Section 20 major works are large-scale maintenance, repair, or improvement projects carried out on residential buildings where individual leaseholders may be required to contribute more than £250 through the service charge. Under the Landlord and Tenant Act 1985, landlords and managing agents must usually follow a formal consultation process before undertaking these works.

The Section 20 consultation process is a legal requirement that landlords and managing agents must usually follow before carrying out major works where leaseholders will contribute more than £250 through the service charge. The process typically consists of three stages: the Notice of Intention, Statement of Estimates, and Notice of Reasons.