Why Wellington Houses Get Moss and Mould So Fast

Wellington is wet, windy and close to the sea. Mould on weatherboard and moss on roofs are not a one-off — they are the climate.

North walls: They stay damp after rain. Green streaks under eaves are the first sign.

Salt: Harbour and Strait suburbs collect film that holds moisture against paint. Seatoun, Miramar and Petone show it earlier than Karori.

Shade and trees: Ngaio, Tawa and Pinehaven keep walls wet for days. Gutters overflow and soak the same elevation.

What works: Soft wash on cladding. Biocide spray-and-leave on roofs — not a blast that strips Colorsteel. Washing every 12–18 months is cheaper than repainting early.