4191 Ancillary items (17) 4197 Cleaning, repairing and renovating existing tanking, damp-proofing and underlays (3) Cutting out, cleaning, repairing and renovating existing tanking and damp-proofing 4198 Alteration work; demolishing and reconstructing tanking, damp-proofing and underlays (0) Demolishing and reconstructing tanking and damp-proofing as part of general demolition, reconstruction, alterations and additions