Roofing in Israel

The defining Israeli roof is flat, concrete and crowded with equipment, above all the solar water heater (dud shemesh, "sun boiler"), which the country made mandatory on most new homes in 1980. Israel is widely cited as the first country to pass a solar building law, and over 90% of homes now heat water with the sun.

Climate and hazards

Israel has a hot, sunny climate with dry summers and a short winter rainy season, ranging from the Mediterranean coast to the Negev desert. Strong sunshine makes solar water heating effective.

Roofing history

Pre-Pottery Neolithic. Ancient Jericho (Tell es-Sultan), in the West Bank, has deposits going back to about 10,500 BC (see roofing-in-palestine). Round, semi-subterranean houses of the period had stone foundations and mud-brick upper walls; how they were roofed are not well documented in published sources.

Modern Movement. Tel Aviv's White City, built from the early 1930s to the 1950s on a master plan by Patrick Geddes (1925-27), is a UNESCO-listed ensemble of about 1,000 historic buildings by European-trained architects of the Modern Movement, adapted to local climatic conditions. Flat roofs are part of this architecture; many buildings have since gained rooftop additions, which conservation rules now control.

Solar water heaters. During a fuel shortage in the early 1950s, engineer Levi Yissar founded NerYah (1953), the first commercial solar water-heater manufacturer. By 1967 about 5% of households used solar water heating. After the 1970s oil crisis, Harry Zvi Tabor developed the prototype of the heater now on most roofs, and in 1980 the Knesset required solar water heaters on new homes.

Traditional and vernacular roofs

Traditional Levantine flat earth roofs and stone vaults belong to the shared heritage of the region (see roofing-in-palestine, roofing-in-jordan and roofing-in-lebanon).

Roofing today

• Flat concrete roofs dominate housing and commercial buildings, carrying solar water heaters, water tanks and plant.
• Solar water heaters are on over 90% of homes; the Ministry of National Infrastructures estimates they save about 2 million barrels (320,000 m³) of oil a year. About 445,730 m² of glazed collectors were in place in 2013.
• Rooftop photovoltaics: cumulative PV capacity rose from 0.9 MW in 2004 to 4,750 MW in 2022, and from 2023 all new commercial buildings must install rooftop PV.

Codes, standards and regulation

• Solar water heater obligation (1980): applies to new buildings under 27 m (89 ft), roughly 8-9 floors, except industrial and trade buildings and hospitals. Extended in 2012 to taller residential buildings, which must supply the top seven floors. Minimum tanks are 60 L (16 US gal) for one-room flats, 120 L (32 US gal) for two or three rooms and 150 L (40 US gal) for larger flats. Without solar provision, a construction permit is not granted.
• Rooftop PV for new commercial buildings: required from 2023.

Industry

NerYah (founded 1953) was the first commercial solar water-heater maker. Between 2010 and 2014 about 88% of annual solar water-heater installations replaced existing systems.

Notable roofs

• White City of Tel Aviv (UNESCO): Modern Movement flat-roofed buildings.

Local roofing terms

• dud shemesh - solar water heater ("sun boiler")

Sources and gaps

Data on other roof hazards, such as seismic and rain loads, and information on traditional roof construction, seismic and roofing codes and roofing manufacturers: published information is limited.