Hiring a structural engineer is key for certain kinds of property construction or renovation projects, ensuring that any structural work complies with Building Regulations. Without a specialist engineer on your team, you can’t be sure that your designs and their implementations are structurally sound.

So, what does a structural engineer do exactly, and when do you need one to work alongside architects and builders? This blog explores everything you need to know about hiring structural engineers, to help you understand whether you require one or not – so read on to learn more.


What is a structural engineer?

Put simply, a structural engineer specialises in the safety and durability of building structures. Based on their initial assessments, they can calculate loads to help you determine design specifications, and recommend the best construction materials and methods for maximum structural integrity.

These engineers often report to architects and building contractors like a consultant, advising them on appropriate courses of action. They will oversee construction works and carry out inspections to make sure everything is up to legal standards, so Building Control can sign off on your application.

Structural engineers can assist with designing new buildings or altering existing structures, including residential and commercial buildings and city infrastructure. In the case of existing buildings, they can identify construction defects and suggest solutions for fixing them to the appropriate standard.

Do I need a structural engineer or an architect?

You might be wondering what the difference is between structural engineers and architects, and why you would need them both. An architect is more like an artist, focusing more on the aesthetics of the building – though they do have to take planning permissions and regulations into account.

On the other hand, structural engineers focus solely on the building’s structural stability rather than its appearance and functionality for the end users. While architects create design drawings and 3D models, these engineers consider the load support requirements and advise on structural materials.

You’ll only need an architect if you’re undertaking a new build or extensive renovation project that you can’t design on your own. Regardless of the complexity of the construction, you’ll always need a structural engineer to consult on any work that concerns the strength of the building’s structure.


Why would I need a structural engineer?

If you’re building a load-bearing structure, or carrying out renovations or conversions that add further loads to an existing structure, you’ll need a structural engineering expert to make sure you do it correctly. Occasions that are likely to require the advice of a structural engineer include:

Structural alterations

Whether you’re designing a new building or altering an existing one, you’ll need the technical specs that a structural engineer can calculate for you to avoid or secure planning permission requirements. You’ll also need them to inspect the work and submit an application for Building Control approval.

Aside from creating a whole new structure from scratch, which will definitely require an architect as well, projects that require a structural engineer include (but are not limited to):

Removing or knocking through a wall
Installing solar panels on a roof
Removing a chimney breast
Modifying windows and doors
Underpinning floors (strengthening foundations)
Adding a porch, veranda, balcony, or deck
Converting a loft or garage
Building an adjoining extension

Basically, any time you’re adding or removing a load-bearing element, or adding any extra weight – even if it’s just installing a hot tub on an existing deck or balcony, for example – you should engage a structural engineering expert. They will assess whether anything needs to be done to make it safe.

Structural inspections

Any time you’re buying a property, it’s advisable to get a chartered surveyor to inspect it first. If they find a structural issue during their inspections, they’re likely to recommend a structural engineer to assess the problem. The engineer will be able to identify the cause and explain what to do to fix it.

Their more detailed investigation of the damage can diagnose structural failures like the following:

Subsidence (sinking ground)
Settlement (compressed foundations)
Cracks in ceilings, walls, or floors
Bowed ceilings or warped floors
Sagging roofs (e.g. due to water ingress)
Crumbling concrete or mortar

Failing to address defects like these, and take the recommended steps to correct them, can have serious consequences – from the roof falling down to the building collapsing completely. Even if it’s not an inherent defect, and the visible damage to the building is obvious (e.g. fire, flooding, weather, vehicle collisions etc), you’ll still need a structural engineer to assess its stability and reparability.

Expert witness services

As a property owner or developer, you may find yourself in a legal dispute with another party at some point. If the appropriate insurance policies are all in place, including a structural warranty, then you shouldn’t have too much trouble making a building insurance claim or securing financial compensation for latent structural defects, which you can use to cover the costs of building repairs.

Should you end up having to take the other party to court over property damage and losses or injuries resulting from structural failures, you’ll need a qualified expert witness to present the facts in your case. A structural engineer will have the specialist knowledge required to assess the defects and their causes, their compliance with Building Regulations, and their risks to health and safety.


When will I need a structural engineer?

You may be aware of why you need a structural engineering specialist, but do you know when in the process you’ll need them? It’s always best to check whether you need a structural engineer or not at the start – never just assume that you won’t. You can always ask your architect or builder for advice.

Usually, you won’t need to bring a structural engineer on board until after you’ve secured planning permission (if the project needs it). If not, you can hire the engineer at the outset, as soon as you have a project brief. They can work together with the architect to develop the structural design.

First, the engineer will visit the site and check the accuracy of the measurements. Then they’ll provide calculations and design drawings that will then inform the architect’s plans. When the project is ‘tender ready’ they can submit the details to your local Building Control office for approval.

Building Control will inspect construction work during the build, but you can also ask the structural engineer to carry out inspections to confirm their adherence to the approved design. The builder will also use the calculations, drawings, and recommendations by the architect and engineer throughout their work – these will also help to determine the builder’s prices and the timeline for completion.


Where can I find a good structural engineer?

To make sure that you hire someone with the right qualifications and accreditations, you should only hire a structural engineer if they’re a member of the Institute of Structural Engineers (IStructE) or the Institution of Civil Engineers (ICE). Using the ‘find an engineer’ functions on the official websites is much safer than simply typing ‘structural engineers in Wigan’ into Google Search, for example.

Whether you need structural engineers in Liverpool or structural engineers in Manchester, it should be easy to find the details of structural engineering specialists near you. Try to find a structural engineer who specialises in/has plenty of experience with the particular type of structural work you’re doing or service you need (e.g. home extensions, property inspections, or expert witnesses).

If you’re wondering, ‘how much does a structural engineer cost?’, unfortunately, there’s no simple answer to this. The cost will depend on the scale and complexity of the project and the type and extent of services you require. Always ask for a full breakdown of costs for a structural engineering quote, and make sure that the company has professional indemnity insurance before proceeding.