You will usually need the tenancy details, including the property address, tenancy dates and the parties’ contact information, along with any relevant tenancy agreement. Helpful supporting evidence may include rent payment records, notices, emails or messages, photographs, inspection reports and receipts. Submit the documents relevant to your issue through the RTB’s application process, and keep the originals; the RTB may ask for further information or evidence later. Check the current guidance on the official RTB website, or seek advice from a solicitor if the dispute is complex.