834 sq ft ADU Plan – Permit Ready

A 834 sq ft two-story one-bedroom ADU with separated ground-floor living and upper-floor private bedroom. The layout configures 1 bedroom and 1 bath within a clean, code-aware envelope. Practical on narrow infill lots where a single-story footprint of equivalent area would consume too much usable yard. The plan includes a covered porch.

Front 3D isometric rendering of a 834 sq ft 1-bedroom 2-story ADU plan in California — Exterior rendering of the 834 sq ft permit-ready ADU plan designed as a detached backyard cottage.

Plan A21-834 Specifications

Base area	834 sq ft
Bedrooms	1 Bedroom
Bathrooms	1 Bath
Stories	2-Story
Ridge height	19.83 ft
Ceiling height	8.5 ft
Roof slope	6:12
Covered porch	46 sq ft

Code & Engineering

This 834 sq ft 1-bedroom two-story ADU is delivered as a complete architectural plan set for permit-ready construction in California, developed against the requirements of Government Code §65852.2 and the supporting provisions in §65852.22.

The architectural plan set includes the floor plans for both stories, exterior elevations on all four sides, building sections, and dimensioned framing intent. The design is developed to meet the current California Residential Code (CRC) and is intended for structural design under ASCE 7 for loading and the National Design Specification (NDS) for wood construction.

Specific structural details — wall framing, sheathing, shear-wall locations, holdown selection, and connection design — are delivered through the optional Structural Set package and sized to the seismic site class and wind exposure of the specific parcel.

Foundation design is offered as a separate service so the right system can be selected for each site. Slab-on-grade is typical on stable, level lots; raised crawl-space on continuous stem walls is preferred on parcels with expansive clay or moisture concerns; pier-and-grade-beam systems are generally required on hillside lots, soft-soil regions, or where the geotechnical report calls for deeper bearing.

The plan's 19.83 ft ridge height exceeds California's standard 16-foot detached-ADU limit and the 18-foot transit-served / multifamily-zoned allowance. Several adaptations are available depending on your parcel: plan customization to lower the roof slope or revise the upper-floor elevation so the ridge fits the applicable height limit; configuration as an attached ADU where height matches the primary dwelling up to 25 feet; use as a small single-family residence in a zone permitting two-story construction; or permitting on parcels where local jurisdictional provisions allow greater height for detached secondary units. Plan customization is offered as an optional design service to adapt the plan to a specific parcel.

Available optional services: PE-stamped structural calculations, plan customization for site-specific adaptations (roof slope, elevation, interior layout), custom foundation design sized to the geotechnical report, structural observation visits during framing and finish, and permit support tailored to jurisdiction-specific requirements.