Roofing materialsStart with what's on your roof now.

Not sure what you've got?

From the ground, longrun looks like long sheets with waves or ribs running from ridge to spouting. Coloured sheets are usually pre-painted steel such as COLORSTEEL; plain silver or dull grey ones are ZINCALUME or galvanised iron. The longrun profiles page helps you name the shape.

Small metal tiles with a gritty stone-chip surface are decramastic or pressed metal tiles. Chunkier overlapping tiles are concrete or clay. Flat roofs and decks over rooms are usually a membrane such as Butynol.

Grey cement sheeting, especially the deep corrugated kind, may be asbestos cement. WorkSafe says any home built before 2000 may contain asbestos, so read that page before anyone cleans, drills or cuts it.

Where you live changes the answer

Salt is the big one for metal. NZ Steel sets its warranties by distance from the coast, while the Building Code's Acceptable Solution uses separate NZS 3604 exposure zones, so a roofer should check both for your address. Geothermal ground, like much of Rotorua, is hard on metal too.

In earthquake country, weight counts: the Natural Hazards Commission suggests lighter roofing in place of heavy concrete or slate tiles. Wind and snow mostly change the profile, fixings and spouting rather than the material itself.

Changing or refreshing a roof

Thinking about a recoat? Roof paint sets out which system suits which roof. Planning a re-roof? Roof underlay covers the layer you only replace when the roofing is off, and how long a roof lasts puts your roof's age in context. For a pergola or carport, see polycarbonate roofing.

When you'd like a roofer's eyes on it, tell us about the job and we'll pass it to one checked local roofer.