The seller should request that their building owner or managing agent commissions an EWS1 assessment where their building is in scope. The building owner or managing agent is responsible for confirming what materials are on their building and whether an assessment is required.
The building owner should have a valid EWS1 form for the building to confirm that the external wall cladding system has been assessed by a suitable expert. A valuer or lender will also ask for an EWS1 form if they suspect an external wall cladding system may contain combustible materials for buildings in scope.