Separate observation from responsibility
A mark below another flat suggests a route to investigate; it does not establish liability or the precise source.
Arrange access together
Identify the owners, occupants and managing agent who can authorise entry and isolation. Explain any shared services.
Keep one clear history
Combine the sequence of symptoms and earlier work into a single record. It helps avoid different assumptions across properties.
Explore the relevant service
General information for planning an investigation. The property, instruction and findings determine the appropriate work.