What clay tiles are
Clay tiles are fired terracotta. Level says most of New Zealand's are imported from across the Tasman, with Italian, Spanish and Asian tiles also available. Monier's range here is flat Urban Shingle, semi-flat Noveau and the raised Marseille.
The Marseille pattern has a long history here: Gisborne's Singer House, built in 1913, wears Marseilles tiles. A Monier Marseille tile today weighs 3.75 kg, with about 13 to the square metre.
Clay or concrete?
| Clay (terracotta) | Concrete | |
|---|---|---|
| Colour | Monier warrants terracotta colour for 30 years | A surface coat that fades, Monier says |
| Painting | Generally not; unglazed tiles can be, but then need recoating | Optional and cosmetic |
| Expected life | 50+ years (Level) | Warranted against defects for 30 years (Monier) |
| Weight, Monier examples | 47.25 kg per square metre (Marseille) | 57.2 kg per square metre (Horizon) |
| Other traits | Won't burn, and inert enough for collecting rainwater (Level) | Turns porous once weathered and grows moss readily (Resene) |
Where they suit in New Zealand
Clay asks a lot of the house. Level says it needs more substantial framing and bracing than lightweight roofing, so it suits homes built for it.
In a quake, tie-downs are what count. The Canterbury earthquakes showed it: BRANZ found tiles on hill-suburb roofs often shook loose where they'd never been tied to the battens, or the ties had rusted. In shaky country, ask a roofer to check yours.
On the coast, the clay itself copes, but E2/AS1 wants 304 or 316 stainless fixings in any zone, with hot-dip galvanised only acceptable in Zones B and C. Glazed tiles also count as an inert surface, and NZ Steel warns that water running off one can cause drip-spot corrosion on bare galvanised spouting below.
In the windiest places, E2/AS1 requires underlay under any tile roof, in Very High or Extra High wind zones.
Repairs and re-using tiles
Level says clay tiles can readily be re-used if they're taken off carefully, but to expect breakage losses of up to 30%. That's handy for repairs, because a roofer with salvaged tiles may match yours better than anything new.
Monier says terracotta generally shouldn't be painted. Unglazed tiles can be, but you're then signing up for ongoing recoating.
Going lighter is MBIE's own example of consent-exempt work: replacing an old clay tile roof with longrun or pressed metal tiles in the same position, while considering the higher uplift forces. You're still responsible for deciding it's exempt, so check with your council if you're unsure.
Looking after them
Monier suggests the roof is checked and cleaned at least once a year, twice under trees, with an expert inspection every five to seven years. Level says lichens and mosses grow on damp, weathered clay. That cleaning is for a roofer or roof-cleaning specialist without a pressure washer, since Monier strongly advises against them.
Consumer NZ says anyone who must walk on clay tiles should wear soft-soled shoes with good grip and step only on the tiles' front edge. That's the roofer's job, not yours.
Questions for the roofer
- Can you match my tiles, new or salvaged?
- Are my tiles tied down, and are the ties corroded?
- Does the ridge need rebedding or repointing, and with what?
- How will you move around without cracking tiles?
Your part
You can
- Spot slipped, cracked or missing tiles from the ground with binoculars
- Look for daylight or drips in the roof space after heavy rain
- Store any spare tiles flat and dry
Leave to a roofer
- Replacing broken tiles and refixing slipped ones
- Ridge bedding and pointing
- Moss and lichen treatment
- Checking ties and underlay
Our view on clay
A sound clay roof is worth keeping, and we'd spend on the ridges and fixings before thinking about anything bigger. In a quake-prone area, we'd have the tie-downs checked first. Swapping to metal only makes sense to us when the framing is struggling or tiles are breaking faster than they can be replaced.
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.