Yuna Drafting
Why do so many Bay Area permit applications come back with structural-energy coordination corrections — and what stops them? The answer is almost always whether the applicant submitted a coordinated structural Title 24 combo package Bay Area plan checkers can review as a unified set. Most projects that require structural engineering also require a Title 24 energy report, and the two documents must reference the same building envelope assumptions or they will conflict. Our team at Yuna Drafting assembles these packages for additions, ADUs, and garage conversions across San Jose, Sunnyvale, Cupertino, and the surrounding county — and this post explains what the package contains, when projects need one, and how to get through plan check without a correction cycle.
The phrase "combo package" is industry shorthand for a coordinated submittal pairing wet-stamped structural engineering documents with a compliant California Title 24 Part 6 energy compliance report. It is not an official building code designation. What makes it meaningful is coordination: the structural engineer's wall assembly specs, insulation depths, and roof framing feed directly into the energy model, and both documents must reflect the same assumptions before plan check will accept them. When they do not match, the project receives a correction notice — and in Santa Clara County, that notice adds weeks to the timeline.
Bay Area building departments — particularly San Jose, Sunnyvale, and Cupertino — have tightened plan check review criteria across successive code cycles. Reviewers are trained to compare insulation R-values between the structural assembly schedule and the CF1R input. Discrepancies that might have passed through a decade ago now reliably generate first-round corrections. Submitting a coordinated combo package is no longer optional for any project that triggers both structural and energy review.
Contents
- Project Types That Require a Structural Title 24 Combo Package Bay Area
- What a Structural Title 24 Combo Package Actually Contains
- How Our Team Coordinates the Two Packages From Intake to Submittal
- Cost and Timeline: Combo vs. Separate Submittals
- Best Practices for Getting a Combo Package Through Plan Check
- Immediate Benefits of Bundling Structural and Title 24 Work
- Frequently Asked Questions
Project Types That Require a Structural Title 24 Combo Package Bay Area
Room Additions and Second-Story Work
Any project that adds conditioned square footage and involves new or modified structural elements lands in combo package territory. Permit offices apply different square footage thresholds, but our team consistently sees these project types requiring both structural calcs and a Title 24 report:
- Room additions over roughly 500 sq ft (threshold varies by jurisdiction)
- Second-story additions and pop-top conversions
- Projects removing or relocating load-bearing walls
- Additions that penetrate the existing thermal envelope
- Any new conditioned space requiring its own foundation
- Accessory dwelling units with significant structural modifications
The second-story addition workflow in San Jose makes this dynamic concrete: roof structure, insulation assembly, and thermal envelope are inseparable design decisions. Structural and energy consultants who do not coordinate leave those decisions in conflict — and plan checkers flag it every time.
ADU and Garage Conversion Projects
ADUs are the highest-volume project type our team processes for combo packages. A detached ADU needs a full permit set, and in most Bay Area jurisdictions that means structural calcs plus a coordinated Title 24 report. Garage conversions follow the same pattern: the existing slab, shear walls, and roof framing all need engineering review, and the new conditioned space must meet Part 6 energy requirements using assumptions that match the structural drawings.
For ADU-specific energy compliance expectations, our post on Title 24 energy calculations for ADUs in Santa Clara County covers what plan checkers look for and how the energy model handles existing versus new construction assemblies.
Our team's intake rule: if a project touches the structural system and adds conditioned space, assume a combo package is required. Confirming this at intake takes minutes; discovering the gap at plan check costs weeks.
What a Structural Title 24 Combo Package Actually Contains
The Structural Engineering Component
The structural side is a complete engineering deliverable. It includes:
- Foundation plan with footing schedules and assumed soil bearing values
- Floor and roof framing plans with member sizes called out
- Shear wall schedule and hold-down locations
- Gravity and lateral load calculations demonstrating compliance under CBC and ASCE 7
- Connection details and nailing schedules
- Wet stamp and signature from a California-licensed structural engineer (PE)
Bay Area seismic exposure — Seismic Design Category D across most of Santa Clara County — drives the lateral analysis. Hold-down hardware, shear wall nailing patterns, and diaphragm design are primary deliverables, not secondary considerations. Plan checkers verify them against the architectural drawings in the same submittal.
