Structural Engineer vs Architect: Who Do You Need for Your Project?
"Do I need an architect or a structural engineer?" is one of the most common questions homeowners ask when starting a building project. The answer is usually both — but at different stages and for different purposes. Understanding the difference prevents costly gaps in your professional team.
What Does an Architect Do?
An architect designs the project:
- Translates your aspirations into spatial layouts and design proposals
- Prepares drawings for planning applications
- Develops technical drawings for construction
- Specifies materials, finishes, and components
- Applies for planning permission on your behalf
- Acts as contract administrator (checking and certifying work) in some procurement routes
An architect's core skill is design — making your project look right, work well spatially, and integrate intelligently with the existing building and context.
What Does a Structural Engineer Do?
A structural engineer calculates and designs the load-bearing structure:
- Designs foundations for new extensions
- Calculates the size and specification of steel beams for new structural openings
- Designs structural frames for loft conversions
- Assesses structural adequacy of existing elements being altered
- Produces structural calculations and drawings required for Building Control
A structural engineer's core skill is ensuring the structure is safe and performs as intended.
When Do You Need Both?
Almost always for an extension, loft conversion, or structural alteration. The architect designs the layout and appearance; the structural engineer ensures the structure works. These are complementary, not alternative, appointments.
When Do You Need Only a Structural Engineer?
For projects that do not require planning permission or design input — such as removing a load-bearing wall in a house where you already know the layout you want — a structural engineer alone may be sufficient. They provide the calculations and drawings for Building Control.
When Do You Need Only an Architect?
Rarely in structural projects. An architect working on a planning application for an extension will always need to coordinate with a structural engineer at the technical design stage, even if the structural engineer is not needed for the planning application itself.
Design-and-Build vs Traditional
In a design-and-build contract with RCB, you often do not need to separately appoint your own architect and structural engineer. We coordinate both as part of the design-and-build service — managing the consultant team so you have a single point of contact for the whole project.
RCB Design & Build
RCB Design & Build coordinates architects, structural engineers, and other consultants as part of the principal contractor service — managing the pre-construction professional team on behalf of clients who prefer a single-point design-and-build approach.