Water Reed Thatch

Water reed thatch is made from the dried stems of reed grown in wetlands and reed beds. In England it is often called Norfolk reed after the reed beds of the Norfolk Broads, although much of the reed now used in Britain is imported, including from eastern Europe and South Africa.

Appearance

A water reed roof has a close, crisp, brush-like surface, because the butt ends of the reed face outward. The reed is not trimmed with a knife; instead it is beaten ("dressed") into place with a flat, ridged wooden tool called a leggett. Ridges are usually made of sedge, because water reed is too stiff to bend over the apex. When new, sedge ridges are mid-light brown; after weathering they are hard to tell from straw.

Fixing

Bundles of reed are laid in courses from the eaves upward and held down with horizontal rods called sways, made of hazel or steel, which are fixed to the rafters with hooks or ties. Unlike straw roofs, which can be recoated over old work, a water reed roof is normally stripped back to the roof timbers before rethatching.

Grading

Reed is sorted by length, shape and stem thickness. Thatchers' associations classify lengths as short (3-4 ft, 0.9-1.2 m), medium (4 ft-5 ft 6 in, 1.2-1.7 m) and long (over 5 ft 6 in, most around 6 ft or 1.8 m). Stem diameters range from fine (about 1/8 in, 3 mm) to coarse (1/4 in, 6 mm, or more). Good reed is bright and clean; dark, dull reed is often brittle.

Durability

Water reed is regarded as the most durable thatch. A steep East Anglian roof might average 50-60 years, and many roofs have lasted 70 years or more; imported reed on an average English roof is more likely to last around 40 years. The sedge ridge needs replacing more often, typically every 10-15 years.

Conservation issues

In areas with a straw-thatching tradition, replacing long straw or combed wheat reed with water reed can change a building's historic character. Historic England notes that numerous planning appeal decisions have found such changes harmful to listed buildings.