Start indoors and stay safe.
Take one photograph showing the room and another showing the damp patch. Record the date and whether the affected area grows after further rain. Move vulnerable belongings if safe. Do not climb onto a wet roof or use a ladder to photograph an awkward detail. If there is immediate danger, contact appropriate emergency assistance.
Tell us about your situation ↗Conditions can help narrow the question.
Does it happen during every shower or only with wind from one direction? What is above the mark: a flat roof, window, gutter or pitched section? Previous repairs and recently installed roof components may also matter. Report observations rather than trying to diagnose the failed junction yourself.
Send a defined enquiry.
Include your postcode, building type and whether you are the owner, tenant or VvE contact. Mention access to the attic and whether a visit requires entry through an apartment. WhatsApp can carry photographs; avoid including identity documents or unnecessary personal details. Remote information helps prepare an inspection but cannot replace one.