Planning an extension, loft conversion, or structural alteration can raise many cost questions. One of the first is often how much a structural engineer will charge.
In the UK, structural engineer costs vary greatly between different types of work. A simple beam calculation may cost only a few hundred pounds. A complete structural design package for a large extension can cost considerably more.
For smaller home alterations, many homeowners pay a fixed structural engineer fee between £300 and £1,000. Across limited calculations and standard residential design work, costs can range from around £60 to £2,500, depending on exactly what is included. Complex residential projects and new builds can cost several thousand pounds.
Current UK cost guides show the same wide variation. Checkatrade’s June 2026 guide gives an average hourly rate of £100–£200, while MyBuilder lists structural inspections from roughly £175–£350.
The final cost depends on your property, project, location, and required drawings. Understanding these factors can help you compare quotes more fairly.
Structural Engineer Costs by Project Type
The following figures provide a broad UK guide for common residential projects.
| Service or project | Typical cost range | What it may cover |
|---|---|---|
| Hourly rate | £90–£200 | Consultations, investigations, or additional advice |
| Single RSJ or beam calculation | £60–£450 | Structural calculation for a defined beam or opening |
| Load-bearing wall removal | £300–£700 | Assessment, load calculations, and beam design |
| Chimney breast removal | £400–£800 | Structural support design for the remaining structure |
| Basic inspection and site visit | £175–£350 | Focused inspection of a particular structural concern |
| Defect or subsidence report | £500–£1,500 | Investigation, findings, and professional recommendations |
| Home extension structural design | £550–£2,500 | Foundations, beams, roof structure, and calculations |
| Loft conversion package | £750–£2,200 | Floor, roof, beam, and dormer structural design |
| Full new-build house design | £2,500–£6,000+ | Wider structural design and detailed calculations |
These figures are guide prices rather than fixed market rates. The lowest prices normally apply to very limited calculation work. Site visits, detailed drawings, several structural elements, revisions, and complex properties can increase the final fee.
Current 2026 published prices also vary between providers. Checkatrade reports an average £200 for an RSJ calculation, £400 for load-bearing wall work, and around £300 for a structural inspection. MyBuilder places inspections around £175–£350 and reports from roughly £500 upwards, depending on their scope.
How Much Does a Structural Engineer Charge Per Hour?
Structural engineer hourly rates commonly sit around £90 to £200 per hour. The final rate depends on experience, location, and the type of advice required.
Checkatrade’s current 2026 UK guide places average structural engineer hourly rates between £100 and £200. Other current UK pricing guides report rates beginning around £90 for some services.
Hourly pricing is more common when the exact amount of work is unclear. This might include investigations, meetings, design changes, or additional site advice.
For a clearly defined residential project, a fixed fee is often easier. It allows the homeowner and engineer to agree on the work before the project starts.
Structural Engineer Cost for an Inspection and Report
Not every structural concern needs a complete building design package. Sometimes a homeowner only needs an engineer to investigate one specific problem.
Basic Structural Inspection
A focused structural inspection may cost around £175 to £350.
The engineer may inspect a crack, a sagging floor, a roof concern, or suspected structural movement. The price will depend on the property and the amount of investigation required.
Current MyBuilder figures place general structural inspections within this £175–£350 range.
A site visit alone should not be confused with a detailed written structural report. Always check what documentation is included.
Structural Engineer Report
A written structural report usually costs more than a basic inspection.
A report may explain:
- what was inspected;
- visible structural concerns;
- possible causes;
- whether further investigation is recommended;
- whether repair or strengthening may be required.
Current UK pricing guides vary significantly. Checkatrade gives around £700 as an average report price, while MyBuilder places different reports between roughly £500 and £2,000 depending on their depth.
Defect or Subsidence Investigation
A more detailed defect or subsidence report may cost approximately £500 to £1,500, although difficult cases can cost more.
