Structural engineer or architect — who do you need for your project? Many homeowners are unsure about the distinction, and some are surprised to discover they need both. The roles are complementary but distinct, and understanding what each professional does will help you assemble the right team for your project and avoid wasting money on the wrong appointment. Crown Architecture & Structural Engineering provides both services under one roof, which simplifies the process considerably. Call us on 07443804841 to discuss what your project needs.

What Does an Architect Do?

An architect is responsible for the design of a building — how it looks, how it works, how it relates to its surroundings, and how it meets the client’s brief. Specifically, an architect:

• Develops the spatial design: room layouts, circulation, light, proportion, and appearance
• Produces planning drawings for submission to the Local Planning Authority
• Prepares specifications — what materials, finishes, and products are used
• Produces construction (working) drawings for the contractor to build from
• Manages the planning and Building Regulations processes
• May administer the building contract — issuing instructions, certifying payments, managing variations
• Coordinates the inputs of other consultants (structural engineer, M&E engineer, acoustic engineer, etc.)

Architects are qualified professionals registered with the Architects Registration Board (ARB). Only ARB-registered professionals can call themselves “Architect” — it is a protected title. Many architects are also members of the Royal Institute of British Architects (RIBA), denoted by the suffix RIBA after their name.

What Does a Structural Engineer Do?

A structural engineer is responsible for the structural integrity of a building — ensuring that it stands up safely under all loads it will experience. Specifically, a structural engineer:

• Calculates the loads acting on a structure (dead loads from the building’s own weight, imposed loads from occupants and furniture, wind loads, snow loads)
• Designs structural elements — foundations, beams, columns, floor structures, retaining walls — to safely carry those loads
• Produces structural drawings and calculations for Building Regulations submission
• Specifies structural materials — steel sections, concrete mixes, timber grades
• Advises on the structural implications of architectural proposals (can this wall be removed? how does this opening affect the structure?)
• Visits site to inspect structural work during construction
• Provides structural condition assessments for existing buildings

Structural engineers are qualified professionals registered with the Institution of Structural Engineers (IStructE) or the Institution of Civil Engineers (ICE). Look for the designations MIStructE, FIStructE, or CEng after their name.

How the Two Roles Relate

Architecture and structural engineering are deeply intertwined. The architect creates the design intent; the structural engineer makes it work safely. A beautifully designed open-plan extension with a large glazed rear wall requires a structural engineer to design the steel beam that makes the wide opening possible. A dramatic cantilevered upper floor requires a structural engineer to verify that the structure will hold it.

In practice, architects and structural engineers work iteratively. The architect proposes a design; the structural engineer advises on what is feasible and at what cost; the architect refines the design; the engineer sizes the structure accordingly. Good collaboration between the two produces buildings that are both beautiful and structurally efficient.

Crown Architecture & Structural Engineering integrates both disciplines in-house, which means this iterative dialogue happens quickly and efficiently, without the delays and coordination costs of appointing two separate practices.

When Do You Need an Architect?

You need an architect when you need design input, planning drawings, or full construction documentation. Specifically:

• Any project requiring planning permission — the architect prepares and submits the planning drawings and supporting documents
• Any project where the spatial layout, appearance, or function of the building needs professional design
• Complex projects where coordination of multiple consultants and contractors is needed
• Projects in Conservation Areas, on Listed Buildings, or where design quality is scrutinised by the planning authority
• Where you want a contract administrator to manage the building works and protect your interests

When Do You Need a Structural Engineer?

You need a structural engineer when structural work is involved. Specifically:

• Any extension that requires new foundations, floor structures, or roof structures
• Removing a load-bearing wall (the engineer designs the replacement beam)
• Loft conversions (new floor structure, dormer structure, roof alterations)
• Basement conversions (underpinning, retaining walls, waterproofing design)
• Structural condition assessments for buildings showing distress (cracking, movement, subsidence)
• Pre-purchase structural surveys for complex or distressed properties
• Any project where Building Regulations require structural calculations to be checked by Building Control

When Do You Need Both?

