A structural engineer doesn’t have one fee, because “structural engineer cost” actually covers at least four different jobs. A site visit and a verbal opinion on a crack or a proposed opening costs £175–£350. A written report on a specific problem — is this crack getting worse, can this wall come out — runs £500–£1,200, occasionally up to £2,000 for something more involved. Calculations and drawings for a loft conversion or a single-storey extension, the kind building control wants to see before work starts, typically cost £500–£1,500. And a genuinely complex job — multiple steels, a mansard roof, a basement, or the design behind underpinning — can run from £1,500 to £10,000 or more, sometimes billed by the hour at £90–£200.
The number that matters isn’t an average across all of that — it’s which of those four jobs you actually need, and that’s usually the question a worried look at a crack or a builder’s quote can’t answer on its own.
I’m a building surveyor, not a structural engineer — I diagnose and refer on, I don’t do the calculations myself, so I’ve no reason to talk you into a job you don’t need. What follows is 2026 pricing cross-checked against current UK cost guides, what actually drives the number, when a surveyor sends you to a structural engineer in the first place, and why chartered status matters more in this trade than the quote alone will tell you.
The short answer
Figures below were checked on 7 August 2026 against current 2026 cost guides from Checkatrade, HomeOwners Alliance and specialist structural engineering practices, cross-referenced against each other rather than taken from a single source. As with most trades in this series, engineers in London and the South East — Dom’s patch included — commonly charge 15–25% above the national figures quoted here.
| Job | Typical cost (2026) | What's included |
|---|---|---|
| Site visit, verbal opinion only | £175–£350 | An engineer looks at the problem on site and gives a spoken view — no written report or calculations |
| Written report on a specific defect | £500–£1,200 | Site visit plus a written finding on a crack, a beam, or a suspected structural issue |
| Calculations for a loft conversion or extension | £500–£1,500 | Sized steels, drawings and the calculations building control needs before work starts |
| Complex or ongoing work (multiple steels, subsidence, underpinning design) | £1,500–£10,000+ | Full design package, building control liaison, and often return site visits during the works |
Those bands land close together across the trade guides despite each pricing slightly differently, which is a reasonable sign they’re real rather than one outlier’s number. The gap between the top and bottom of that range is wider than in most trades in this series, because “structural engineer” genuinely covers everything from a ten-minute opinion to months of involvement on a subsidence claim.
What drives the price
Scope. A verbal opinion, a written report and a set of stamped calculations are three different products at three different price points, and it’s worth being explicit with the engineer at the outset which one you’re asking for — a quote for “a look at my crack” and a quote for “a report I can show my insurer” are not the same job even if the site visit looks identical.
Complexity of the structure. One beam over one opening is a fixed-fee job for most practices, typically £300–£600. Multiple steels, a mansard conversion, a basement, or a structure that’s already moved and needs monitoring before it can be designed for pushes the fee toward the top of the range or into hourly billing.
Property age, construction and access. Older solid-wall houses, timber-framed buildings, and anything where the engineer can’t see the structure without opening up finishes first take longer to assess and cost more to report on than a straightforward modern timber-frame extension.
Revisions and building control liaison. A fixed fee that includes redesigning a steel size if the contractor’s preferred beam doesn’t fit, and answering building control’s follow-up queries, costs more than a one-off calculation — and is worth paying for, because those queries are routine, not a sign anything’s wrong.
Region. London and the South East commonly run 15–25% above the national figures quoted here, in line with most trades in this series.
When a surveyor sends you to a structural engineer
Most of what I see on a survey is not a structural engineer’s job. Hairline cracking that follows a plasterboard joint, seasonal movement around a door frame, or a crack that’s been decorated over more than once without reappearing is far more often cosmetic or thermal movement than anything needing calculation — and sending every worried client off to pay £500 for a report on it would be a poor use of their money and my judgement. Telling the two apart is a good part of what a survey is for.