The engineer may need to assess cracking patterns, foundations, movement, previous alterations, nearby trees, ground conditions, or other evidence. Further investigations may also be recommended where the cause cannot be confirmed visually.
A specialist structural investigation should focus on the specific concern. It is different from a general property condition survey.
Structural Engineer Cost for Load-Bearing Wall Removal
Removing a load-bearing wall is one of the most common reasons homeowners contact a structural engineer.
Typical structural engineer fees may range from £300 to £700 for straightforward wall-removal projects.
The structural engineer normally needs to understand what the wall supports. Loads may come from floors, walls, roofs, or other structural elements above the opening.
The engineer can then design suitable support. This may involve a steel beam, supporting posts, padstones, or other structural details.
Current Checkatrade data gives around £400 as an average cost for structural engineering work involving a load-bearing wall.
The builder’s installation cost is separate from the structural engineer’s fee.
How Much Does an RSJ Calculation Cost?
A single RSJ or steel beam calculation can range from around £60 to £450, depending on the service provided.
At the lower end, the fee may cover only a limited calculation based on information already supplied. A higher fee may include a site visit, measurements, drawings, Building Control information, and supporting details.
Checkatrade’s 2026 UK guide currently gives around £200 as an average RSJ calculation cost. In London, its local data places broader structural calculation packages between roughly £443 and £808.
This difference shows why comparing quotes only by price can be misleading. One engineer may be providing much more information than another.
Structural Engineer Cost for Chimney Breast Removal
Structural engineer fees for chimney breast removal may fall around £400 to £800.
Removing part of a chimney can change how the remaining masonry is supported. The engineer may need to consider the chimney stack, floor structure, supporting walls, roof, and neighbouring construction.
The engineering work may include calculations and drawings for the required support. Building Regulations may also apply to structural alterations.
The price rises where several chimney breasts are involved or the existing structure is difficult to assess.
Structural Engineer Cost for a House Extension
A structural engineer for a house extension may cost approximately £550 to £2,500 for residential design work.
A small rear extension can require several different calculations. The engineer may need to assess both the new structure and the existing house.
What May Need Structural Design?
Depending on the project, structural engineering may cover:
- new foundations;
- steel beams;
- lintels;
- widened wall openings;
- columns;
- roof structure;
- floor structure;
- connections;
- load transfer into existing walls;
- support around large doors or glazing.
A simple extension will usually cost less than a large two-storey project. Complex ground conditions can also increase the amount of foundation design required.
Current pricing guides show considerable variation. Checkatrade states that a standard extension can start around £1,000 for engineering work, while other UK guides place many residential extension packages between several hundred pounds and roughly £1,500 or more.
The most useful approach is to compare the scope of each quote, not just the total figure.
Structural Engineer Cost for a Loft Conversion
Structural engineering for a loft conversion may cost around £750 to £2,200.
A loft conversion adds usable space within an area that was not always designed as a habitable floor. The existing structure therefore needs proper assessment.
The engineer may consider:
- new floor joists;
- steel beams;
- altered roof members;
- dormer structures;
- ridge support;
- load-bearing walls;
- new staircase openings;
- loads transferred to the structure below.
A simple rooflight conversion may need less engineering than a larger dormer, hip-to-gable, or mansard project.
More structural elements mean more calculations, drawings, and coordination. This is why two loft conversions of similar floor area can have different engineering fees.
Structural Engineer Cost for a New-Build House
Structural engineering for a new-build home may start around £2,500 to £6,000 or more.
Larger or more complex houses can cost considerably more.
Unlike a single wall alteration, a new building may require structural design across the whole property. This can include foundations, floors, roofs, beams, walls, columns, stability systems, and connections.
The structural engineer may also need to coordinate with architects, builders, Building Control, and other consultants.
For larger projects, engineering fees are sometimes agreed as a proportion of the overall construction cost. Current UK sources commonly place percentage-based arrangements around 1% to 3% for certain larger projects, rather than using one fixed percentage for every building.
