Architect vs Structural Engineer: Which Do You Need?

An architect and a structural engineer do two different jobs on the same building. Owners, developers and builders often use the terms loosely, yet each role carries its own legal obligations and its own professional registration. Knowing where one ends and the other begins helps a project run without expensive rework, and it tells you exactly who to call for the job in front of you.

What an Architect Does

An architect is responsible for the overall design of a building: how it looks, how spaces are arranged, how it will be used, and how it sits within its site and surroundings. Architects hold registration under the Architects Act 1991 (Victoria) and are legally required on many larger residential and commercial projects.

An architect develops the concept, produces planning and building permit drawings, coordinates the consultant team, and manages the aesthetic and functional intent of a project from first sketch through to completion. The architect leads the client relationship on design decisions and holds the vision for the finished building.

What a Structural Engineer Does

A structural engineer is responsible for making the building stand up safely under every load it will ever experience: gravity, wind, earthquake and occupancy among them. Structural engineers design the skeleton of a building, which includes footings, columns, beams, slabs, and load bearing wall assessment where walls are being removed, and they specify the materials, sizes, and connections that carry those loads safely to the ground.

In Victoria, structural engineering must be carried out by a Registered Professional Engineer of Victoria (RPEV) or an NER listed engineer. The structural engineer’s documentation forms part of the building permit application and is reviewed by the building surveyor before construction can begin.

Architect vs Structural Engineer: The Key Differences

The two roles cover different questions, use different documentation, and answer to different registration frameworks. The table below sets out who is responsible for what on a typical Melbourne project.

How Architects and Structural Engineers Work Together

Architects and structural engineers work together throughout a project rather than handing work to each other in a fixed sequence. The boundary between the two roles is collaborative rather than rigid. A structural engineer’s choice of column grid affects the architect’s floor plan. An architect’s decision to cantilever a balcony or open up a ground floor directly shapes the structural solution required. Bringing both disciplines in together from the start avoids the rework that comes from resolving structural constraints after the design is already set.

Do You Need Both an Architect and a Structural Engineer?

For most new builds and major additions, yes. The architect leads the design and the structural engineer provides the structural documentation required for the building permit. On smaller projects, particularly single storey extensions or minor alterations, a structural engineer is often engaged directly with no architect, but this depends on the scope and the council requirements.

A structural engineer is required regardless of whether an architect is involved for work such as the following:

• Removing or modifying a load bearing wall to open up a living area
• Adding a storey or upper floor to an existing building
• Installing a mezzanine floor
• Building a retaining wall over 1.0 m in height
• Underpinning or strengthening existing footings
• Any new footing design in Melbourne’s reactive clay soils
• A structural assessment of a property showing cracking or movement

For any of these, a structural design package or a set of structural engineer inspections from a registered engineer forms part of the building permit process, with or without an architect.

Do You Need an Architect or a Structural Engineer for an Extension or Wall Removal?

This is the question most Melbourne homeowners actually arrive with. The answer depends on how much the design is changing, not just on the size of the job.

For a single storey extension or a straightforward internal alteration, many homeowners work with a building designer or draftsperson for the plans and engage a structural engineer directly for the footings, beams and framing. An architect is not always required at this scale. For a load bearing wall removal, no architect is needed at all: a structural engineer assesses the wall, designs the beam that replaces it, and provides the documentation the building surveyor requires.

For a larger second storey addition, a substantial reconfiguration, or a design led renovation where appearance and spatial flow are central, an architect leads and a structural engineer joins the consultant team. The more the building form is changing, the earlier the architect earns their place.

Who Do You Hire First?

For new builds and major additions, the architect typically leads and brings the structural engineer in as part of the consultant team. For targeted structural work, the structural engineer is engaged directly. The four stages below show how the two roles interlock on a design led project.

How the Two Are Engaged Together

Where both are required, the usual arrangement is that the client engages the architect, and the architect either engages the structural engineer as a subconsultant or nominates one for the client to engage directly. Direct engagement of the engineer by the client is common on residential projects because it keeps the structural fee and the structural scope visible to the person paying for it. Structural engineering is generally charged either as a fixed fee for a defined package or against an hourly rate, which across the profession typically sits in the range of $150 to $300 per hour depending on seniority and complexity.

Whichever route is used, three things determine how well the architect and engineer work together:

• The engineer is brought in at concept stage rather than after the design is fixed, so structural constraints shape the plan instead of breaking it
• The architectural brief is stable before structural documentation starts, because every change to the layout moves the load path
• Site and soil information is available early, since the footing system depends on the site classification and drives a large part of the structural design

Working With Principal Built Engineering

Principal Built Engineering works alongside architects, builders, and directly with owners across Melbourne on residential extensions, townhouse developments, commercial fit-outs, and multi-storey projects. For projects without an architect, PBE can be engaged directly for structural design and documentation, and for targeted problems such as a wall removal, a mezzanine, or cracking in an existing building. The starting point is always understanding what the project actually needs.

Frequently Asked Questions