Dear __________ (mention),
This email is to state that room number ___________ (mention room number) shall be kept close/ inaccessible for coming ___________ (mention duration – number of days/ week/ any other). It is to request you all to kindly prevent going to the mentioned room for the said duration as the room mentioned will be under maintenance.
It is to request you kindly consider this as a genuine request. In case of help, please reach out at __________ (reception area/ desk area) for further clarification.
[Digital Signature – if applicable]
____________ (Contact details)