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ADU Structural Engineering

Specialized structural engineering for Accessory Dwelling Units (ADUs) including detached units, garage conversions, and attached ADUs throughout California.

What is ADU Engineering?

ADU structural engineering requires expertise in California ADU regulations, residential construction, and creative design within constrained spaces. Our engineers maximize your ADU investment with efficient, cost-effective structural solutions.

Key Benefits

Why Choose Our ADU Engineering Services

ADU regulatory expertise across California jurisdictions

Fast-track processing for streamlined ADU approvals

Cost-effective designs optimized for ADU budgets

Garage conversion and detached ADU specialization

Coordination with ADU-experienced architects

Foundation solutions for challenging sites

PE-stamped plans ready for permit submittal

Deliverables

What We Provide

Comprehensive adu engineering services with complete documentation

ADU Structural Design

Complete structural engineering for new detached ADUs, garage conversions, and attached ADU additions.

Foundation Engineering

Foundation design for ADUs including slab-on-grade, raised foundations, and pier foundations.

Framing Plans

Wood-frame structural plans optimized for ADU construction and budget constraints.

Seismic Design

Lateral force-resisting system design meeting California seismic requirements for residential structures.

Garage Conversion Plans

Structural modifications for converting existing garages to ADUs including new openings and improvements.

Permit-Ready Documents

PE-stamped structural plans and calculations prepared specifically for ADU permit requirements.

Our Process

How It Works

Our streamlined process for adu engineering

1

ADU Consultation

Free consultation to discuss ADU type, review site, and provide guidance on structural approach and costs.

2

Proposal & Agreement

Clear proposal with ADU-specific scope, deliverables, fees, and realistic timeline.

3

Site Analysis

Review of site conditions, setbacks, utilities, and structural constraints for ADU placement.

4

Structural Design

Engineering design of ADU structure optimized for cost and constructability.

5

Drawing Preparation

Production of ADU structural plans, details, and schedules.

6

PE Stamping

Professional Engineer review, calculations, and stamping for permit submittal.

7

ADU Permit Support

Support through ADU expedited review process and response to any corrections.

8

Construction Guidance

Available for questions and clarifications during ADU construction.

Common Applications

We provide adu engineering for a wide range of projects

Detached ADUs (new construction)
Garage conversions to ADUs
Attached ADUs and additions
Junior ADUs (JADUs)
Above-garage ADUs
ADU second story additions
Prefab and modular ADU support
ADU foundation design
ADU structural modifications

Cost Information

Transparent pricing for your project

Typical Range:

$2,000 - $5,000 for most ADUs

Factors Affecting Cost:

  • ADU size (under 750 sq ft vs. larger)
  • New construction vs. conversion
  • Foundation type and site conditions
  • Number of floors
  • Structural complexity
  • Timeline requirements

ADU structural engineering is typically priced as fixed-fee based on ADU size and complexity.

Timeline

What to expect for your project

Design Phase

1-2 weeks for typical ADUs

Permitting

2-4 weeks (ADUs get expedited review)

Total Timeline

3-6 weeks from start to permit

Timelines vary based on project complexity, jurisdiction requirements, and information availability. We provide detailed schedules during consultation.

Frequently Asked Questions

Common questions about adu engineering

Do I need structural engineering for my ADU?

Yes, all ADUs require PE-stamped structural plans for permit approval. This includes new detached ADUs, garage conversions, and attached ADUs. Structural plans ensure your ADU is safe and meets building codes.

How much does ADU structural engineering cost?

Most ADUs cost $2,000-$5,000 for structural engineering. Small ADUs under 500 sq ft may be $2,000-$3,000, while larger or complex ADUs may be $4,000-$6,000. Garage conversions are typically $2,500-$4,000.

How long does ADU structural design take?

Most ADUs take 1-2 weeks for design and drawing production. ADUs benefit from expedited plan review, typically 2-4 weeks. Total timeline from start to approved permits is usually 3-6 weeks.

Can you work with ADU builders and prefab companies?

Yes! We regularly work with ADU-specialized builders, general contractors, and prefab ADU companies. We can adapt our designs to work with prefab systems or provide custom engineering for site-built ADUs.

Ready to Build Your ADU?

Get a free consultation for your ADU project. Our ADU-specialized structural engineers will help you navigate the process and provide cost-effective structural design for your accessory dwelling unit.