Roofs of traditional Japanese buildings, such as shrines and temples, are often covered with tiled roofs.This type of roof is known as kawara-yane 瓦屋根 in Japanese.
1. What is kawara
Kawara is a variety of clay tile. The term originally refers to a slab of clay that has been baked until it hardens. The notion of clay, together with clay roofs, were passed on from China around the 7th century.
Due to their fire resistant and good ventilation features, clay tiles were always well suited to the Japanese climate. Their usage in construction soon spread throughout the country.
Most conventional kawara is ceramic made of dark gray clay, but it is very heavy.
2. New titanium kawara
The nation’s biggest steelmaker has developed a “kawara” roof tile made of titanium in early 2000. Titanium kawara are much stronger and lighter than the old-style version, helping a structure stand up to a strong earthquake.
A titanium kawara measuring 20 cm by 22 cm weighs only 90 grams, about 1/10 of a conventional tile. The price is about three times higher, but the titanium kawara's superior durability means maintenance costs are a lot lower.
3. Sensoji temple covered with the titanium kawara
Sensoji Temple in Asakusa of Tokyo has adopted the titanium product to cover the roof of its main hall. “You can’t tell the difference in appearance when you look at them from a distance,” a temple employee says.
The temple first used titanium kawara to repair a temple gate in 2007 out of concern that the heavier conventional roof tiles could be shaken loose by an earthquake and injure visitors.
When you visit a temple or a shrine, it would be interesting to see whether its roofs are covered with conventional kawara or new titanium kawara.
(1) KYODO NEWS (MAY 25, 2009) ARTICLE “Nippon Steel pitches roof tiles made of titanium”
(2) Macha (https://matcha-jp.com/en/886) "Kawara" (Clay Roof Tiles) 2016.05