I have recently had a first floor rear extension completed and the building regulator has requested the following: • A copy of the structural engineers drawings and calculations are required, the engineer's accreditation details should be on the head of each page. • Clarification is required on the insulation build-up to the roof and walls, a confirmation of the achieved u-value is required. • Confirmation required whether the roof is a warm or cold deck roof design. I already have the drawings and calculations from a structural engineer I used but his accreditation details are missing.