Roofing in Denmark

Denmark is low-lying, maritime and without native building stone, so its roofs have been made of plant material, fired clay and, in the 20th century, fibre-cement sheet. Thatched roofs of water reed and straw were the ordinary covering of farmhouses for centuries and more than 50,000 thatched buildings still stand, while the island of Læsø developed a distinctive roof of dried eelgrass. Statistics Denmark records roof materials for every building in the country, making Denmark one of the few nations with a full register of its roofs.

Climate and hazards

Roofs face wind-driven rain, salt air and storms from the North Sea and Kattegat, with frequent freeze-thaw in winter. Fire has been the classic hazard for thatch, and asbestos in older fibre-cement roofs is a current concern.

Roofing history

Danish roofs were built mainly of plant materials for thousands of years. At Hedeby, the Viking-age trading town near today's Danish-German border, houses of the late 8th century had oak frames and probably thatched roofs. Thatch remained the normal rural roof through the medieval and early modern periods, on half-timbered farmhouses and vicarages such as Kølstrup near Kerteminde on Funen. Liselund on Møn, built in the 1790s, is unusual as a neoclassical house with a thatched roof.

On Læsø, salt boiling in the 17th century stripped the island of trees. Reed was hard to bring to the island and straw was needed as fodder, so islanders roofed their houses with eelgrass gathered from the shore. Surviving seaweed roofs date back to the 1650s.

From the 19th century, houses in towns such as Skagen were whitewashed or painted yellow and roofed with red clay tiles. After the Second World War, functionalist houses and public buildings often had flat roofs. Corrugated and flat fibre-cement sheets, many of them containing asbestos, became one of the most common roof coverings on houses, farm buildings and garages.

Traditional and vernacular roofs

• Stråtag (thatch): reed or straw laid in thick courses on steep roofs, typically finished at the ridge with turf, heather or wooden ridge pieces. See Dutch and Danish reed thatch.
• Seaweed roof: the eelgrass roofs of Læsø, laid directly on the roof beams by teams of 40-50 or more people and built up to 1.5 m (4.9 ft) thick. See Læsø seaweed roof.
• Tile roofs: red clay tiles on town houses, typical of places such as Skagen from the 19th century.

Roofing today

Statistics Denmark's register of buildings gave this breakdown of roofed area on 1 January 2026, out of 628.8 million m² (6.77 billion ft²) on 4.95 million buildings:

• Other roofing materials: 35.7%
• Fibre cement that may contain asbestos: 31.8% (200 million m², falling by 2.5% in a year)
• Tile: 13.4%
• Built-up flat roofs: 10.4%
• Asbestos-free fibre cement: 8.5%
• Green roofs: 0.2%

The same register counted 52,509 thatched buildings, a number that has fallen by an average of 335 a year over 15 years. Region of Southern Denmark has the most, with 33% of the total. Flat roofs are mostly covered with bituminous membranes.

Codes, standards and regulation

Construction is governed by the Danish Building Regulations, as of 2026 BR18 (Bygningsreglementet 2018), which cover structural safety, fire, moisture and energy performance.

Industry

The bituminous membrane brand Icopal originated in Denmark and is now part of BMI Group. See Icopal. The Nordic membrane group Nordic Waterproofing also operates Danish brands. See Nordic Waterproofing.

Notable roofs

• Læsø seaweed houses, part of a salt-production cultural landscape on Denmark's UNESCO Tentative List since 2023.
• Liselund, Møn, a thatched neoclassical country house of the 1790s.
• Skagen, known for its yellow houses with red-tiled roofs.

Local roofing terms

• stråtag - thatched roof
• tang - seaweed (eelgrass)
• tørvetag - turf roof

Sources and gaps

Statistics Denmark does not break down its "other materials" category, which covers more than a third of roofed area.