Roofing in Georgia

Georgia, in the South Caucasus between the Black Sea and the Caspian, has two roofing traditions that stand out internationally: the darbazi house with its stepped, corbelled timber roof, and the medieval church with a conical dome raised on a tall drum. In the high Caucasus, Svaneti's stone tower houses add a third distinctive form.

Climate and hazards

Georgia runs from the humid Black Sea lowlands in the west to drier, continental Kakheti in the east and the snowy Greater Caucasus in the north. Mountain villages such as those of Upper Svaneti sit on slopes beneath snow-covered peaks, so roofs there must carry snow. The region is earthquake-prone.

Roofing history

Classical antiquity. The Roman writer Vitruvius, in the 1st century BC, described a dwelling of Colchis (western Georgia) made of stacked timber, often cited as the ancient prototype of the darbazi.

Early churches. Most Georgian churches before the 9th century were basilicas. Tsromi church dates to the 7th century.

Cross-dome churches. From the 9th century Georgian builders developed the cross-dome church, with a conical dome raised high on a drum (tholobate) over a rectangular or cross-shaped plan. Pillars were introduced to carry the drum. In the 11th century windows were added to domes and walls to light the frescoes; drums typically had twelve windows, and from St Saba's Church onward sixteen (eight real, eight blind). Domes became heavier-looking in the 13th century and drums stumpier in the 14th, as at Gergeti Trinity, Zarzma and Chulevi. Svetitskhoveli and Samtavro (11th century) and Ikorta (12th century) are dated examples.

Vernacular continuity. The darbazi continued to be built into the 20th century.

Traditional and vernacular roofs

• Darbazi: a house whose main room is covered by a gvirgvini, a stepped pyramidal vault of hewn logs and beams that narrows to a central opening serving as both window and smoke outlet. It rests on pillars, with a central deda-bodzi ("mother pillar") bearing much of the load. Common in Kartli, Kakheti and Samtskhe-Javakheti. See darbazi.
• Svan tower houses: in Upper Svaneti, defensive towers of three to five floors taper toward the top as their walls thin, attached to two-storey houses whose ground floor sheltered people and animals. Chazhashi village alone preserves more than 200 medieval tower houses, churches and castles.
• Church roofs: conical domes on drums over cross-shaped roofs.

Notable roofs

• Upper Svaneti (UNESCO): tower houses of Ushguli-Chazhashi.
• Svetitskhoveli Cathedral, Mtskheta (11th century): cross-dome church.
• Gergeti Trinity Church (14th century): stumpy-drummed dome in a high mountain setting.
• Darbazi houses of Kartli and Kakheti.

Local roofing terms

• darbazi - house type with a corbelled timber lantern roof (from Persian darvāze, "gate")
• gvirgvini - the stepped corbelled log vault
• deda-bodzi - "mother pillar", the central timber post

Sources and gaps

Detailed climate data for roofing, data on current roofing materials in Georgian housing, information on modern roofing practice, codes and industry, and descriptions of the roof coverings of Svan towers and churches were not found in published sources.