The Title 24 Energy Compliance Component
The energy side includes:
- CF1R compliance form — the primary document plan checkers review
- Prescriptive or performance path compliance documentation
- Envelope inputs: insulation R-values, window U-factors, SHGC, infiltration assumptions
- Mechanical, lighting, and water heating compliance scoped to the project
- HERS verification requirements listed by measure
- Cross-reference notes citing the structural drawing set by sheet number
The structural engineer specifies the wall and roof assembly — material, framing depth, insulation type. The Title 24 report pulls those same assemblies into the energy model. If the structural drawings are revised after the CF1R is issued, the energy report must be revised to match. Our team builds this dependency into the production workflow explicitly.
| Project Type | Structural Calcs Required | Title 24 Required | Combo Package Recommended |
|---|---|---|---|
| Detached ADU (new construction) | Yes | Yes | Yes |
| Second-story addition | Yes | Yes | Yes |
| Room addition (> 500 sq ft) | Yes | Yes | Yes |
| Garage conversion to ADU | Yes | Yes | Yes |
| Room addition (< 500 sq ft, no shear work) | Sometimes | Yes | If structural is triggered |
| Junior ADU (no structural changes) | Rarely | Yes | Rarely needed |
| Kitchen/bath remodel (no structural) | No | Varies by scope | No |
How Our Team Coordinates the Two Packages From Intake to Submittal
Step 1 — Scope Confirmation and Jurisdiction Check
Before drafting begins, our team confirms project scope against the applicable jurisdiction's plan check checklist. We identify:
- Which structural elements are new versus existing-and-verified
- Whether prescriptive or performance Title 24 compliance applies
- HERS rater measures triggered by the project scope
- Jurisdiction supplements — Santa Clara County publishes its own requirements beyond state minimums, and individual cities add further layers
Step 2 — Structural Engineering First Pass
Structural engineering drives the envelope. Wall depths, roof rafter sizes, and foundation type all constrain what the energy model can assume. Our team completes the structural first pass before drafting the Title 24 report — not in parallel. This sequence eliminates the most common coordination error: a CF1R built on assumed 2×6 walls when the structural engineer specifies 2×4.
Step 3 — Title 24 Modeling Against Confirmed Structural Assumptions
With framing confirmed, the energy analyst runs the Title 24 model using:
- Window placements from the architectural drawings
- Wall assembly depths and insulation types from the structural set
- Mechanical equipment specifications from the project scope
- Climate zone confirmed for the specific project address
The CF1R is generated, HERS measures are tagged by type, and the report is cross-referenced to the structural sheet numbers before it leaves our office.
Step 4 — Internal Coordination Review
Before submittal, our team runs a four-point conflict check:
- Insulation R-values match between the structural assembly schedule and the Title 24 CF1R inputs
- Window U-factors listed in the CF1R align with header sizing assumptions in the structural drawings
- Mechanical equipment referenced in Title 24 appears consistently on the permit drawings
- The PE stamp and the CF1R share the same project address and legal description
Step 5 — Package Assembly and Submittal
The final package goes to plan check as a unified submittal: structural calculations, framing plans, Title 24 CF1R, and the full architectural permit set — all uploaded or counter-submitted together. Our team labels documents consistently so reviewers can cross-reference without searching across separate uploads.
Submittal tip: a one-page coordination summary at the front of the package — listing which Title 24 report version each structural drawing was coordinated with — takes five minutes to prepare and eliminates the most common first-round reviewer question.
Cost and Timeline: Combo vs. Separate Submittals
What a Combo Package Typically Costs
Pricing scales with project complexity. A solo structural engineer and a solo energy consultant working independently each deliver a package — but those packages may conflict. Resolving conflicts in plan check costs real money: correction fees, revised calculations, re-review time, and delayed permit issuance. In our experience, that downstream cost routinely exceeds whatever coordination premium a single-provider combo package carries.
| Package Component | Separate Providers (Est. Range) | Coordinated Combo (Est. Range) | Correction Risk |
|---|---|---|---|
| Structural calcs only | $1,500 – $4,500 | — | Moderate if Title 24 is uncoordinated |
| Title 24 report only | $400 – $900 | — | Moderate if structural is uncoordinated |
| Both, uncoordinated | $1,900 – $5,400 | — | High — correction cycles likely |
| Coordinated combo package | — | $2,200 – $5,800 | Low — first-pass submittal |
| Per plan check correction cycle | $300 – $1,500+ (jurisdiction fees + consultant revision time) | Avoided with coordination | |
Where Combo Packages Deliver Time Savings
Plan check timelines in Santa Clara County currently run 6–10 weeks for projects that cannot go over the counter. A single correction cycle adds 3–5 weeks. Our team's project history demonstrates that coordinated combo packages clear plan check on the first submission at a materially higher rate than uncoordinated submittals.