For most building projects involving both design and structural work — extensions, loft conversions, new buildings — you will need both. The architect handles design, planning, and documentation; the structural engineer handles the structural design and calculations. Both sets of drawings feed into the Building Regulations Full Plans application.

Some smaller projects need only one or the other. A single load-bearing wall removal in a house may need a structural engineer (for the beam design and Building Regulations calculations) but not necessarily an architect, if the spatial design is straightforward. Conversely, a planning application for a rear extension that involves no structural complexity may be handled by an architect alone, with the structural engineer appointed later when building work is ready to start.

Can One Person Do Both?

Architecture and structural engineering are separate professions requiring separate qualifications. However, some practices — like Crown Architecture & Structural Engineering — offer both services in-house. This is genuinely beneficial: it reduces coordination delays, can reduce overall fees, and ensures that structural and architectural considerations are developed together from the outset rather than being resolved as conflicts arise.

Be wary of firms that claim to provide structural engineering services but do not have a Chartered Structural Engineer (MIStructE or CEng) on the team. Structural calculations for Building Regulations must be signed off by a qualified structural engineer.

Typical Fees: Architect vs Structural Engineer (2025)

Fees vary significantly by project scale and complexity. Indicative ranges:

Architect fees for a house extension:

• Planning drawings only: £2,000–£6,000 depending on size and complexity
• Planning + Building Regulations drawings: £4,000–£10,000
• Full service (planning, Building Regulations, contract administration): £6,000–£20,000+

Structural engineer fees for a house extension:

• Structural calculations and drawings for a single-storey extension: £800–£2,000
• Two-storey extension or loft conversion: £1,500–£4,000
• Complex project with basement, significant steel, or unusual structure: £3,000–£10,000+

When both services are provided by the same practice (as at Crown Architecture & Structural Engineering), the combined fee is typically lower than engaging two separate practices.

How to Choose the Right Professionals

When selecting an architect or structural engineer for your project, look for:

• Relevant experience: Ask to see examples of similar projects (similar scale, type, and planning context)
• Qualifications: Architects should be ARB-registered; structural engineers should hold MIStructE, FIStructE, or CEng
• Local knowledge: Particularly for planning applications, experience with your local authority’s preferences and policies is valuable
• Communication: You will work closely with these professionals for months — choose someone who listens to your brief and communicates clearly
• Fees: Get at least two quotes and compare what is included. A low fee for planning drawings alone may not include the construction information you need to get Building Regulations approval

Frequently Asked Questions

Do I need a structural engineer if I already have an architect?

For most building projects involving new structures or alterations to existing ones, yes. The architect handles design and documentation; the structural engineer handles the structural calculations that Building Control must approve. Unless your architect has a structural engineer in-house (as Crown Architecture & Structural Engineering does), you will need to appoint one separately.

Can a structural engineer design my extension without an architect?

A structural engineer can produce the structural drawings and calculations needed for Building Regulations, but cannot produce architectural design drawings for planning permission. For projects requiring both planning permission and Building Regulations, you need both disciplines.

What is a “technician” and is it the same as an architect?

Architectural technicians (MCIAT — Member of the Chartered Institute of Architectural Technology) produce technical drawings and construction documentation but are not registered with the ARB as architects. They can prepare planning and building regulations drawings for most residential projects and are often more cost-effective than architects for straightforward projects. For design-led or complex projects, a qualified architect adds more value.

Should I appoint the architect or the structural engineer first?

Usually the architect first, since they lead the design and Brief process and coordinate the appointment of other consultants including the structural engineer. At Crown Architecture & Structural Engineering, both are available from the outset — call 07443804841 and we will advise on the most appropriate scope of appointment for your project.

What happens if the architect and structural engineer disagree?

Disagreements between architects and engineers are a normal part of the design process and are usually resolved collaboratively. Having both in-house, as at Crown Architecture & Structural Engineering, eliminates the coordination friction that can arise between separate practices with separate fee interests.

Crown Architecture & Structural Engineering provides both architectural design and structural engineering services for residential and commercial projects across the UK. Call 07443804841 for an initial consultation.