The local authority have the power to inspect new buildings and those with extensions which required planning, their role is to ensure that the building meets all the requirements of the grant of planning permission. The responsibility is not just on the owner but also on the builder, engineer or design consultant engaged by the owner.
If you are concerned then this visit could be a very good opportunity to get heads together and get proper certification or call out issues.
Just to clarify, a BCO will not check that the works meet all the requirements of the Planning Permission, in fact, they don't care if its pink, blue or yellow, or bigger, smaller than the grant as long as its in compliance with the Building Regulations.
This will involve Commencement Notice, Structure, Fire Safety, Moisture, Ventilation, Drainage etc
Technical Guidance Documents Part A to M will guide you further.
The Building Control Acts 1990 to 2014 vest the powers of inspection, enforcement and prosecution in the 31 Local Authorities. Authorised officers of each local Building Control Authority have delegated powers to:
- scrutinise proposals and inspect works in progress;
- serve enforcement notices on owners and builders for non-compliance;
- institute proceedings for breaches of any requirements outlined in the Acts, or any regulations made thereunder;
- seek High Court orders to mitigate danger to the public where serious non-compliance poses risks to public safety.
Failure by an owner or a builder, at the request of a Building Control Authority, to demonstrate compliance with Building Regulations or Building Control Regulations, or to rectify such non-compliance, may be an offence under the Building Control Acts. If successfully prosecuted in court, such offences may lead to a fine and/or a term of imprisonment.