What Affects Structural Engineer Fees?
No two properties are exactly the same. This is why a structural engineer often needs project information before giving a firm price.
Project Complexity
Complexity is one of the biggest cost factors.
Designing one beam is usually faster than designing several beams, columns, foundations, and structural connections.
An open-plan rear extension may involve existing walls, new steelwork, large glazed openings, and new roof loads. That requires more engineering time than one small opening.
Property Age and Construction
Older homes can require more investigation.
Victorian and Edwardian properties are common across London, South Harrow, Slough, and surrounding areas. They may contain old masonry, altered floor structures, historic chimney breasts, or previous extensions.
Older construction does not automatically mean higher fees. However, unclear or unusual construction can require more assessment.
Listed properties, historic buildings, and non-standard construction may also need specialist advice.
Location
Location can affect structural engineer prices.
London and parts of the South East often have higher professional fees than some other UK regions. Travel, operating costs, property complexity, and local demand can all affect pricing.
Current Checkatrade London data gives average structural calculations around £589, with a typical published range of approximately £443 to £808.
It is therefore reasonable to expect some London projects to cost more. However, claims that London is always exactly 20%, 30%, or 50% more expensive should be treated carefully because every quote depends on scope.
Number of Site Visits
One site visit may be enough for a straightforward project.
More complex work can require additional inspections. An engineer may need to return after part of the structure is exposed or when the design changes.
Ask whether additional visits are included in the original quote.
Drawings and Calculations
A verbal opinion is not the same as a full structural design package.
Structural calculations show how the engineer has assessed loads and designed structural elements. Drawings help communicate the design to builders and Building Control.
A project requiring detailed CAD structural drawings will usually cost more than basic calculations alone.
Revisions and Coordination
Projects often change.
A homeowner may widen an opening after the first design. An architect might alter the roof layout. Building Control may also ask for further information.
Check whether reasonable revisions are included. This can prevent unexpected fees later.
Fixed Fee vs Hourly Structural Engineer Costs
Most small domestic projects are well suited to a fixed fee.
A fixed quote may cover a defined service such as:
- one site visit;
- structural calculations;
- structural drawings;
- a report;
- agreed revisions.
This gives the homeowner better cost certainty.
Hourly rates are more suitable for work where the scope is unclear. Examples include investigations, ongoing advice, meetings, or unusual structural problems.
Larger projects may also use staged fees or percentage-based arrangements.
There is no single pricing method that suits every project.
What Should Be Included in a Structural Engineer Quote?
Never compare two quotes using the final figure alone.
One £400 quote might include only calculations. Another may include a site inspection, calculations, drawings, revisions, and Building Control responses.
A clear structural engineer quote should explain:
- the project scope;
- whether a site visit is included;
- what calculations will be prepared;
- whether structural drawings are included;
- how many revisions are allowed;
- whether Building Control queries are included;
- expected turnaround;
- VAT, where applicable;
- charges for extra visits or design changes.
Getting these details early makes budgeting much easier.
Why Structural Calculations Matter for Building Control
Structural engineering is not only about choosing a steel beam.
The design must show how loads are safely transferred through the building and into the ground.
In England, Approved Document A provides statutory guidance for the structural requirements of the Building Regulations. It covers matters including loading and ground movement.
Structural calculations may therefore be needed where work changes load-bearing parts of a property.
Common examples include:
- removing structural walls;
- creating large openings;
- constructing extensions;
- converting lofts;
- changing roof structures;
- designing foundations;
- adding significant new loads.
Building Control may review the structural information as part of the Building Regulations process.
The engineer’s role is to provide suitable professional calculations and details. Homeowners should not try to select beams or foundation sizes using generic online figures.
How to Avoid Unexpected Structural Engineering Costs
A clear brief is one of the easiest ways to control engineering costs.
Provide the engineer with available architectural drawings, existing plans, photographs, and details of the proposed work.
