DOT Do I Need a Structural Engineer?
If your job touches a wall, floor or roof that’s holding something up, the answer is almost always yes. Here’s how we work with structural engineers on our jobs, and what they actually do.
How do we work with structural engineers?
On every job with a steel beam or structural change, a structural engineer sets the spec, we build to it, and Building Control sign it off.
We supply one, or you use your own
We have a structural engineer we work with, or if you already have one you’d like to use, that’s fine too.
The engineer sizes the beam
They set the size and thickness of the steel, and the padstones it sits on. The length is just the width of the opening. The size changes from job to job depending on a lot of factors, which is exactly why you need an engineer to work it out.
Building Control sign it off
Once it’s all done, Building Control come out, check the work matches the calculations, and sign it off.
A real example: stronger padstones in Doveridge
On the extension we’re building in Doveridge, a 6m steel runs the whole length of the back wall so the new room can be open plan. The engineer’s spec meant the padstones the beam sits on had to be filled with concrete in the middle for extra strength. It’s the kind of detail you’d never guess without the calculations, and exactly what Building Control check.
When do you need a structural engineer?
Removing a load-bearing wall
To size the steel beam and confirm safe bearing points before Building Control will approve it.
Building an extension
For foundation design, steelwork, and connections to the existing structure.
Converting a loft
To confirm the floor can take the new load, and design any steel needed for the staircase opening.
Dealing with subsidence or cracks
To identify the cause, confirm whether underpinning is needed, and specify the method.
Buying an older or unusual property
A structural survey gives you an independent opinion from a chartered engineer before you commit to buying.
Dealing with a surveyor’s or lender’s concerns
Lenders and solicitors often ask for a structural engineer’s report rather than a general survey.
What’s the difference between a structural engineer, an architect and a surveyor?
| Focus | You need them for | |
|---|---|---|
| Structural Engineer | Safety & stability — beams, foundations, load paths | Any structural alteration; Building Control will need structural calculations |
| Architect | Design & layout of the finished space | Planning drawings and the overall design of an extension or conversion |
| Surveyor | General condition of a property | Pre-purchase condition reports; will refer you to an engineer for structural concerns |
How much does a structural engineer cost?
Typical fees charged by engineers in the Midlands in 2026, not DOT prices. Every engineer prices differently. We can arrange one for you, or you can use your own.
What happens when you use one
For most homeowners it’s quicker and simpler than they expect.
Site visit
The engineer looks at the wall, floor or roof involved, what’s sitting on it, and what it bears onto. For a single beam this is often under an hour.
Calculations
They size the beam, padstones, lintels or foundations and set out how the load is carried. This is the document Building Control checks.
Building Control
The calcs go in with your Building Regulations application. The inspector checks the work on site matches them before signing off.
Sign-off and records
Keep the calculations with your completion certificate. A buyer’s solicitor will ask for both when you come to sell.
Questions worth asking an engineer
Whether you hire one yourself or we arrange it, these are good things to check.
Are you chartered?
Look for MIStructE or MICE after their name, or a CEng qualification. It’s a quick way to check they’re properly qualified. Ask to see their insurance too.
Is a site visit included?
Some quotes are desk-based only. For older houses, or anything with cracks, a visit is worth paying for.
Will the calcs go straight to Building Control?
Ideally yes. It saves a round of questions and keeps the job moving.
Common questions
What people ask us most about structural engineers.
Is a structural engineer a legal requirement?
Not directly. The law requires structural work to meet the Building Regulations. In practice, Building Control will ask for structural calculations for things like beams, new openings and foundations, and those come from a structural engineer.
Can my builder do the calculations instead?
Not usually. Builders install the work; the design and calculations should come from a qualified engineer. We arrange the engineer for you as part of every structural job we quote.
How long do calculations take?
Often one to two weeks for a single beam, depending on how busy engineers are. Larger packages for lofts and extensions can take a little longer.
Do I need one for a non-load-bearing wall?
No, but someone needs to confirm the wall really isn’t load-bearing. Joists running on top of it, or a wall directly above it, are warning signs. If in doubt, get it checked before anything comes out.
Not sure if your project needs one?
Tell us what you’re planning and we’ll give you a straight answer, free of charge.
Call 01889 725765 Ask Us