Working with a structural engineer — what to expect

If you've never worked with a structural engineer before, it can feel like a bit of an unknown. What do they actually do? What will they need from you? How long does it take? And how does it all fit in with everything else going on with your project?

Here's a straightforward guide to the process — from first contact through to completion.

First Contact — What to Tell Us

The earlier you get a structural engineer involved, the better. Ideally before you've finalised designs or committed to a builder, because structural requirements can influence both.

When you first get in touch, the more information you can give us the better. You don't need to have everything pinned down, but it helps to know:

The existing structure — walls, floors, roof, foundations where relevant

• What you're planning to do — extension, loft conversion, wall removal, etc.

• The approximate size and scope of the project

• Whether you have an architect involved or are working directly with a builder

• Whether planning permission has been applied for or granted

• The age and general construction type of the property if you know it

Even if you're at an early stage and just want to understand what's involved, a quick conversation can save you time and money down the line. We're happy to have that conversation before any commitment is made.

The Site Visit

For most residential projects, we'll arrange a site visit before producing any calculations or drawings. This gives us the opportunity to assess the existing structure first hand — something that drawings alone often can't tell you.

During the visit we'll typically look at:

• The existing structure — walls, floors, roof, foundations where relevant

• The proposed works and how they interact with the existing building

• Any obvious issues that might affect the design — previous alterations, movement, condition of the structure

• Single and double storey extensions — spanning over new openings in the existing structure

• Access and practical constraints for the build

It usually takes an hour or so depending on the complexity of the project. We'll ask questions, take measurements and photos, and leave with a clear picture of what's needed.

A site visit isn't just due diligence — it's where good engineering starts. You can't design something properly without understanding what's already there.

The Design and Calculation Stage

Once we've got all the information we need, we'll work up the structural design. This involves:

• Structural calculations — working out the loads, checking the capacity of existing elements, sizing new ones

• Structural drawings — clear, dimensioned drawings showing what needs to be built and how

• Specification notes — details of materials, connections, padstones, temporary propping requirements

The level of detail depends on the complexity of the project. A straightforward beam over a single opening is a relatively quick exercise. A loft conversion with a new floor structure, ridge beam and altered roof geometry takes considerably more work.

We'll keep you informed of progress and flag anything unexpected as it comes up. If something changes the scope or the cost, we'll tell you before we proceed, not after.

Building Regulations and Building Control

Structural calculations and drawings form part of your building regulations submission. Building control — either the local authority or an approved inspector — will review the structural information as part of their approval process.

We produce our calculations and drawings to the standard required for building regulations submission. If building control have queries or require additional information, we'll deal with those directly.

One thing worth knowing: building regulations approval and planning permission are separate processes. You can have one without the other. Most structural work requires building regulations approval even if it doesn't need planning permission.

Building control sign-off isn't just a legal requirement — it's your assurance that the work has been independently checked and is safe. Don't skip it.

Working With Your Builder

Our drawings are produced to be used on site. That means clear dimensions, details at the critical junctions, and enough information for an experienced builder to price and carry out the work without having to guess.

During the build, questions come up — they always do. We're available to answer queries from your builder as the work progresses. If something on site doesn't match what's on the drawings, we'd rather know about it early than find out when it's caused a problem.

Common things that come up during construction:

• Unexpected ground conditions when foundations are opened up

• Existing structure that doesn't match what was expected — particularly in older properties

• Changes to the scope requested by the client mid-build

• Queries about temporary propping or sequencing of structural works

We deal with these as part of the job. Structural engineering on a live residential project isn't just about producing drawings — it's about supporting the build through to completion.

Inspections and Sign-Off

Depending on the project and the building control route, there may be structural inspections required at key stages — foundations, steelwork installation, structural connections. Building control will advise on what's needed for your specific project.

We can carry out structural inspections on your behalf if required, and produce inspection reports confirming that the works have been carried out in accordance with the structural design.

At the end of the project, building control will issue a completion certificate confirming that the building regulations requirements have been met. Keep this — you'll need it when you come to sell the property.

How Long Does It All Take?

Timescales vary depending on the complexity of the project and how busy everyone is, but as a rough guide for a typical residential project:

• Initial enquiry to site visit — usually within a week or two

• Calculations and drawings — typically two to three weeks from site visit for a straightforward project

• Building control review — can take several weeks depending on the authority and submission route

• Construction — varies enormously depending on the scope of works

The earlier you get a structural engineer involved, the less likely it is that the structural process will hold up the build programme. Last-minute appointments — when the builder is on site ready to knock walls down — don't give anyone enough time to do the job properly.

What Should I Look For in a Structural Engineer?

A few things are worth checking before you appoint anyone:

• Membership of the Institution of Structural Engineers (IStructE) — recognised members have demonstrated the competence and experience required to practise as a structural engineer in the UK

• Relevant residential experience — structural engineering covers a wide range of project types, and you want someone who has experience working with houses

• Professional indemnity insurance — essential for any design professional

• Clear communication — you should be able to understand what they're telling you, and they should be willing to explain things clearly and in layman terms if required

Don't be afraid to ask questions. A good structural engineer will welcome them.

The best structural engineers aren't just technically competent — they communicate clearly, flag problems early, and make your project easier, not harder.

Ready to Get Started?

At Structural Productions, we work with homeowners, self-builders and architects on residential projects across South Wales and the Southwest. From initial enquiry through to building regulations sign-off, we provide clear, practical structural engineering support at every stage.

If you've got a project in mind and want to understand what's involved, get in touch. We're happy to have an initial conversation at no obligation.