Where do decramastic roofs let water in?
Dented or creased tiles. Metal tiles only take weight in the pan, over the batten, and a step anywhere else can crease one and open a gap. The metal roofing makers' code of practice says a trade who damages tiles, say while fitting an aerial or solar panels, is responsible for the repair.
Rust where the chip has gone. Once the stone chip wears away, the bitumen and then the galvanised steel underneath are exposed. One tile can rust through while its neighbours still look fine.
Flashings, ridges and barges. Where tiles meet a chimney, a wall, a skylight or the ridge, the metal trims carry a lot of water. Loose fixings and gaps here let wind-driven rain in.
How a roofer repairs it
A good roofer traces the leak before touching a tile. Water often shows inside some distance from where it gets in, so expect a look in the ceiling space too.
Then the damaged tiles come out and new ones go in. Gerard says a handful of corroded tiles is usually simple to replace once the cause is known. Decramastic has been superseded by today's pressed steel tiles, so ask what the replacement will be and how it will look on a slope you see from the street.
If the roofer finds white corrosion over large areas, or rust under tile after tile, a patch won't hold for long. Expect them to talk about painting the roof or a re-roof instead, and take that seriously.
Asbestos before any tile comes off
Resene lists Decramastic and early Harvey tiles among the profiles likely to have asbestos in their bitumen coating. Before a roofer cuts, lifts or breaks old tiles, ask whether they'll test a sample or work as if asbestos is present. RANZ gives homeowners the same advice: test old Decramastic before work starts.
If someone else did the damage
Dents that appeared after an aerial or solar install are worth raising with that business first. Note the date of their visit and ask your roofer to describe the damage in writing.
For insurance, the question is whether the damage was sudden. The Insurance Council gives a tree falling on a roof as the kind of damage policies are meant to cover, while rust and wear and tear aren't treated as sudden. More in our guide to insurance and roof leaks.
Your part, and the roofer's
You can
- Put a bucket under any drip and photograph the stain as it grows
- Note whether it leaks in every rain or only in wind from one direction
- Keep any stray tile or granules you find: they help identify the tile
- Ask any tradie recently on the roof to come back and look
Leave to a roofer
- Tracing the leak from the roof and the ceiling space
- Lifting and replacing tiles, ridges, barges and flashings
- Taking an asbestos sample
- Telling you honestly whether repair still makes sense
Our take on decramastic repairs
If the leak is in one spot and the rest of the roof looks solid, we'd fix it and move on. Ask for before and after photos of each tile replaced. If the roofer keeps finding rust every time a tile comes up, that's your signal to get quotes for a recoat or re-roof rather than paying for repair after repair.
Want a roofer to take a look?
Tell us the job and your postcode. We match it with a Find My Roofer certified roofer who specialises in that kind of work, and they call you to quote. Your number goes to them alone.