Concrete Design Costs: Understanding the True Cost of Professional Design

When a contractor tells you they need "engineer's drawings" before they can start, the cost of professional design work can come as an unwelcome surprise. Design fees are rarely discussed upfront, yet they are a compulsory part of most structural building projects in the UK — legally required under Building Regulations and essential for a contractor to price and build safely. Understanding how structural engineers, civil engineers, and other design consultants charge for their work puts you in a much stronger position when requesting and comparing quotes.

Key points

• Structural engineering design fees in the UK typically range from around £500 for a simple beam or lintol calculation to £8,000+ for a full new-build or complex extension structural package (Indicative UK costs, last reviewed 2026-05-24).
• Most structural engineers charge using one of three models: a fixed fee for a defined scope, a percentage of construction cost (commonly 5–12%), or an hourly rate (typically £75–£150/hr for a chartered engineer).
• Building Regulations Approved Document A (Structure) requires that structural work is designed by a competent person — in practice, most building control bodies expect a chartered structural engineer (MIStructE or MICE) for anything beyond minor works.
• Civil engineering design — covering drainage, groundworks, retaining structures, and highway access — is a distinct discipline from structural engineering; on larger or more complex sites you may need both.
• Design fees are generally subject to VAT at 20%, and most firms carry professional indemnity (PI) insurance; always check the policy limit matches your project value.

How structural design fees are structured

Professional design fees take three main forms in the UK:

Fixed fee — a lump sum agreed upfront for a clearly defined scope. This is the most common arrangement for residential projects such as loft conversions, single-storey extensions, and beam or lintol design. Fixed fees work well when the scope is stable; they can increase if the project changes materially after the fee is agreed.

Percentage of construction cost — typically 5–12% for structural engineering on residential projects, rising towards 15% for complex or unusual schemes. This model is more common on larger projects where the final scope is uncertain at the outset.

Hourly rate — used for smaller, loosely defined commissions or when additional work arises during a project. Expect £75–£150/hr for a chartered engineer; specialist or senior engineers may charge more.

Some firms blend approaches — a fixed fee for the design stage with an hourly rate for any queries from building control or the contractor during construction.

What the fee usually includes

• Structural calculations (the engineering analysis)
• General Arrangement drawings and detail drawings
• Specification notes for the contractor
• Liaison with the building control body or approved inspector
• A defined number of site visits or queries during construction

What it often does not include: planning application drawings (that is usually the architect's scope), Party Wall Award preparation, specialist surveys such as ground investigation or drainage survey, or unlimited queries from contractors during the build.

Comparison: design professionals for residential projects

Indicative UK costs, last reviewed 2026-05-24. Fees vary significantly by firm, region, and project complexity.

What drives the cost up or down?

Complexity of the structure — a single steel beam over a knocked-through wall is straightforward to calculate. A three-storey rear extension with a new basement requires far more engineering input.

Ground conditions — if soil investigation is needed (trial pits, borehole logs), this adds cost before the structural design can even be completed. Poor ground conditions such as made ground, filled land, or a high water table require more conservative and more expensive foundation solutions.

Number of revision rounds — if planning is still evolving when you appoint an engineer, late changes to the design can trigger additional fees. Appoint your structural engineer once the design intent is reasonably fixed.

Location — London and south-east England generally attract higher fee rates than other UK regions.

Building control submissions — some engineers include preparation and submission of structural design information to building control within their fee; others charge separately.

Homeowner checklist: what to prepare before requesting a design quote

The more complete your brief, the more accurate your quote will be. Gather this information before contacting a structural engineer or civil engineer:

• Existing floor plans or measured survey drawings (even a rough sketch helps)
  
• Planning permission reference number if already granted
  
• Age and construction type of the property (e.g. Victorian solid wall, 1930s cavity, post-war concrete frame)
  
• Description of the proposed work (e.g. remove load-bearing wall, add loft dormer, build rear extension)
  
• Any known issues: subsidence history, previous structural work, damp, filled ground
  
• Name of your building control body (local authority building control or an approved inspector)
  
• Contractor name if already appointed — some engineers liaise directly with site
  
• Your programme — when do you need drawings for building control submission?
  

What to ask before accepting a design quote

• What is specifically included in this fee — calculations, drawings, and what level of building control support?
• What qualifications and accreditations do you hold (MIStructE, MICE, CEng)?
• Does your professional indemnity insurance cover my project type and value?
• What information do you need from me before starting?
• What will trigger additional fees, and at what rate?
• Is VAT included in this figure?
• What is your expected turnaround time for the initial design?
• Have you worked on similar projects (e.g. Victorian terraces, concrete-frame flats, or timber-frame buildings) before?

When to get professional help

A structural engineer is not optional for most structural alterations in the UK — building control will require evidence that the structure has been professionally designed. Seek professional design input whenever you are:

• Removing or altering any wall, even if you are unsure whether it is load-bearing
• Adding a storey, dormer, or significant roof alteration
• Excavating for a basement or large extension
• Noticing cracks, movement, or deflection in an existing structure
• Installing a new roof structure, floor, or mezzanine

Do not rely on a contractor's informal assessment of whether a wall is load-bearing. If the contractor is not a chartered structural engineer, get independent design sign-off before work proceeds.

How Housey can help

Housey connects you with qualified structural engineering services professionals and civil engineers who can provide fixed-fee quotes for your project. Compare credentials, fee structures, and scope of service before you commit.

Frequently asked questions

Do I need both an architect and a structural engineer?

Not always. For straightforward structural work such as beam design or loft conversion structural calculations, a structural engineer alone may suffice. If your project requires planning drawings, a full design package, or project management, an architect is usually needed alongside the engineer. Many firms offer combined services, which can simplify communication and reduce coordination costs.

Can a structural engineer submit my building control application?

Yes. A structural engineer can prepare and submit the structural design information required for a building regulations application. However, building control covers more than structural work — fire, drainage, and insulation are also assessed. You or your architect will usually manage the overall submission, with the engineer contributing their structural section.

Is VAT charged on structural engineering fees?

Structural engineering design services are generally subject to VAT at the standard rate of 20%. Always check whether quoted fees are stated inclusive or exclusive of VAT before comparing proposals. On a £3,000 design package, VAT adds £600 — a meaningful difference in your project budget.

How do I check a structural engineer's credentials?

Look for membership of the Institution of Structural Engineers (MIStructE or FIStructE) or the Institution of Civil Engineers (MICE or FICE), and Chartered Engineer (CEng) status via the Engineering Council. You can verify current membership directly on the IStructE website or ICE's Find an Expert directory before appointing.

Sources and further reading

• Building Regulations Approved Document A (Structure) — GOV.UK
• Find an Engineer — Institution of Structural Engineers
• Find an Expert — Institution of Civil Engineers
• UK Standard for Professional Engineering Competence (UK-SPEC) — Engineering Council