Where I do refer on: cracking that’s recent, wider than a few millimetres, running diagonally from an opening, or turning up alongside sticking doors and windows — the pattern that suggests subsidence rather than seasonal movement, and needs an engineer to establish the cause before anyone talks about underpinning. Removing or altering a load-bearing wall or chimney breast, whatever the builder doing the work says about how straightforward it is. A loft conversion or extension, because building control will want calculations regardless of how simple the job looks from the outside. And roof spread, bowing walls or deflection beyond what a visual inspection alone can safely judge.
If it’s a subsidence claim going through buildings insurance, the insurer will usually instruct and pay for their own structural engineer directly — worth knowing before you commission and pay for a second one yourself.
Chartered or not — why it matters
“Structural engineer” isn’t a protected title in the way “chartered surveyor” is — anyone can call themselves a structural designer. What you actually want is someone chartered through the Institution of Structural Engineers (MIStructE or CEng) or the equivalent, carrying professional indemnity insurance at a level that matches the job — typically at least £250,000, more for anything involving underpinning or a basement.
This matters more here than in most trades, because a cheap set of calculations from an uninsured or unqualified designer can be rejected by building control outright, or accepted at the time and then queried by a buyer’s solicitor or a mortgage lender’s surveyor years later, with no PII behind it to fall back on if it turns out to be wrong. Paying more for a chartered engineer’s calculations isn’t belt and braces — it’s buying a sign-off that actually holds up when someone else has to rely on it.
What I'd watch for in a quote
- Chartered status and PII level stated up front — MIStructE/CEng membership of the Institution of Structural Engineers, and the actual insurance figure, not just “fully insured”.
- Whether the fee is fixed or hourly, and what's included — ask specifically whether redesign, revisions and building control queries are covered or charged again.
- Clarity on what you're actually buying — a verbal opinion, a written report, or stamped calculations are different products; get it in writing which one the quote covers.
- How return site visits are charged on anything involving monitoring or phased works, such as a suspected subsidence case or underpinning — these can add up over months.
- A written scope setting out exactly which part of the property is being assessed, in the same way a surveyor's own terms of engagement should be specific.
Questions I get asked
How much does a structural engineer cost in 2026? A site visit and verbal opinion typically costs £175–£350. A written report on a specific defect runs £500–£1,200, and calculations for a loft conversion or extension typically cost £500–£1,500. Complex jobs — multiple steels, a basement, or subsidence and underpinning design — can run from £1,500 to £10,000 or more, and London and the South East commonly run 15–25% above these figures.
Do I always need a structural engineer, or can my surveyor just tell me? Not always. A lot of the cracking a surveyor sees is seasonal or cosmetic movement that doesn't need an engineer at all, and part of a survey's value is telling that apart from something that does. Where a surveyor refers you on is where calculations are actually needed — removing a load-bearing wall, a loft conversion or extension, or cracking that fits the pattern of ongoing structural movement rather than seasonal movement.
What's the difference between a structural engineer and a party wall surveyor? They're different professionals doing different jobs, even though both can get involved on the same extension or loft conversion. A structural engineer designs the steelwork and produces the calculations building control needs. A party wall surveyor deals with the legal notice and award process where work affects a shared wall with a neighbour — a separate cost, typically another £700–£1,500 per neighbour if they appoint their own surveyor rather than giving written consent.
Will building control accept any structural engineer's calculations? Not automatically. Building control is more likely to query calculations from an unqualified or uninsured designer, and a lender or buyer's solicitor further down the line may ask who produced them and what insurance stands behind them. A chartered engineer's stamped calculations, backed by proper professional indemnity insurance, are far less likely to cause a problem at either stage.
If a survey turns up a crack, a bulge, or a wall you're hoping to remove, the useful next step is usually an independent read on whether it's actually a job for a structural engineer at all — that's exactly what my building survey work is for. Call 07946 618203 or get in touch and I'll give you a straight answer before you pay for calculations you might not need.
Small print. This guide is general information, not advice on a specific property, and it doesn’t replace a proper survey and quote for your own home. Prices were researched and correct to the best of my knowledge on 7 August 2026; costs move and vary by region and property. Always get at least three written quotes, and check an engineer's chartered status and professional indemnity insurance before instructing them.