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Thatching Glossary

Common Terminology
( NB the following are a general guide to thatching terminology. You may come across local and individual terms that describe these same definitions).

The layer of thatch directly beneath a window or chimney. Often covered by an extra layer of thatch as a pad to protect the roof.

The edge of the thatch roof that overhangs the gable

Base/Lower Coat
The original layer of thatch that is often left in place when a roof is re-thatched. In particularly old properties there may be ‘smoke blackened’ thatch layers on the underside of the roof. This is protected due to its historic importance and must not be removed.

Block Cut Ridge
This type of ridge stands proud of the main coat of the thatch. This type allows thatchers to decorate the ridge line in a personalised style. In many examples it is possible to identify the individual thatcher by the ridge patterning.

These are the individual bundles that form the eaves of the thatch.

Brow Course
The first course up from the eaves formed by the bundles.

The uppermost surface of the thatch. In the case of overcoating a new layer is fixed to the existing undercoats and may not be in the original material.

These are the steel nails used to fix the reed thatch to the roof structure.

Cross spars
These are lengths of split timbers used to decorate the ridge, eaves and gables of the finished thatch surface.

This describes the technique of aligning jumbled material for use as thatch.

Half rounded shape, similar to Leggett, used to help form valleys.

Although not a specific thatching term, flashing is the lead or cement strip applied around chimneys and other protrusions of the roof for safety.

This term describes the matting used on the underside of thatch above open rafters. These mats are often woven water reed and used in lieu of battens.

Flush Ridge
A more traditional type of thatch and one that many planning offices are keen to return to. The ridge is finished flush with the coat layer of the main roof. There are two common ways of achieving this finish, butt-up ridges is where the two sides are merged at the roof. The other method is when a single layer is wrapped over to form the roofline.


This describes the bats used to position the thatch on the roof. Typically one end is treated so as to catch the ends of the reed used. This tool is used by the thatcher to dress the reed into place and ensure an even finish.

Usually made from willow or hazel these are lengths of split wood that are used to hold the upper surface of the thatch in place. Once in position these fixtures perform the same job as sway rods but in a different position. In modern thatching these are used on long straw roofs to hold the eaves and verges. When a roof is re-thatched using water reed or combed wheat reed the use of these wooden strips is normally only used on the ridges.

This is tool used by thatchers to fix the thatch material to the battens. The needle is a flat sided implement that is used like a sewing needle to thread twine through to the battens.

These terms describe a raised end of a ridge overhanging a gable or roof hip. In many parts are decorated and help define the local characteristics.

Ridge Roll
When the ridge level needs to be higher a ridge roll is used. This is a tight bundle used to build up the height prior to the finishing layer.

This is the section at a junction between the main roof coat and a lower ridge.

This describes the layer of thatch out of which a pattern is cut into. This may be either surrounding the chimney or run along a block ridge.

Used to secure new thatch to older coats and liggers to the coat surface. Commonly used materials include willow and hazel. Twisted into a U-shape, they work by holding down a ligger or a sway to the upper surface.

This is a layer of thatch laid as work progresses. Typically ¾ m wide strips of thatch running from the eaves up to the ridge.

Traditionally wooden but now more likely to be made from steel used to secure the thatch to the roof. Each layer is placed horizontally above each preceding layer to conceal rods.

Tarred Twine/Cord
Often used to fix sways to rafters these are strong fibres strengthened with tar to hold together thatch to rafters or battens.

This is a layer formed by drawing straw from a bed of dampened or threshed material. It is for use in coat work or for the ridge.
In addition, yealming describes the process of preparing the material while on the ground before forming these yealms by the process of drawing.

Combed Wheat Reed (Devon reed, wheat reed, combed wheat)

1) A form of thatching straw composed of stems that have been combed mechanically to remove grain and extraneous waste material without crushing the stem.
2) The technique of thatching a roof with this material, using the material in bunches which retain a common orientation to the stems. The material is dressed into place and usually secured without external fixings other than at the ridge.

Long Straw

1) The technique of thatching a roof with straw, using yealms made up by drawing from a bed of threshed straw, the ears and butts lying both ways. The resulting material is laid on the roof and is tied down using spars and liggers rather than dressed into place as in water reed or combed wheat reed thatching,
2) The material used in this way, straw normally cut low on the stem by a reaper rather than a combine harvester.

Water reed (Norfolk reed)

1) Wetland plant (phragmites australis) used for thatching.
2) The technique of thatching with this material, which is carried onto the roof in bundles and secured, butts down with sways and crooks.


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