Dutch and Danish Reed Thatch

In the Netherlands, Denmark and the North Sea coast of Germany, thatch is made mainly from water reed (Phragmites australis) rather than cereal straw. Reed thatch has a long history on farmhouses and cottages in these countries and, unlike in many places, has also found a place on contemporary architecture.

History

Thatch was the normal roof of the North Sea lowlands for centuries. Settlements such as Hedeby, the Viking-age trading town in what is now northern Germany near the Danish border, very likely had thatched roofs. Fire was a persistent danger in towns, and in the 16th century Holland required fireproof roof materials, which encouraged the use of clay tiles and helped create a large hand-made tile industry. Thatch therefore became mainly a rural roof.

In Denmark, thatch survives on half-timbered farmhouses and vicarages such as Kølstrup near Kerteminde, on manor houses such as Liselund on Møn from the 1790s, and on cottages in coastal dune landscapes. Danish growers have also experimented with silvergrass (Miscanthus) as an alternative thatching crop.

Technique

Reed bundles are laid in courses from the eaves upward and fixed to battens with steel wire, screws or stitching, then dressed with a wooden beater (a "leggett") to form a smooth surface. Thatch needs a steep roof, typically 45-55 degrees. Dutch and Danish ridges are often finished with a cap of clay ridge tiles, turf, heather or, in modern work, a metal or composite ridge.

Modern use

The Netherlands has a strong thatching industry, and reed roofs appear on new villas and public buildings as well as on restorations. The House of the Five Senses at the Efteling theme park in Kaatsheuvel, Netherlands, is often described as having the largest thatched roof in the world.

Supply and fire

Much reed used in north-western Europe is now imported, from Eastern Europe, Turkey, China and South Africa among other sources. Fire risk and insurance costs are managed through fire-retardant treatments, fire barriers beneath the thatch, and careful detailing around chimneys.