Four Counties Thatching ltd
Water reed is used extensively in parts of the West Country and East Anglia. New properties are almost always thatched in water reed since it is the most durable of the thatching materials, and tends to give the longest life. Many factors influence the longevity of a thatched roof and it is therefore unwise to generalise on the subject. However a Norfolk Reed roof situated in one of the counties of East Anglia where there is a tradition of very steep pitches, could be expected to last an average of 50-60 years although there are instances of roofs lasting much longer than this.
When re-thatching with water reed, the existing material will be completely removed back to the roof timbers, although in the south-west of the country, where roof pitches tend to be less steeply pitched, thatchers often lay water reed on top of a base coat. The new reed is carried on to the roof in bunches and, starting at eaves level, is fixed directly into the rafters with the butts of the stalks exposed. Each layer of reed is held in place with either steel or hazel sways and once in position it is dressed into shape with the use of a legget.
Longstraw was once extensively used throughout the main corn crop regions from Dorset northwards, but is now confined mainly to the counties of East Anglia, although examples of it exist up and down the country. It is harvested with a binder. Old-fashioned long-stemmed varieties of wheat are grown and cut whilst still slightly green. After being allowed to dry, the wheat is threshed in a threshing drain and the resultant straw leaves the drum in a fairly mixed state.
Before longstraw can be used for thatching it needs to be made into yealms. A yealm can be described as a tight, compact layer of straw, which has been 'tidied' and is level at both ends. Yealming is a lengthy procedure which takes place on the ground and is basically carried out in order to straighten the straw and prepare it into manageable amounts for use on the roof. When re-thatching with longstraw, it is not usually necessary for all of the old material be removed from a roof. The thatcher will normally only remove existing material back to a base coat and the new straw is then fix to this with hazel spars.
Longstraw thatch is easily distinguishable from the other two types of material. It has long lengths of straw visible on the surface and has the general appearance of having been poured on, contrasting with the closely cropped look of combed wheat reed and water reed (see above). Longstraw also has exterior hazel rodding at eaves and gables - a feature seldom seen on the reed types. As it is more easily attacked by birds, netting is usually fitted to the whole of the roof.
COMBED WHEAT REED
Combed wheat reed, or 'Devon' reed is predominantly used in the south and west of the country. Although very similar in appearance to water reed, it is in fact straw. The grain is removed from the straw through a combing machine which is fitted to the top of an ordinary threshing drum. The straw does not then have to pass through the drum and comes from the machine with the butts all laid in one direction. It is then tied into bundles and stacked ready for use.
Combed wheat reed is applied to the roof in a similar fashion to water reed, dressed into shape with a legget. However, as with longstraw, it is not necessary to remove all the existing material from a roof prior to re-thatching.
Although there are national average figures quoted for the longevity of each type of material, these are of little use as judgements on performance - or likely performance - can only be made in individual circumstances. The performance of thatch depends on many factors such as roof shape and design, the pitch and its position (geographically and topographically), the quality of the material and the skill of the thatcher.
RIDGES The ridge of a thatched roof bears the brunt of the weather and, as the fixings are external, it requires attention on average every 10 to 15 years. The material used is usually the same as that used for the main coat-work, however, water reed is too stiff and brittle. As a result, the ridge of a water reed roof is often made with sedge.
The patterned ridges which have become popular allow the thatcher some artistic licence, but they are a relatively new innovation and as such are thought to be unsuitable for the majority of historic thatched properties. Different considerations apply in the re-thatching of an old building and one of recent date and it is probably fair to say that a house built prior to the 19th Century requires good plain workmanship without too much embellishment.
There are two main types of ridge - the 'wrap-over' which is used most widely, and the 'butt-up' which is found mainly in the south-west of the country where its use would appear to have developed from the stiffer nature of combed wheat reed. The 'butt-up' ridge has the butts of the material forced together from either side to form an apex whereas the 'wrap-over' is formed by folding a thick layer of material over the apex of the roof and fixing it on both sides.
With greater awareness of the vernacular materials and style of particular regions, conservationists have realised the importance of maintaining (and even returning to) the historically correct thatching style and material pertinent to the area. Local authorities actively discourage the use of a 'foreign' material and in any case, listed building consent is required for alterations to a listed building. Furthermore, the awarding of grants for repairs and re-thatching is often dependent upon compliance with the thatching policy of the local council and consideration of a change of material will usually only be granted for exceptionally strong technical reasons.
A common misconception with thatch is the idea that it absorbs large amounts of water. This is not the case at all. Water is transferred down the roof from stem to stem until it drops from the eave. The steep pitches associated with thatched roofs allow for water to be shed at a very fast rate. When designing for thatch, ample allowance should be made for the projection of the eaves and gables to project water clear of the building, and the ground should be well drained.
Wind damage should not usually be a problem. The experience of the 1987 winds in the south-east of the country showed thatch to be more secure than many other forms of roofing materials. A greater cause for concern is the risk of fire in a thatched properly, although the risk however is probably overstated. Evidence shows that thatch fires are usually caused by the same kinds of hazards affecting all housing and that genuine thatch fires are extremely rare. Figures from the Dorset Fire Brigade indicate that of 3,000 fires each year, only 8-10 of these involve thatched buildings and in the majority of these incidents, the fire will have started within the building itself. The reality is that all thatched building owners tend to be more careful about the dangers and employ a number of fire prevention measures. Nevertheless, many thatchers now recommend the installation of a fireboard which is fitted to the rafters and gives at least a half hour's fire resistance. Depending on the material and position of the building, this might then be counter battened to provide air movement between the material and fire retardant.
