Most homeowners never see a structural calculation directly — it passes between the engineer, the builder and building control without much need for the client to read it. That's normal, but it also means the one area where a shortcut is easiest to take invisibly, if a builder is inclined to take one, is exactly the area you're least likely to notice.
A short set of questions closes that gap without needing to understand the engineering itself.
Ask to see the calculations exist, not just that an engineer was 'involved'
Being told 'an engineer looked at it' is not the same as having a dated set of calculations and drawings for the specific beam or structure being installed. Ask for a copy, even if you can't interpret the technical content yourself — the existence of a proper document, referencing your address and the specific opening, is what matters.
If the answer is that calculations will be 'sorted before building control ask for them', that's a sign the sequence has been reversed — the calculations should exist before the structural work is built, not produced afterward to satisfy an inspection.
Check the beam size matches the drawing, physically
If you're comfortable doing so, or with someone who can, check the actual steel or timber beam installed on site matches the size and specification on the engineer's drawing — this is a straightforward physical check once the beam is visible, before it's boxed in. Discrepancies do happen, sometimes due to supplier substitution, and catching it before it's covered is far easier than after.
Ask specifically whether the beam was installed exactly as drawn, or whether any substitution was made and, if so, whether the engineer approved it.
Confirm padstone and bearing details were actually followed
These are the details most likely to get simplified on site under time pressure, because they're less visible than the beam itself. Ask whether the padstones specified on the drawing were the ones installed, in the sizes stated, and whether this was confirmed by the engineer's own site visit rather than just by the builder's word.
If the wall the beam bears onto turned out to be in worse condition than expected once exposed, ask whether the engineer was informed and whether the design was adjusted in response.
Check when the engineer actually visited site
Ask for the dates of any site inspections carried out by the engineer, and what they were checking at each visit. An engineer who never physically inspected the finished structural work, on a job involving significant structural change, is relying entirely on the builder's own account of what was constructed.
Where a certificate of structural adequacy is being provided, confirm it's based on an actual inspection rather than issued from the original calculations alone without ever checking the completed work.
Get the final paperwork before releasing final payment
Before final payment, confirm you have copies of the calculations, the engineer's drawings as actually built (with any revisions marked), and any certificate issued. These should sit alongside your building regulations completion certificate, since a future buyer's solicitor or surveyor is likely to ask for exactly this evidence.
If any of this paperwork is missing at completion, it's far easier to get it resolved before the final invoice is paid than to chase it afterward once there's no financial leverage left.
Common questions
Can I use a different structural engineer to the one my builder usually works with?+
Yes — you're entitled to appoint your own engineer independently, which some homeowners prefer on larger projects specifically to keep design and construction checks separate.
What if there's no visible beam because it's within a timber floor structure?+
Ask to see the relevant section before it's boarded over, or ask the engineer to confirm in writing after their own inspection that it was installed as specified, since you may not get another chance to check it visually once it's covered.
Is a verbal confirmation from the engineer good enough?+
No — get anything confirming compliance in writing, even briefly by email, since a verbal assurance carries no weight if a dispute or a future sale query arises.
Ask us how structural sign-off is managed on your job
We'll show you the calculations, the site inspection record, and the final sign-off in writing before you pay a final invoice.