Clay and concrete tile

Typical lifespan

50–100 years

Installed cost per square

$1000–$2500estimate

Weight

600–1,200 lb per square

Fire class

Class A

Impact class

Brittle — tile cracks under foot traffic and large hail

How does clay and concrete tile actually work?

Tile does not really waterproof a roof; it shelters the thing that does. Individual tiles are hung or fastened over a waterproof underlayment, and they shed the bulk of the water, break the sun and take the weather — but the layer actually keeping water out of the house is the membrane underneath. That single fact explains the whole ownership pattern: the tile lasts fifty to a hundred years, the underlayment lasts twenty to thirty, and a tile roof is therefore usually stripped, re-underlaid and re-laid with the same tiles rather than replaced. Clay is fired earth and holds colour essentially forever because the colour is the material. Concrete tile is cast and pigmented, costs less, weighs a little more, and fades.

What drives the cost?

Weight is the first cost, and it can be a structural one: tile runs three to five times the weight of asphalt, so converting to it requires an engineer's evaluation and sometimes framing work before a single tile is ordered. After that, the drivers are the tile profile, the complexity of the roof, and the skill premium — tile is a specialist trade and the pool of crews who do it properly is smaller than for asphalt. Budget also for the fact that the expensive future event is not replacement but the re-underlayment cycle, which involves carefully removing and stacking every tile and putting it back.

What separates a good installation from a bad one?

The underlayment specification matters more on a tile roof than on any other covering, because it is doing the waterproofing and because replacing it is a major job. Attachment method has to suit the wind zone — in high-velocity hurricane zones this is prescriptive and inspected. Flashings at valleys, walls and chimneys need to be generously sized and formed for the tile profile, since water moves in volume under the tiles rather than over them. And battens, where used, must not dam water: a batten laid solid across the slope turns into a small weir every time it rains.

Where does clay and concrete tile work well?

Best climates: Hot, dry and coastal southwest; Mediterranean and Spanish-influenced architecture

Worst climates: Hard freeze-thaw cycling, which spalls concrete tile and cracks clay

What maintenance does it need?

The main discipline is to stay off it. Tile breaks under foot traffic, and most broken tiles on a roof were broken by someone walking on it — a satellite installer, a chimney sweep, a painter. When work does need doing up there, it should be done by someone who knows where the load-bearing points are. Beyond that: keep valleys clear, replace cracked tiles promptly because each one exposes the underlayment to UV, and plan the re-underlayment before it announces itself with a leak.

What fails first

The underlayment, invisibly, long before the tile shows anything. Then broken tiles from foot traffic

When should you choose it?

Choose tile in hot, dry and coastal southwestern climates, where it performs beautifully and looks like it belongs. Choose it if you are staying long enough for a fifty-to-hundred-year covering to mean something, and if the structure either already carries tile or can be made to. It is also a strong answer in wildfire-exposed areas, where a Class A non-combustible covering is doing real work.

When should you think twice?

Avoid tile where hard freeze-thaw cycling is normal: it spalls concrete tile and cracks clay, and no installation quality prevents it. Avoid it on a structure that has not been evaluated, and treat any contractor willing to skip that evaluation as a warning about everything else they will skip. And think twice on a roof that needs regular access for equipment, because every visit is a tile-breaking opportunity.

What ratings does it carry?

Common mistakes

• Converting to tile without a structural evaluation. It weighs three to five times what asphalt does, and any contractor willing to skip that check is telling you what else they will skip.
• Treating the tile as the waterproofing. The underlayment is what keeps water out, and it is the component that will need replacing first.
• Letting tradespeople walk the roof. Most broken tiles were broken by a satellite installer, a sweep or a painter rather than by weather.
• Specifying a cheap underlayment. It is the expensive thing to replace, so saving on it front-loads a much larger bill.
• Leaving cracked tiles in place. Each one exposes the membrane below to UV, which is exactly what shortens the part you cannot see.