Keep a clear evidence trail
Retain invoices, guarantees, building-control records and product information that clearly identifies the property and work completed. Evidence is particularly useful when an improvement is concealed and cannot be confirmed visually.
Reassessment is not automatic
Improvement work does not automatically update an existing certificate. Consider a new assessment when a current certificate is needed for sale or letting, or when an updated rating has a clear practical value.
Editorial boundary
This guide provides general orientation and links to official sources. It is not legal advice, a property-specific assessment, a building survey or a retrofit design.