Glazed Tiles: The Golden Roofs of China

The roofs of traditional Chinese buildings are among the most recognizable silhouettes in world architecture — long, sweeping eaves that turn upward at the corners, and a shimmering skin of ceramic tiles. At the summit of this craft stands the glazed tile (琉璃瓦, liúlí wǎ), a vitreous ceramic roofing material perfected over fifteen centuries. The golden roofs of the Forbidden City, the green roofs of princely mansions, and the deep blue roofs of the Temple of Heaven announce, at a glance, the rank and purpose of each building. Glazed tile is therefore not merely a waterproofing; it is a coded language of color, hierarchy, and cosmic order written across the Chinese skyline.

What Is a Glazed Tile?

A glazed tile is a clay tile coated with a glassy lead-silicate glaze and fired so that the surface fuses into a hard, impermeable, light-reflecting skin. The glaze both protects the porous clay body from frost and rain and gives the roof its color. Because the glaze is colored with metal oxides, a single kiln could produce a range of hues from the same basic material. The result is a roofing that is at once practical and ceremonial — it sheds water for centuries while broadcasting the status of the building beneath it.

A Long History: From Han Green to Ming Yellow

Glazed ceramics in China reach back to the Shang and Zhou, but architectural glazed roofing emerged in force during the Han, when green-glazed tiles using copper oxide appeared. The Tang developed the three-color (sancai) palette and expanded blue and yellow glazes. By the Yuan and Ming, dedicated imperial kilns — above all the Liuli workshops at Liuliqü in Beijing's Mentougou district — supplied the vast roofscapes of the capital. The Ming and Qing turned glazed tile into an instrument of state, with yellow reserved for the throne and a strict code governing every other color.

How Glazed Tiles Are Made

Production begins with a carefully selected clay, shaped and given a "biscuit" firing at high temperature. The tile is then dipped or brushed with a glaze made of ground lead glass mixed with metal oxides — iron for yellow, copper for green, cobalt for blue, manganese for purple or black. A second firing at roughly 800–900°C melts the glaze into a smooth, glassy coat. The two-stage process is demanding: a flaw in either firing can ruin the piece, and matching a color across a whole roof required tight control of the kiln atmosphere.

The Tile Family: Tongwa, Banwa, Wadang, Dishui

A Chinese tiled roof is built from several standard shapes. The tǒngwǎ (筒瓦, "tube tile") is a half-cylinder laid convex-side-up to shed water; the bǎnwǎ (板瓦, "board tile") is a broad concave tile laid beneath it. At the eave's edge, round wǎdāng (瓦当, "eave-end tiles") are stamped with auspicious motifs, and dīshuǐ (滴水, "drip tiles") have a downward lip that throws rainwater clear of the wall. Ridge and corner tiles complete the set, so a single hall may use a dozen distinct molded forms in a coordinated design.

The Language of Color

Color on a glazed roof was a legal code as much as a decoration. Yellow was the exclusive color of the emperor and his closest temples; green marked princes, nobles, and many Buddhist monasteries; blue or azure symbolized heaven and crowned the Temple of Heaven; black, associated with water, was used on libraries and some gates as a charm against fire; and purple — the rarest and most costly, made with manganese — was reserved for the most sacred structures. Unauthorized use of yellow tile could carry grave punishment, so the roof color let any viewer read the building's place in the hierarchy.

Yellow for the Son of Heaven

Nowhere is the color code clearer than in the Forbidden City, whose yellow roofs declare the resident's unique status as the Son of Heaven. The same imperial yellow was granted to a handful of specially favored sites, such as the Confucius Temple at Qufu and certain imperially endorsed monasteries, as a mark of honor. The visual effect is staggering: from the coal hills to the meridian gates, a sea of gold tile unifies hundreds of buildings into a single assertion of supremacy. Yellow glaze thus became the chromatic signature of the Chinese empire itself.

Ridge Beasts and the Chiwen

The ridges of a glazed roof are crowded with ceramic creatures. A procession of small figurines — led by an immortal riding a phoenix and followed by the dragon, phoenix, lion, seahorse, heavenly horse, and others — ranks the building, the Hall of Supreme Harmony carrying the maximum of ten. At the two ends of the main ridge crouch the chīwěn (鸱吻 / 螭吻), dragon-like beasts that "swallow" the ridge to ward off fire and evil. These beasts are both ornament and talisman, and their number is a precise index of a building's ceremonial rank.

The Forbidden City's Golden Sea

The Forbidden City's roofs together use well over ten million glazed tiles, the Hall of Supreme Harmony alone carrying tens of thousands of yellow pieces. The Ming imperial kilns at Liuliqü employed around two thousand artisans and could fire millions of tiles a year to feed the capital's endless construction and repair. Walking the central axis, one passes from hall to hall beneath an unbroken golden canopy — a deliberate spectacle of unity and permanence that the glaze, more than any paint, was able to sustain against the northern weather.

Craft, Decline, and Revival

After the fall of the Qing in 1911 the imperial kilns closed and the craft of imperial yellow glaze nearly vanished; some recipes were lost for decades. Restoration of the Forbidden City and other monuments later revived the techniques, and the Liuliqü workshops continue to make traditional tiles for heritage projects. Today glazed tile is again produced by hand for temples and reconstructions, and the distinctive glint of a Chinese roof remains a living craft rather than a museum relic.

Glazed Tile Beyond Roofs

The same glaze that crowned palaces also decorated screen walls, gateways, and garden ornaments. The famous Nine Dragon Walls — at the Forbidden City, Beihai Park, and Datong — are built from thousands of individually molded, brightly glazed tiles. Glazed ceramic also clad pillars, thresholds, and niches, carrying the imperial palette into every corner of a sacred or royal precinct. The technology itself spread abroad to Korea, Japan, and Vietnam, where local variants of glazed roofing still echo the Chinese original.