Coatings & Corrosion

In January 2019 I was asked to look at a house in Tikipunga on the northern edge of Whangarei, where the owners were convinced the roof was leaking. A brown stain was spreading across the hallway ceiling and no rain had fallen for nine days. I went into the roof space at 2 pm with

The roof in Woolston was twenty-two years old, a pale grey Zincalume corrugate on a 1960s brick bungalow two streets back from the Heathcote River, and from the footpath it looked fine. I was there in October 2022 because the owner wanted it painted. From the ladder the story changed. Along the bottom edge of

In March 2023 I was sent to a house in Devonport, about 300 metres from Cheltenham Beach, to look at a repaint that had lifted after eighteen months. The product was one I had supplied. I could peel the topcoat off in strips 200 mm wide with my fingers. Underneath was the chalked surface, and

My parents retired to Castlecliff in 2004 and had the old bungalow on Rangiora Street re-roofed in Zincalume long-run the same year, unpainted, because the roofer said it would see them out. In February 2024, twenty years on almost to the month, I went up with a camera and a screwdriver to see how it

In spring 2019 I helped my brother-in-law repaint the Zincalume roof on his garage in Ilam, just off Clyde Road. We waterblasted it, let it dry for a day, and rolled on two coats of a good-quality acrylic straight from the tin. Eighteen months later the paint was lifting in sheets you could peel with

A 1926 bungalow on Grey Street in Hamilton East taught me the cost of doing an exterior repaint in the wrong order. In 2019 the owners had the weatherboards painted in November, a good job, three coats. In February they had the roof washed and painted. The wash brought forty years of chalk, lichen and

In March 2023 I stood on a 1974 long-run roof in Mount Roskill, ran my palm along a sheet of what had once been Karaka green Colorsteel, and it came away white. The owner already had two quotes. One said wash and paint, three days, done. The other was nearly double and included a line