What Does a Structural Engineer Do
(and Do You Need One)?
A structural engineer analyses, designs, and assesses the structural elements of buildings and other structures, the parts that carry loads: floors, beams, columns, walls, and foundations. They ensure that a structure is safe, stable, and fit for its intended use. In Ireland, a Chartered Structural Engineer (a member of Engineers Ireland) provides the certified structural design, reports, and inspections required for building control, planning permission, mortgage lending, and insurance purposes.
The structural engineer's fundamental task is to make structures safe. This guide walks through what that involves in practice, how the discipline differs from civil engineering, when you need one, and what the process looks like from first contact to sign off.
What a Structural Engineer Does: The Core Role
This involves calculating the loads that a structure must carry, including its own weight, the weight of people, furniture, equipment, snow, wind, and dynamic forces, and designing or assessing the structural elements to carry those loads without failure.
In practice, structural engineering work falls into two broad categories: design work and assessment work.
Design Work
For new buildings, extensions, or significant alterations, the structural engineer designs the structural system:
- Foundation design: determining the type and depth of foundations required to transfer loads from the structure to stable ground
- Floor and beam design: calculating the size and specification of structural beams, columns, floor joists, and slabs
- Structural drawings: producing the drawings that contractors use to build the structure and that building control requires for compliance
- Specification: defining the materials, grades, and construction methods for structural elements
- Building control certification: inspecting completed works and certifying compliance with the design
Assessment Work
For existing buildings, the structural engineer assesses what is there and whether it is adequate:
- Pre-purchase structural surveys: assessing the structural condition of a building before it is bought
- Subsidence and crack investigations: determining the cause and extent of structural movement
- Structural reports for planning or mortgage: providing a certified assessment of existing structural condition
- Defect investigations: identifying the structural cause of a problem, such as a sagging floor, a cracked wall, or a failing roof, and specifying the remedy
- Load assessment: checking whether an existing structure can carry a new or increased load, for example a proposed loft conversion or a new piece of heavy equipment
Is a Structural Engineer the Same as a Civil Engineer?
Structural and civil engineering are related but distinct disciplines. The terms are often confused, partly because many engineers hold expertise in both, and partly because in Ireland the title 'Chartered Engineer' covers both disciplines under Engineers Ireland.
| Structural Engineering | Civil Engineering | |
|---|---|---|
| Primary focus | Buildings and structures: what they are made of and how they carry loads | Infrastructure and the ground: roads, drainage, earthworks, utilities |
| Typical outputs | Structural drawings, reports, beam schedules, foundation designs | Drainage designs, road designs, flood risk assessments, civil infrastructure reports |
| Typical clients | Homeowners, architects, developers (building focused) | Developers, local authorities, contractors (site and infrastructure focused) |
| When you need them | Extension design, structural surveys, subsidence investigations, building defects | Site development, drainage design, roads, flood risk, retaining walls |
When Do You Need a Structural Engineer?
- Buying a Property If you are buying a house or commercial property that has visible cracking, has been extended, has an unusual structure, or is of older construction (pre-1960), a structural survey by a Chartered Structural Engineer adds a layer of assurance that a general property surveyor cannot provide. The structural engineer assesses whether cracks are cosmetic or structural, whether extensions are properly built, and whether there are any structural issues that should affect the purchase price or completion.
- Planning a House Extension Most house extensions in Ireland require a structural engineer for planning and building control. The planning application may require structural drawings or a structural statement; building control (BCMS) requires a Chartered Engineer to inspect works stages and certify compliance on completion.
- Suspected Subsidence or Structural Damage If your property has diagonal cracking, sticking doors or windows, sloping floors, or other signs of structural movement, you need a Chartered Structural Engineer, not a builder, surveyor, or contractor, to investigate and determine the cause. Only a Chartered Structural Engineer's report is accepted by insurers, mortgage lenders, and courts as a definitive professional assessment.
- Loft Conversion or Internal Alteration Converting a loft to habitable space, removing an internal wall, or installing a beam to create an open plan space all require structural engineering input, to assess whether the existing structure can accommodate the change, and to design any new structural elements required.
- Mortgage or Planning Requirement Mortgage lenders, planning authorities, and building control all have circumstances where they require a Chartered Structural Engineer's input. If your solicitor, mortgage provider, or planning authority has asked for an engineer's report, you need a Chartered Structural Engineer: the engineering qualification is a statutory requirement in most of these contexts.
What Happens When You Engage a Structural Engineer?
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1
Brief and Scope You explain what you need, whether that is a survey, a design, or an investigation, and the engineer confirms the scope, fee, and programme.
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2
Site Visit The engineer visits the property to inspect, measure, and gather the information needed.
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3
Analysis The engineer performs the calculations, assessments, or investigations required.
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4
Report or Drawings The engineer produces the deliverable: a structural survey report, a set of structural drawings, or an assessment report.
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5
Follow Up Depending on the scope, the engineer may carry out further site visits during construction (building control), monitoring visits (subsidence), or issue certificates of compliance on completion.
Frequently Asked Questions
What does a structural engineer do?
A structural engineer designs and assesses load-bearing structures, including foundations, beams, columns, floors, and walls, to ensure they are safe and fit for purpose. They produce structural drawings and reports required for building control, planning, mortgage lending, and insurance, and they certify compliance with structural design on completion of works.
Is a structural engineer the same as a civil engineer?
No, but the disciplines overlap. Structural engineering focuses on buildings and their structural elements; civil engineering focuses on infrastructure such as roads, drainage, and earthworks. Many engineers, including Banrach, are qualified and experienced in both disciplines, so projects crossing both disciplines can be handled by one practice.
Do I need a structural engineer to remove an internal wall?
If the wall is load-bearing, and in most Irish houses the walls between rooms on the ground floor are load-bearing, yes. Removing a load-bearing wall without a structural engineer's assessment and a beam design is illegal under building regulations and risks structural collapse. A Chartered Structural Engineer assesses whether the wall is load-bearing and, if so, designs the beam or steel needed to replace it.
Not Sure What You Need? Ask Banrach
Tell us about your property and what you're planning, whether that's a purchase, an extension, or a concern you'd like assessed. We'll advise on the right scope and respond with a quote.