ADU Structural Engineering Services

Get Permit-Ready ADU Structural & Civil Engineering Plans

California structural & civil engineers specializing in Junior ADUs (JADUs), delivering code-compliant structural and civil engineering plans for JADU conversions within existing single-family residences throughout California. Typical turnaround for structural & civil plan sets is 2-3 weeks. Unlimited plan-check revisions within our engineering scope(1) at no extra cost.

Licensed CA Engineers
Same-Day Quote
2-3 Weeks Delivery
Highly Responsive
Permit Guarantee(1)
Fixed Transparent Pricing
Licensed California Engineers|CA PE License #68517 - Amarendra Prasad, PE
3000+
Projects Completed
2-3 Weeks
Average Delivery
Guaranteed(1)
Permit Approval
4.8
Google & Yelp Rating

Build your junior ADU with confidence. We engineer JADU conversions within your existing home—evaluating structural capacity, designing modifications for unit separation, and addressing seismic loads and California building code requirements—delivering permit-ready PE-stamped plans for your property.

Junior ADU (JADU) Requirements by County & Key Engineering Considerations

  • Junior ADU Structural Design
    Structurally optimized junior ADU engineering addressing existing-home constraints, spatial limitations, and California code compliance. We analyze load-bearing walls, design opening headers and separation elements, and engineer efficient layouts that maximize the 500 sq ft allowance while maintaining full structural code compliance.
  • Permit-Ready Plan Sets
    PE-stamped structural and civil engineering plans designed for fast approvals. We deliver clean, complete plan sets with all required calculations and documentation—and respond to every plan-check comment so your project moves through review without delays.
  • Project Engineering Coordination
    We coordinate structural, civil, grading, and drainage engineering alongside consultant coordination and permit response support for your junior ADU project. Our integrated approach unifies every engineering discipline into one streamlined plan set—eliminating gaps between consultants and ensuring smooth approvals.
  • County-Specific Structural Standards
    Structural design criteria, seismic requirements, and permitting workflows vary across California counties. We provide jurisdiction-specific engineering solutions tailored to local building department requirements for this ADU type.
Select Your County

Serving all 58 California counties with expert Junior ADU (JADU) structural engineering.

How ProStruct Helps

  • PE-stamped structural plans ready for permit submission
  • Foundation design, framing plans, and lateral system engineering
  • Structural calculations that meet California building code
  • Coordination with your architect and contractor
  • Unlimited plan-check revisions within engineering scope
  • Dedicated project manager — no extra cost
HOW IT WORKS

Fast, Easy & Convenient Process

1

Request a Free ADU Consultation

Share a few project details and our engineering team will review your scope and guide you through permitting and design next steps.

2

Get Same-Day Quote

After reviewing your project details, we'll provide a transparent quote the same day--typically within a few hours. Pricing varies based on project scope, complexity, and requirements.

3

Receive Permit-Ready Plans in 2-3 Weeks

We deliver complete structural permit sets. *If building departments have comments related to our scope, we handle all revisions--no extra fees, no limits.

SUCCESS STORIES

What Our Clients Are Saying

See why homeowners and industry professionals trust us with their projects.

Trusted by homeowners and AEC industry professionals

Fast delivery • Permit guarantee(1) • Fixed Transparent Pricing

COMMON QUESTIONS

Frequently Asked Questions

A Junior ADU (JADU) is an accessory dwelling unit created within an existing single-family residence, typically converting a portion of the primary dwelling into a separate dwelling unit. JADUs share the same foundation and structural systems as the primary residence, requiring structural evaluation of existing framing and load paths to ensure they meet code requirements for the new use. California building codes require PE-stamped structural plans for all JADU projects to verify structural capacity and compliance.

JADU structural & civil engineering costs in California vary based on project size, complexity, existing structure condition, and the extent of structural modifications required. Our pricing includes structural evaluation of existing structure, structural calculations, load path analysis, structural modification design, separation wall design, framing plans, lateral system design, civil engineering coordination, and PE-stamped permit-ready structural & civil engineering plans. We provide same-day quotes with transparent, fixed pricing--no hidden fees or surprises. Contact us for a free quote specific to your JADU project.

Yes, California requires PE-stamped structural plans for all JADU projects. Structural engineering is mandatory for structural evaluation of existing structure, load path analysis, structural modifications, separation design, lateral force-resisting systems, and seismic safety compliance with California building codes. JADUs require structural evaluation of the existing primary residence to ensure it can accommodate the modifications needed for the new use.

Typical turnaround for structural & civil plan sets for JADU projects in California is 2-3 weeks. This includes site evaluation, structural evaluation of existing structure, structural calculations, load path analysis, structural modification design, separation wall design, framing plans, lateral system design, civil engineering coordination, and complete plan sets. Rush services available for urgent projects.

JADU conversions require structural evaluation of existing framing and load paths within the primary residence. Key considerations include existing framing system evaluation, load path analysis, structural modifications needed for separation, seismic considerations for modifications within the primary dwelling, and ensuring the existing structure can accommodate the new use. We provide structural engineering services including existing structure evaluation, load path analysis, structural modification design, separation wall design, and lateral force-resisting system design specific to JADU conversions within existing residences.

Under California ADU law, JADUs can be up to 500 square feet and must be created within the existing single-family residence. JADUs share the same foundation and structural systems as the primary residence. Specific limits may vary by local jurisdiction. Our structural engineering services accommodate JADUs within these size parameters, providing complete structural analysis and design that accounts for existing structure capacity and required structural modifications.

No, JADUs typically share the same foundation as the primary residence since they are created within the existing single-family dwelling. However, structural evaluation is required to verify foundation capacity under new loads. We provide structural analysis and foundation capacity evaluation for JADUs, including load-bearing capacity calculations, foundation structural assessment, and verification that existing foundations can accommodate the modifications in compliance with California building codes. Foundation capacity must account for existing loads, new JADU loads, seismic loads, and soil characteristics specific to the project site.

JADU projects may require civil engineering services including site coordination, grading design, and drainage design. We provide high-level civil engineering coordination for JADU projects, ensuring proper site layout, drainage considerations, and grading requirements are addressed in coordination with structural design. Civil engineering services are provided at a high level and coordinated with structural plans.

California cities and counties use various permitting systems--some online, some in-person. We provide complete PE-stamped structural & civil engineering plan sets in PDF format ready for submission. Our plans include all required structural and civil engineering sheets, calculations, existing structure evaluation, and documentation needed for plan check. We also respond to all building department comments throughout the review process.

Yes, we offer construction administration services for JADU projects including: responding to contractor RFIs, reviewing shop drawings and submittals, site visits for structural observations, and certification letters. This ensures your JADU is built according to structural plans and code requirements.

Start your structural and civil engineering project

Ready to Start Your Project?

Get a free, no-obligation quote within 24 hours. Our experienced structural and civil engineers are ready to help with your residential or commercial project.

Free Quote in 24 Hours
2-3 Week Delivery
Permit Guarantee(1)
Call (844) 750-0773

Trusted by 3,000+ homeowners and AEC professionals • Licensed in California State • 35+ years experience