Building control services check that building work complies with the relevant building regulations and technical standards. Customers may use a local authority building control service or, where permitted, a private building control provider. These services commonly deal with new buildings, extensions, structural alterations, changes of use and other work that affects a building's safety or performance. Building control approval is separate from planning permission, and not all work requires the same level of approval. Services typically include reviewing plans and specifications, advising on regulatory requirements and carrying out inspections at key stages of construction. Checks may cover structural stability, fire safety, insulation and energy efficiency, ventilation, drainage, sanitation and access. Once work is complete, the building control body may issue a completion certificate if it is satisfied that the work meets the applicable requirements.