Because the Landlord owns the building and will own the property when your Lease ends the Landlord needs to ensure that you do not make alterations or additions which may adversely affect the Landlord or damage the building. Some alterations or additions do not require the Landlord’s permission. For example, internal painting and decorating, minor plumbing and electrical works, upgrading of kitchens and bathrooms on a like-for-like basis and new interior doors do not require the Landlord’s permission. If you are thinking of making any other alterations or additions you should ask the Landlord for permission before you carry out any work. If work has been carried out already without the Landlord’s permission, you should ask the Landlord for what is called retrospective permission. Alterations and Permissions Factsheet and Form.