Structural engineer fees by service
Typical UK costs for common structural engineering services in 2026.
| Service | Typical cost | Notes |
|---|---|---|
| Initial phone / desk consultation | Free to £150 | Many engineers offer a free initial call. |
| Site visit and verbal advice | £150 to £350 | Usually includes brief notes but no formal report. |
| Site visit plus written report | £300 to £500 | Formal report suitable for building control or insurance purposes. |
| Structural calculations for a steel beam (RSJ) | £400 to £1,000 | Required for most load-bearing wall openings. Includes spec for beam size. |
| Structural calculations for a loft conversion | £600 to £1,500 | Covering joists, purlins and ridge beam where applicable. |
| Structural drawings for a single-storey extension | £800 to £1,500 | Foundation, wall and beam details for building regs submission. |
| Structural drawings for a two-storey extension | £1,200 to £2,500 | More complex load paths and foundation design. |
| Subsidence investigation and report | £400 to £1,200 | May include soil investigation; insurance-linked reports at the higher end. |
| Hourly rate (London / South East) | £150 to £250 per hour | Higher cost in major cities. |
| Hourly rate (rest of UK) | £90 to £175 per hour | Varies by firm size and experience. |
Fees exclude VAT. Costs in London are typically 20-40% higher than the UK average.
When do you need a structural engineer?
A structural engineer is required or strongly recommended in these common home improvement scenarios:
- Removing or altering a load-bearing wall: you need calculations to specify the correct steel beam (RSJ) and padstone to safely carry the load above.
- Single or two-storey extensions: structural drawings are typically required for building regulations approval, covering foundations, lintels and wall construction.
- Loft conversions: calculations are needed for strengthened floor joists, new structural ridge beams and any purlin alterations.
- Basement conversions: underpinning or retaining wall design requires specialist structural input.
- Garage conversions: if the garage roof forms part of the house structure or the party wall is affected, a structural check is advisable.
- Subsidence or cracking: an engineer can determine whether movement is active, its likely cause, and whether remedial work is needed.
- Purchasing a property with structural concerns flagged in a survey: an independent structural report clarifies risk before you exchange.
- Flat roof or conservatory replacement on a larger structure: load calculations ensure the existing structure can bear the new weight.
What structural calculations actually include
When you open up a load-bearing wall to create an open-plan space, the structural engineer's job is to calculate exactly what steel beam is required to support the load above safely. This involves assessing the span of the opening, the load from floors and roof above, and specifying the correct RSJ section and bearing length, along with padstones (load-spreading blocks) at each end.
The engineer produces a set of signed calculations and often a simple sketch. Your builder uses these to order the correct steel, and your building control officer uses them to approve the work. Without signed calculations, building control will not sign off the work, and when you sell, the lack of a completion certificate will appear on searches.
For an extension or loft conversion, structural drawings go further, covering foundation depth and type (strip, pad or raft), wall construction, floor joist sizing, roof structure and any temporary works needed during construction.
Never skip structural sign-off to save money
Builders who say 'I've done hundreds of these, we do not need an engineer' are taking a legal and safety risk on your behalf. If the beam or foundation is under-specified and the structure fails or is condemned by building control, the cost of remediation will far exceed the engineer's fee. A missing building regulations certificate also causes real problems at sale, often delaying or killing transactions.
How to find and appoint a structural engineer
Tips for getting the right engineer at a fair price:
- Look for members of the Institution of Structural Engineers (IStructE) or the Institution of Civil Engineers (ICE): designations include MIStructE, FIStructE, MICE and FICE.
- Ask your architect or builder for a recommendation, but remember the engineer works for you, not your contractor.
- Get two or three quotes for larger or more complex projects; smaller jobs such as a single beam calculation are fairly standardised.
- Check that the engineer has professional indemnity insurance, which protects you if their calculations are negligent.
- Agree the scope in writing before work begins: specify what calculations and drawings are included, the format of the output, and whether building control liaison is included.
- Factor the fee into your budget before you exchange, particularly if a survey has flagged structural concerns.
Budget for structural costs before you commit
Our planner helps you set a realistic buying and refurbishment budget before you commit. Add structural engineer fees as a line item alongside your architect, planning, and building regulations costs so nothing is overlooked.