Large-span warehouse and factory roofs behave differently to the smaller pitched roofs found on Victorian terraces, and Collingwood has plenty of both. Converted industrial buildings often have long, low-pitch metal roofs that were built for function rather than weathertightness over the long term, and once these buildings are repurposed into apartments or commercial space, any existing roofing issues become a lot more consequential, since a leak that once dripped into an empty warehouse now affects a fitted-out home or business. On the residential side, Collingwood’s older terraces frequently have roofs that have absorbed years of minor, uncoordinated repairs, which tends to leave weak points at flashing junctions and old penetrations that were never properly resealed. We approach each type differently, because treating a converted warehouse roof the same way as a terrace roof, or vice versa, generally leads to the wrong fix.