Structural Engineering Questions — Answered

What does a structural engineer do?

A structural engineer designs the load-bearing system of a building — the beams, columns, shear walls, and foundation that keep it standing under gravity, wind, and seismic forces. We translate your architectural design into a structure that will perform safely for the life of the building, can be built by a contractor, and will be approved by the building department.

Do I need a structural engineer or an architect?

You need both for most new construction projects. Your architect designs how the building looks and functions — the floor plan, elevations, and interior layout. Your structural engineer designs how it stands up. The structural drawings are part of the permit package alongside the architectural drawings. One cannot substitute for the other.

What is the difference between a PE and an SE?

A Professional Engineer (PE) licensed in structural engineering can stamp structural drawings in most states. A Structural Engineer (SE) is a separate license in states like California and Washington that requires additional examination beyond the PE. SE licensing is required for hospitals, schools, and essential facilities in those states. For most residential projects, a PE with structural experience is required — LPL provides PE/SE oversight on all projects.

What information do you need to provide a quote?

To provide a fee proposal, we typically need: the project address, architectural plans (even schematic-level is fine at the quote stage), the project type (custom home, ADU, multifamily, etc.), and the building department you’ll be submitting to. If you have a geotechnical report, share that too — it affects foundation scope.

How much does structural engineering cost for a custom home in California?

Structural engineering fees for a California custom home typically range from $8,000 to $25,000 depending on square footage, site complexity (flat vs. hillside), number of plan check cycles anticipated, and whether a geotechnical report is provided. LPL provides itemized proposals so you know exactly what’s included.

How much does structural engineering cost for an ADU?

A straightforward detached ADU structural package typically ranges from $3,000 to $7,000. Attached ADUs, second-story ADUs, and garage conversions that require existing structure evaluation are typically $4,000 to $10,000. Site complexity, state, and building department requirements affect cost.

How much does multifamily structural engineering cost?

Multifamily structural fees scale with project size and complexity. A duplex or small triplex may start around $10,000–$15,000. A 20-unit wood-frame apartment building typically ranges from $40,000 to $80,000+. Podium structures, post-tensioned concrete, and mid-rise steel are priced on a project-specific basis. LPL provides proposals with clear scope and no surprise add-ons.

Do you charge for plan check response?

LPL’s proposals include a defined number of plan check response rounds — typically one or two. Additional rounds beyond what’s included are billed at our hourly rate. We’ll tell you what’s included upfront, and we work hard to minimize plan check comments through thorough initial submittals.

How long does structural engineering take?

Typical timelines from project kickoff to permit-ready drawings: ADU (simple): 2–3 weeks. Custom home: 3–5 weeks. Multifamily (small): 4–6 weeks. Multifamily (mid-rise or complex): 8–14 weeks. Hillside projects: add 1–2 weeks for geotechnical coordination. These assume architectural plans are complete when we start. Incomplete architectural plans at kickoff extend structural timelines.

Can you fast-track a structural package?

Yes, in some cases. If your project has standard conditions (flat site, typical foundation, no unusual structural features), we can prioritize it in our schedule for an expedite fee. Contact us to discuss your timeline needs and we’ll tell you honestly what’s achievable.

How does the structural engineering process work from start to finish?

After you send us architectural plans and a signed proposal, here’s the typical flow: (1) Kickoff — we review plans, identify structural questions, and confirm scope. (2) Preliminary coordination — we send the architect marked-up questions and confirm structural element locations. (3) Calculations and drafting — we produce the engineering analysis and structural drawings. (4) QC review — PE/SE of record reviews and stamps drawings. (5) Delivery — you receive permit-ready PDF drawings and calculation package. (6) Plan check response — we respond to building department structural comments as they come in.

Do you work with my architect directly?

Yes, and we prefer it. Early coordination between structural and architectural design avoids expensive late-stage conflicts. We communicate directly with your architect on structural element locations, beam depths, shear wall positions, and anything that affects the architectural design. You’re kept in the loop on all significant decisions.

What CAD formats do you work in?

We produce drawings in AutoCAD and deliver in PDF for permit submittal. We can receive architectural plans in PDF, AutoCAD, or Revit format. For Revit projects, we coordinate with the architect on the level of BIM coordination required.

What states is LPL Consultants licensed in?

LPL Consultants holds active engineering licenses in California, Texas, Florida, and Washington. Every project in each state is stamped by the licensed engineer of record for that state.

Can LPL work on projects in states you’re not currently licensed in?

Our current active licenses are in CA, TX, FL, and WA. If you have a project in another state, contact us — reciprocal licensing may be available for your state depending on the project timeline.

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