The compounding effect is real. Contractors start immediately after permit issuance. Homeowners stop carrying costs on a stalled project. A first-pass approval is not just a procedural outcome — it has direct financial value that scales with project cost and local carrying expenses.
Best Practices for Getting a Combo Package Through Plan Check
Submit Coordination Notes on Both Documents
The structural drawings should note which Title 24 report version they were coordinated with. The CF1R should cite which structural drawing set it references. This bidirectional cross-reference takes minutes to add and signals to reviewers that both consultants worked from the same assumptions — which is exactly the assurance they are looking for before approving a first-round submittal.
Lock the Envelope Assumptions Early
Wall assembly type, insulation strategy, and window-to-wall ratio are the three shared assumptions that both disciplines depend on. Changing any of them mid-process forces simultaneous revisions to both packages. Our team's standard practice is to finalize envelope decisions before either the structural or energy work goes into production. Projects that skip this step are the ones that generate mismatched R-values at plan check.
Most Bay Area building departments will not accept a Title 24 report referencing a window type not shown on the structural or architectural drawings. Early envelope lock removes the most common source of mid-production rework and prevents revision cycles that push submittal dates back by weeks.
Know the Jurisdiction's HERS Requirements
HERS III verification requirements vary by jurisdiction and project scope. Some Santa Clara County cities require duct leakage testing even when HVAC is not the primary scope of work. Our team tracks these requirements at intake — before the energy report is drafted — so HERS measures are never discovered late and never delay contractor scheduling after permit issuance.
Immediate Benefits of Bundling Structural and Title 24 Work
Fewer Plan Check Corrections
The measurable, immediate benefit of a coordinated combo package is a lower correction rate. Reviewers at Santa Clara County DSA and San Jose Building Division flag structural-energy mismatches consistently. A package that eliminates those conflicts before submittal simply clears faster. Our team treats this as the baseline expectation, not an aspirational goal.
One Point of Contact for Permit Questions
When a structural engineer and Title 24 consultant are different firms, plan check questions create a coordination loop. The city asks the architect; the architect routes questions to both consultants; the consultants answer independently, sometimes inconsistently. With a single coordinated package, our team fields all technical questions directly — and the answers are consistent because the documents were built to be consistent from the start.
Cleaner Handoff to the Contractor
A coordinated combo package gives the contractor one set of documents where the insulation schedule, framing specs, and energy compliance measures all point in the same direction. There is no reconciling a structural package that specifies R-38 attic insulation against a CF1R that modeled R-30. Contractors who build from coordinated documents have fewer RFIs, tighter bids, and fewer field corrections. That efficiency starts with the permit package, not on the job site.
Frequently Asked Questions
A structural Title 24 combo package is a coordinated permit submittal that pairs wet-stamped structural engineering calculations with a California Title 24 Part 6 energy compliance report, prepared so both documents reference the same building envelope assumptions. Not every permit application requires one — projects with no structural engineering component, such as interior remodels that do not touch load-bearing elements, may need only a Title 24 report. However, any project that adds conditioned space and triggers structural review — including room additions over roughly 500 square feet, second-story work, detached ADUs, and garage conversions — will require both, and submitting them as a coordinated set is the most reliable way to avoid plan check corrections in Bay Area jurisdictions.
Preparation time depends on project complexity and how quickly the building envelope assumptions can be finalized. For a standard room addition or detached ADU in Santa Clara County, our team typically delivers a coordinated combo package within two to four weeks from intake, assuming architectural drawings are complete and mechanical equipment specs are available. Projects with unusual foundation conditions, hillside sites, or deferred submittals take longer. Compressing the coordination step to meet an arbitrary internal deadline is the fastest way to produce documents with internal conflicts — and conflicts at plan check cost more time than the coordination step ever would.
It is possible, but it requires explicit, documented coordination between the two firms — and in our experience, that coordination rarely happens organically when consultants work independently. The structural engineer specifies wall assemblies; the energy consultant needs those specifications to build an accurate energy model. When the structural engineer delivers calcs without sharing assembly details, the CF1R gets built on assumed values that may not match the permitted drawings. Plan check reviewers in San Jose and Santa Clara County are specifically trained to compare these values. Mismatches generate corrections. A single-provider combo package eliminates the coordination gap by design, which is why our team recommends it for every project where both deliverables are required.
A structural Title 24 combo package is not a premium service — it is the minimum viable submittal for any Bay Area project where the structural system and the thermal envelope share the same walls.
