A water reed roof has the eaves dressed into position with the use of a leggett and not cut with a knife as with Long straw and combed wheat reed.  The roof is often capped with sedge that is rare in wheat thatch.  Sedge when new is a mid-light brown whereas a new straw ridge is yellow; but once weathered it is difficult to distinguish between the two.  Many roofs, thatched in water reed, are known to have lasted at least 70 years.

Rethatching in water reed necessitates the removal of all existing thatch back to the roof timbers.  Where it is necessary to add new rafters these can usually be fixed at the side or above the old.

REED QUALITIES

Reed Length (a description)

Short reed should be between 3 ft (914 mm) and 4 ft (1220 mm).
Medium reed should be between 4 ft (1220 mm) and 5 ft 6inches (1676 mm).
Long reed should be above 5 ft 6" (1.7 m) with the majority of the reed around 6 ft. (1.8 m). Any reeds above 6 ft 6" (2 m) should be notified to the thatcher.

Reed Shape (the common terms)

Tapered Reed: There are degrees of taper and it is useful to discover this as:

Straight Reed: (meaning cylindrical ) reed with little taper is often sought for large expanses of unbroken roof areas. It is more desirable when associated with good length i.e., medium or long. It is also liked for slacker pitches.

Big Topped Reed: is often required for valleys and roofs in difficult drying conditions. It is most sought after when long and coarse - which are the associated qualities for helping difficult roof performance. This reed is often confused with bent topped reed which may or may not be "big topped " Some thatchers are quite happy to take bent topped reed as long as they are made aware of the other accompanying qualities. Slightly open reeds are preferred by many in difficult drying conditions, where the openness improves air circulation.

Twisted and Dog-Legged Reed: has very few favoured applications and is mostly not wanted.

Reed Stems

Sometimes specific butt types are required. The butts are described in terms of:
Reed Stem Diameter : This is important for achieving a good finish or when a coarse reed is required for durability purposes. 
Reeds of a diameter of 1/4" (6 mm) and over are regarded as coarse. 
Reeds of a diameter of 3/16" (4.8 mm) are considered as medium. 
Reeds of around 1/8" (3.2)mm) are considered fine. 
Any reeds in excess of 3/8" (9.5) in diameter should be notified to the thatcher

Reed Strength

Reed strength is a major factor in thatched roof performance. This should not be confused with hardness when the reed may also be brittle. The reed should have a fibrous quality and should not break easily.

Reed Colour

Reeds come in a variety of shades. It is not known whether colour, has on its own, an affect on performance. However reeds should have a good bright clean appearance. Good reed often has a glazed appearance at the butt. Dark dull reed is often brittle, (this should not be confused with reed with mud covered butts). Very pale reed is sometimes lightweight, this should be checked when it occurs, as it may be attributed with weak stems.

Note: A reed bunch is made up of hundreds of reed stems, all will vary greatly and show differing degrees of the qualities previously listed. Reeds can only be considered as a bunch by taking an average of the reed stem condition throughout the bunch.

TECNICAL SPECIFICATIONS FOR WATER REED