Roofing is the trade New South Wales splits across three licence categories, none of which is specialist work. The Home Building Regulation 2014 cl 13(b) lists roof plumbing, roof tiling and roof slating as trade categories of residential building work; the register names them Roof Plumber, Roof Tiler and Roof Slater — the labels the badges here quote. The split matters: the Act writes roof plumbing out of specialist work in terms — the definition reads "plumbing and drainage work, other than roof plumbing work". So a roof is licensed once labour and materials pass $5,000, the ordinary building threshold, not at any value the way indoor plumbing is.
Roof drainage is the part of the Central Coast job the weather actually sizes. Norah Head, the coast's long-record station (Bureau of Meteorology site 061366, 1995–2026), averages 1,215.2mm of rain a year across 99.2 days of 1mm or more — rain that arrives often rather than rarely, which is a gutter, downpipe and flashing question before it is a roof-covering one. That is precisely the scope of the roof plumbing category: the Act defines roof plumbing work as fixing, installing, renovating, altering, repairing and maintaining "guttering, downpipes, roof flashing and roof coverings", while carving out coverings made of non-metallic tiles and slates, glass, concrete, timber, thatching and bituminous membrane. Tiled and slate roofs therefore belong to the roof tiling and roof slating categories instead. In a strata block, the statutory Common Property Memorandum puts guttering and membranes on the owners corporation's side — but only where the building's by-laws have adopted it.