The Short Answer
Structural engineering is a specialized branch of civil engineering. A civil engineer works on the broad infrastructure that supports a site — grading, drainage, roads, utilities, and site development. A structural engineer focuses specifically on the load-carrying system that keeps a building or structure standing up under gravity, wind, and seismic forces. Most building projects need structural engineering; projects that involve site development, earthwork, or public infrastructure also need civil engineering. Many are handled by different specialists working together.
What a Civil Engineer Does
Civil engineering is a broad discipline covering the design of infrastructure and site systems. On a typical building project, the civil engineer is responsible for what happens on the ground and outside the building footprint.
- Site grading and earthwork to establish finished elevations and manage runoff.
- Stormwater management, detention, and drainage design.
- Site utilities — water, sewer, and storm connections to public mains.
- Paving, parking layouts, driveways, and access.
- Erosion control and permitting related to site development.
Civil engineering also encompasses public works — roads, bridges, dams, and municipal infrastructure — which is a distinct practice area from private site development.
What a Structural Engineer Does
A structural engineer designs and verifies the elements that carry loads: foundations, framing, connections, and the lateral system that resists wind and earthquakes. The structural engineer produces stamped drawings and calculations documenting member sizes, materials, and configurations. Their professional responsibility is the safety and code compliance of the structure itself. For Apex Grid work, the responsible individual's current license, firm authorization, discipline, and AHJ requirements are verified before any structural seal or stamp.
Where the Two Overlap
The disciplines meet at the foundation and the soil. Foundation design depends on soil bearing capacity, which is typically defined by a geotechnical engineer (a specialized civil branch) and used by the structural engineer to size footings. Retaining walls are a classic shared item — the civil engineer sets the grades and the wall location while the structural engineer designs the wall to resist soil pressure. Coordination between the two prevents conflicts between site elevations and structural details.
When It Applies
You need a structural engineer when your project affects the building's load path: new construction, additions, wall removals, equipment loads, or structural distress. You need a civil engineer when your project involves the site: new footprints that change drainage, new parking, grading, or utility connections. Small interior remodels often need only structural input, while ground-up construction on a raw site usually needs both. As a multi-discipline firm, we can provide structural and civil engineering together and coordinate them internally.
Frequently Asked Questions
Is a structural engineer also a civil engineer?
Structural engineering is a specialty within civil engineering, and many structural engineers hold civil PE licenses. However, day-to-day structural design requires focused expertise that a general civil practice may not provide.
Can one firm handle both?
Yes. Multi-discipline firms like ours coordinate structural, civil, and geotechnical work under one roof, which reduces handoffs and keeps site grades and foundations aligned.
Who designs my building's foundation?
The structural engineer designs the foundation, using soil parameters from a geotechnical report. If earthwork or drainage changes around the foundation, the civil engineer coordinates those grades.