Tell them whether you need:
- calculations only;
- calculations and drawings;
- a site visit;
- a structural report;
- Building Control support;
- coordination with an architect or builder.
Changing the project after structural design has started can increase the fee.
For example, increasing a rear opening from three metres to five metres may change the beam, supports, foundations, and calculations. That can require part of the design to be completed again.
It is better to finalise the main layout before detailed structural design begins.
Is Hiring a Structural Engineer Worth the Cost?
For structural work, professional engineering should be viewed as part of the project rather than an optional extra.
A structural engineer helps establish whether the proposed work can safely support the loads placed upon it.
The engineer can also identify practical design issues before construction begins. Finding a structural problem on paper is normally easier than discovering it after building work has started.
Professional structural information also gives builders clearer instructions. This can reduce uncertainty during construction and help Building Control understand the proposed design.
The cheapest quote is therefore not always the cheapest option overall.
How Much More Does a Structural Engineer Cost in London?
Structural engineer fees in London often sit above prices seen in some other parts of the UK.
Current Checkatrade data for London places general structural engineer jobs around £425–£693, while structural calculations are listed around £443–£808. Structural design packages can cost considerably more.
However, postcode alone does not determine the price.
A simple property in London may require less engineering work than a complicated property elsewhere. The condition, age, design, and project scope remain important.
Homeowners in London, South Harrow, Slough, and nearby areas should therefore request a project-specific quote rather than relying only on a national average.
Frequently Asked Questions
How much does a structural engineer cost in the UK?
For smaller residential projects, structural engineer fees often fall between £300 and £1,000. Limited calculations can cost less, while extensions, loft conversions, surveys, and complex designs can cost £1,000 to several thousand pounds.
What is the average structural engineer hourly rate?
A typical UK structural engineer hourly rate is around £90 to £200. Current 2026 Checkatrade guidance places its average range at £100–£200 per hour.
How much does a structural engineer cost for a load-bearing wall?
A straightforward load-bearing wall project may cost around £300 to £700 for structural engineering. The exact price depends on the opening, loads, support arrangement, and drawings required.
How much does an RSJ calculation cost?
A single RSJ calculation may range from roughly £60 to £450 depending on scope. Calculation-only services sit towards the lower end, while site visits and drawings can increase the price.
How much does a structural engineer cost for an extension?
Structural design for a house extension may cost approximately £550 to £2,500. Larger extensions, unusual structures, and difficult foundations can increase the fee.
How much does a structural engineer cost for a loft conversion?
A typical loft conversion structural package may cost around £750 to £2,200. The conversion type and amount of roof or floor alteration have a major effect.
Does a structural engineer charge for a site visit?
Usually, yes.
A focused inspection may cost around £175 to £350. Some fixed design packages include the initial visit within the overall price.
Are structural calculations included in the engineer’s fee?
They may be, but never assume they are.
Ask whether the quote includes calculations, drawings, revisions, site visits, and responses to Building Control.
Do structural engineer prices include VAT?
Not always.
Some quotes include VAT while others show it separately. Check this before comparing prices.
Why do structural engineer quotes vary so much?
Quotes vary because engineers may be pricing different levels of work.
Property size, project complexity, location, site visits, drawings, calculations, revisions, and unusual structural conditions can all affect the fee.
Getting a Clear Structural Engineer Quote
There is no single structural engineer cost that applies to every UK property.
A small beam calculation may cost a few hundred pounds, while a full extension, loft conversion, defect investigation, or new-build design requires much more work.
Before appointing an engineer, provide clear project information and ask for an itemised scope. Check whether the price includes visits, calculations, drawings, revisions, and Building Control support.
For projects in London, Slough, South Harrow, and surrounding areas, RG Engineers can review the proposed work and provide a project-specific structural engineering quotation. The aim should always be a safe, practical design with a clear scope and no confusion about what the engineering fee covers.