When alterations to an existing thatched roof are planned or when designing a new thatched roof it is imperative that consultation with a Master Thatchers is sought and in the case of a listed building, with the conservation officer at the local council. Thatchers have no hesitation in recommending thatch as an ideal roof covering, provided that certain conditions are met. It is only those who work with the different materials and understand the complexities of thatch who are able to advise properly on the way thatch will work.
The ancient craft of thatching has a wealth of terminology that almost forms a language.
Brush up your thatch-speak here.
Apron: Single sided section of ridge to protect thatch under chimney or window
Arris: Rail - see 'Tilt'
Baby: (Long Straw) - see 'Roller'
Back Filling: Laid above battens and under main thatch, used to adjust the tilt of reed or straw
Band / Bond: Twist of straw, reed withy or bramble used to tie a bundle of thatch to roof
Barge: See 'Gable'
Barge Board: Solid board used as an alternative to turned gable
Batting / Bolting: Bundle of tied, threshed straw
Biddle: Working platform hooked into thatch
Binder: See 'Rod' and 'Sway'
Binder: Reaper for cutting standing corn
Bolder Reed: Norfolk Reed bundle containing mostly bulrush
Bottle: Tied yelm of straw for setting eave of gable
Box Gutter: Leaded gutter formed behind chimney
Brotch / Broach: See 'Spar'
Brow: The course after the eaves course
Bunch: Bundle of water reed 2' circumference, 1' above butt, usually at the tie
Butt: Thicker end of a bundle of reed or straw
Butting: Arranging the ends of the reed by dropping bundles or nitches onto board
Cheek: Side of window
Chimney Block: See 'Apron'
Coat: Layer of entire thatch
Cock Up / Cockscomb: Topmost bundle of straw turned to shed water back onto the ridge
Continental Bundle: Imported bundle of water reed 1m around circumference or butt, usually tied twice
Compty: Substandard materials or thatch
Combed Wheat Reed: Straw which has had the corn leaf and weed removed - varieties include Aquilla, Marris Wiggen and Marris Huntsman
Course: Layer of reed or straw laid across the roof
Crook: See 'Iron'
Dolly: See 'Roller' and 'Bottle'
Dressing: Pushing reed into final position
Drift: See 'Legget'
Dutchman: Type of Legget originating from the Netherlands
Eave: First course of thatch
Fathom: Six bundles of water reed
Flue: See 'Gable'
Fargle: A goodly handful of steel sways
Feather: Seed head on water reed
Flag: Leaf on straw
Fleaking: A weave of water reed laid over the rafters instead of timber battens
Gable End: The overhang of thatch at a gable of the roof
Gadd: Cut length of hazel between 1" and 3" in diameter
Gaddule: Bundle of gadds
Hazel: Corylus Aveliana (L) - used for spars, sways and rods - said to be hardier than withy
Hook: See 'Iron'
Iron: Thatching nail used to fix sway to rafter, trapping thatch
Knuckle: Handful of straw, bent double
Ladder: types Pole. Push-up and Hanger
Legget: Tool that grips the ends of the reeds and pushes them into position
Ligger: See 'Rod'
Long Straw: Straw thrashed but not combed. Varieties of wheat : Little Josh, Red Standard, Square Headed Master
Netting: A ¾" galvanised wire or ¾" polythene used to protect thatch from bird damage
Needle: Used to stich on the thatch
Nitch: Bundle of combed reed of weight 28lb or 14lb
Northampton Roll: Rolled and rodded gable end
Peg: See 'Spar'
Pinacle: Topmost bundle of ridging material used to shed water back onto the ridge
Pricker: Length of gadd about a yard long, used to fix sways on rick thatches
Ridge: Covering of supple straw or sedge grass, laid along apex of roof to bind and protect the main thatch. Types include wrap-over, butt up, flush, straight cut and patterned. Patterns include dragons' teeth, diamond, scalloped, clubbed, herring-bone and crossed.
Reeding Pin: See 'Spragger'
Roller: Continuous parallel bundle of thatch used to build up ridge
Rod: Hazel or withy, used to hold down thatch on the surface. Types include split, unsplit, apex, kettle and muff.
Rutland Cap: Peaked end at gable
Rye: Type of soft straw used for thatching
Sedge: Marsh Grass (Cladius Mariscus) used for ridging
Server: Skilled labourer
Set: See 'Tilt'
Sheaf: Bundle of unthrashed straw - 8 sheaves make a stook, 16 make a stock
Slapping: First course of ridge
Skirt: See 'Slapping'
Spar: A split length of hazel or withy, pointed and twisted to form a staple
Spit: See 'Spar'
Spot Board: Board for 'butting up' of reed bundles
Spragger: Pointed length of steel used to temporarily hold materials
Springing: See ' Tilt'
Stalch: A strip of thatch worked from eave to ridge
Standing Crop: The thatching materials whilst growing
Stool: Clump of Hazel
Straw: All types of straw which may be used to thatch - wheat straw is considered most suitable
Sway: Steel or hazel rod used with irons to secure thatch
Thrashing: Method of removing grain from straw
Tilt: The angle formed by tightening the sway between the top and the butt of the reed
Tilting Fillet: A 'V' section of timber fixed to the rafter to set the tilt
Twisle: A crank for twisting straw for grass bonds
Verge: See 'Barge'
Wadd: See 'Bottle'
Wand: Length of unsplit willow or hazel, less than 1" diam
Water Reed: Phragmites Communis obtained traditionally from East Anglia now additionally from European countries
Wimble: See 'Twisle'
Withy: Willow used for rods and sways - it is said to be less prone to woodworm - varieties include Black bar, Dicky Medoes, Swallow tail and Whissender
Yelm: Drawn and wet straw ready for laying