How much does a structural engineer cost in London?
For most London homes, a structural engineer's visit with verbal advice starts from £300 + VAT, a beam design from £400 + VAT and a full loft or extension package from £800 + VAT. This guide explains what sits behind those figures and why some jobs cost more.
The short answer
Structural engineering fees depend on what you need the engineer to produce, not on the value of the building work. A one-off visit to look at a crack is a small job. A full design for a rear extension, with foundations, steelwork and drawings for Building Control, is a larger one. A storey added to a block of flats is larger again.
The figures below are our published starting prices. A simple, clearly defined job with good access will usually come in at or close to the starting figure. The fee rises when the work has more parts, needs more information gathering or carries more risk. You know the number before you commit, because every job starts with a fixed fee that we confirm in writing before work begins.
Starting fees for common jobs
These are some of the most common structural jobs on London homes. All prices are from figures and exclude VAT.
- Site inspection with verbal advice: from £300 + VAT
- Specific Structural Inspection report (SSI) on one defined issue: from £450 + VAT
- General Structural Inspection report (GSI) on the whole building: from £650 + VAT
- Chimney breast or stack alteration design: from £350 + VAT
- Load-bearing wall opening design: from £400 + VAT
- Loft conversion structural package: from £800 + VAT
- Extension structural package: from £850 + VAT
- Underpinning design and sequence: from £1,000 + VAT
- Additional storeys and upward extensions: from £1,500 + VAT
What pushes a fee above the starting price
Two kitchen knock-throughs can look identical on a builder's quote and still need very different amounts of engineering. The difference usually comes down to how much the engineer has to find out, how many elements have to be designed, and how much depends on getting each one exactly right.
None of these factors is unusual in London housing stock. They are simply the reasons a fixed fee is set per job rather than from a single tariff.
- The number of structural elements: one beam is quicker to design than a beam, two columns, a new foundation and a flat roof
- Unknowns in the existing building, such as hidden alterations, removed chimney breasts or floors that have already been cut
- Whether opening up is needed to see bearings, joists or foundations before a design can be finalised
- Party walls, basements, cantilevers and transfer beams, which all need more checking
- Ground conditions, especially London Clay near trees, where foundation depth needs a closer look
- Missing drawings, which may mean a measured survey before design can start
- The number of site visits and any inspections needed during construction
Inspection fees and design fees are different things
It helps to know which of two broad services you are paying for. An inspection answers a question about an existing building: is this crack serious, is this wall load-bearing, is the structure sound enough to buy. The output is advice or a written report.
Design creates something new. The engineer sizes beams, columns, joists and foundations, produces calculations and drawings, and answers Building Control's questions about them. Design takes longer and carries more responsibility, which is why packages for extensions and lofts start higher than reports.
If you are not sure which inspection you need, our guide on choosing a structural inspection report compares the options side by side. For design work, the guide to structural calculations explains what you receive for the fee.
Costs that sit outside the engineer's fee
A structural engineer's quote covers the engineering. Most projects have other professional and statutory costs alongside it, and it is worth budgeting for them from the start rather than discovering them halfway through.
Building Control charges are set by your council or by the private approver you appoint, and are paid directly to them. If the work affects a shared wall, party wall surveyors' fees may apply under the Party Wall etc. Act 1996. Building near a public sewer may need an application to Thames Water. Trial pits, ground investigation and drainage surveys are separate pieces of work, quoted when the project needs them.
If you want one firm to handle more of this, some of it can sit with us. For example, our party wall notices and schedule of condition service and our drainage surveys are quoted separately and can run alongside the structural design.
How to get an accurate quote quickly
The more we know at the start, the closer the fixed fee will be to what the job really needs, and the fewer surprises there will be later. A few photos often do more than a long description.
Our typical turnaround is 10 working days, confirmed in writing with the fee, so it pays to ask early if you have a builder booked or a purchase deadline.
- The postcode and the type of property (terrace, semi, flat, conversion)
- Photos of the wall, crack, loft or area involved, with something for scale
- Any architect's drawings or planning drawings you already have
- What you need at the end: advice, a report, calculations for Building Control, or a full design package
- Your timescale and whether a builder is already involved
Comparing quotes fairly
A lower quote is not always cheaper by the end of the job. When you compare, check what is actually included. Does the fee cover drawings as well as calculations? Does it include responding to Building Control queries? Is a site visit included, or is the design done from photos? How are changes charged?
Ask who checks the work. On our side, each design and calculation set is checked in three separate steps, and our Head of Engineering signs off the final version. That checking is part of the fee, and it is what keeps a beam from being redesigned on site when the builder finds something unexpected.
Frequently asked questions
Are your prices inclusive of VAT?
No. All our published prices are from figures that exclude VAT, so VAT is added at the standard rate. The fixed fee we confirm in writing before work starts shows the net figure and the VAT clearly, so there is no ambiguity about the total you will pay. If you are a VAT-registered developer or landlord, you may be able to reclaim it, and your accountant can confirm that.
Is the fee fixed, or can it go up during the job?
Every job starts with a fixed fee confirmed in writing before any work starts, based on the scope we agree. If the scope stays the same, the fee stays the same. If you later change the design, for example moving an opening or switching from a downstand to a flush beam, we quote the change separately. Our structural design revision service starts from £150 + VAT.
Does the engineer's fee include Building Control charges?
No. Building Control charges are paid directly to your council or to the private approver you appoint, and they set their own fees. Our fee covers the engineering itself. On design jobs we send the calculations and drawings to Building Control and deal with their questions, so you do not have to relay technical queries between the inspector and the engineer yourself.
Why does a loft conversion cost more than a single beam?
A loft package covers many elements rather than one. The engineer designs new floor joists, steel beams, any ridge or purlin supports, connections, padstones and often checks walls and foundations below. There are usually more drawings, more Building Control questions and more chance of finding something unexpected in the roof. A single beam design is one element with two bearings, so it takes less time to complete and check.
Is it worth paying for an engineer on a small job?
Usually yes, if the job is structural. A beam or a chimney breast alteration still needs calculations for Building Control, and getting them right at the start costs far less than putting right an undersized beam later. For a quick opinion on a crack or a wall, a site inspection with verbal advice is the lowest-cost way to find out whether you need anything more.