encroachment, and California Building Code violations—surfaced before permit submission.
The Project
A prefabricated ADU (Accessory Dwelling Unit) project in California using manufacturer-provided plans adapted for a specific site. InspectMind reviewed the combined drawing set and identified fundamental conflicts in property identification, easement encroachment, dimensional discrepancies between manufacturer specs and site plans, and California Building Code violations— issues that would have caused permit rejection and costly redesign.
Sample Findings
Project Data shows APN 684-16-022, but Site Plan labels the development lot as APN 684-16-023—a fundamental contradiction in identifying the project site.
Building setback at 9.6' places structure 10.4 feet inside a recorded 20' Light and Air Easement—will be rejected at plan check.
Site plans show 44'-0" ADU length, but manufacturer plans sum to 42'-2" and title blocks reference "14X42" model—affects foundations and setbacks.
Note specifies 26" bridge blocks for 24" O.C. truss spacing—physically impossible since blocks are longer than the bay spacing.
Exterior doors sit atop 18" stem wall with no landings, stairs, or ramps shown—occupants cannot safely exit the building.
Fuel-burning water heater and furnace present, but only smoke detectors shown—no CO detection as required by CBC Section 915.1.1.
Issue Categories
Site & Property Identification
APN conflicts, property boundaries, easement encroachments
Code Compliance
Egress, accessibility, door widths, CO detection
Dimensional Conflicts
Plan vs. manufacturer specs, impossible framing dimensions
Plumbing & MEP
Drain sizing, fitting conflicts, cleanout adequacy
Value Delivered
"The APN conflict and easement encroachment would have killed this project at plan check. Finding these issues before submittal saved us months of redesign."
— Project Team