Having minor works done - what order

longwalks1

we we are going to open up the rear ground floor of the house, removing a 2.8m gap (currently back door and rear kitchen window) and fit bifold doors. Had structural engineer round to do the calcs and awaiting a price from a builder.
At what point do we let building control know?  And when do they inspect? Before, during, or just after the works? 

And do BC have to approve the engineers calcs? 

Many thanks 

FaceHead

Appoint a building inspector well before works begin. They need to give the local authority notice (I think 5 days). Yes, they also review the plans and structural design to ensure it conforms, so again, you want to be appointing them and giving them the plans well in advance, so they can flag any howlers before work beings. 

Give their details to the builder, and the builder will call the building controller and get them to inspect at the right times: before/near commencement, when the foundations are dug etc. If you have a good builder and a good building controller they will sort themselves out and you won't interact with building control much at all.