4494 Membrane roof vents (0) Roof vents fixed into membrane roofing 4495 Membrane Accessories (13) Membrane accessories proprietary or preformed 4497 Cleaning, repairing and renovating existing membrane roofing (3) Cutting out, cleaning, repairing and renovating existing membrane roofing 4498 Alteration work; demolishing and reconstructing membrane roofing (0) Demolishing and reconstructing membrane roofing as a part of general demolition, reconstruction, alterations and additions