Retrospective signoff building control?

[haremscarem55]

Looking for some advice on building control signoff.

In 2019 we had a single storey rear extension. The builders had a private building control company come in at each stage but then Covid hit before the job was finished (things like the skirting boards and snag list were due to be done in march and didn’t happen until summer of 2020). With everything, I’d not realised we didn’t have building signoff until last year when we got an email from the private inspectors out of the blue, and then within a month they’d gone bust, the case referred back to local authority.

Looking for advice on if / how we can get retrospective signoff / what the process is. If the builder has paperwork & photos would they form part of the assessment? Would it be a structural review?

Grateful for any advice on what that process might look like.

Invite BC around
Give them all paperwork you have. Ask the builders for everything they have. This should include structural calcs for foundations, lintels etc. Fensa certificates for windows and glazed doors, Uvalue calcs ( or at the very least wall, roof and floor details indicating thickness of insulation and air gap ).
Photos of work as it progressed are a life saver in these situations

BC will walk around
If they don’t have enough evidence they may ask for certain areas to be opened up. So they may ask to inspect the foundations and a hole will need to be dug. They may ask to look at the roof construction, wall construction etc.
If you’ve got photos of these areas they may be satisfied that that’s enough.

They then either don’t approve the works and will tell you what to do to upgrade
or
They do approve it and issue you a building regs cert.

Thank you so much @DrPrunesqualer for the clear plan of attack. I've literally been having panic attacks about this. Really appreciate your taking the time to reply.

I had the same situation. Cost me around £350 to submit a 'reversion application' to the council (Cornwall Council). The inspector came out and looked through the drawings and calculations I had kept. He wanted to see an electrical safety certificate and HETAs certificate for the woodburner and that was it, all signed off!

Like you I was worried they'd be digging inspection holes allover the place, but it was absolutely fine :)

There’s no need to worry about this.
Building Control are very supportive and very used to these situations.
They don’t expect home owners to know anything and will give you all the advice you need.
Good luck