The ABC of Thatched Roofs

Base coat
First and lowest layer of thatched roofs.

Biddle
Construction similar to a chair or a ladder made of wood or aluminium and securely hooked through the thatch into the battens. Apart from the „Laufbaum” (a timber on which you can move on the roof) the biddle is the only basis for the work of the thatcher.

Bottom layer
A layer of reed of approx. 5 cm thickness that is applied to the lathing prior to the proper reed covering, in order to prevent the first reed layers to be pushed under the roof battens.

Brow course
The lower horizontal edge of the thatched roof consisting of two reed layers.

Bundle
Smallest unit of reed.
Measured at 30 to 40 cm from the butt end it has a diameter of between 45 and 80 cm.

Cold roof
Ventilated type of thatched roof construction.

Crooks
Hand carved or sawn rods with a handle that hold the sways to the reed.

Dormer
A dormer is an opening in a sloping roof. It serves to supply the attic floor with light and air.

Drip Board
Overlapping boards beneath dormers or the chimney and serving as an additional protection against rain.

Drip Divot
Grass sods being used instead of Drip Boards.

Eaves
The lower edge of the thatched roof from which the water of the main coat drips off.

Eaves Layer
Name for the difference in height between the bearing edge of the bottom side of the roof skin (eaves board) and the level of the tilting board. The eaves Layer of thatch is the foundation for the rest of the roof, it is bowed and held securely, by being fixed over a raised tilting board.

Feather
The spike of the reed stalk.

Hard roof
Consists of tiles, stones or of concrete roofing stones. This roof in contrast to the soft roof is not at risk of fire.

Heather ridge
The heather of the heather ridge is either secured on the ridge with wood nails (liggers), mesh wire or oaken ridge lumbers Instead of heather also straw, sea weed or hay can be used.

Hip
The edge running from the ridge to the eaves where two sloping sides of the roof meet.

Hot roof
A non-ventilated roof construction for thatched roofs, where the reed layer serves as heat insulation. In course of the discussion about the durability of thatched roofs the hot roof has met with criticism.

Inclination of the stalks
An important constructional prerequisite for the longevity of a thatched roof.
The inclination of the individual stalks in the roof should be at least 30° (as of 10.04.2007).

Lathing
Roof battens running horizontally and attached to rafters. They help to carry the roof skin.

„Laufbaum”
A timber on which you can move on the roof. Foothold for the thatcher which can be attached to the lathing of the roof after the fourth layer of reed with iron hooks or a rope. In the course of thatching the ”Laufbaum” moves up to the ridge.

Legget
Wooden board with a handle used by thatchers to hit the end of the stalks and to push them into position. This makes the roof more solid and beautiful.

Ligger
A thumb thick timber rod used to secure the ridge.

Moawer
With this handcrafted moawer reed can be harvested even on thick ice.In its construction it is similar to a wheel barrow without a wheel, with a ground edge that cuts the reed stalks.

The „Owl Hole”
The pediment at the ridge of a hipped roof originally served as a flue. If the pediment is left open owls can nest under the roof.

Pin
Flexible rod for the thatching of valleys, dormers and hips.

Reed
Reed is used for thatching and is harvested in or near lakes, river courses and in seaside areas either manually or with harvesters.

Reed caps
The converging verges or hips which are covered with reed lying almost horizontal. Inside of this triangle there is the owl hole.

Reed cutter
An auxiliary tool used to cut the reed bundles to different lengths.

Reed harvest
The reed can be harvested manually with a reed scythe, a sickle or a mower. The reed is cut in winter after the first frost, when the leaves of the reed have fallen off. Directly after the harvest the stalks are fluffed and thus cleaned. Then they are tied together to bundles.

Reed needles
Needle used to sew reed onto the roof construction. The following types of needles are used: Chain stitch needle lose needle, rounded needle, wire needle, shuttle needle, ridge needle, pull and stick needle.

Reed thatched ridge
Apart from binding material very fine reed is used for the reed ridge. The reed is fixed to the ridge battens with a twin seam. In contrast to the technique applied when thatching the main coat, the reed is attached with the flower (the spike) of the reed facing downwards. Then it is cut in layers.Generally there are three different ridge designs: Angeliter Fasslag, Mecklenburger Stoßlage or the English Reed Ridge.

Ridge
The ridge on the roof of a building is the part at the top where the two sloping sides meet. The ridge is also called ridge line or apex.

Ridge Layer
Last and next to last layer of reed at the ridge. The reed of the ridge layer is cut to a certain extent, so that it does not protrude over the ridge.

Ridge Lumbers
Two wood laths perpendicular to each other that sit like a rider on top of the reed ridge in order to protect and stabilise it.

Roof overhang
The part of the roof (eaves, verge) that projects over the exterior walls of the house.

Roof skin
The roofing material attached to the substructure is part of the roof that protects from wind and weather.

Roof slope
The roof pitch of soft roofs should not fall below 45°. The lower the roof pitch is, the higher is the danger that the roof might be damaged by storms. In rainy and stormy regions the roof should have an inclination angle of at least 50°.

Roof structure
This is the term for the structure of the roof. The supporting structure provides a basis for the roof skin, which, according to circumstances and requirements, may consist of rafters, purlins, stringers or other materials.

Sod-covered ridge
To cover this type of ridge grass sods are cut (preferably from salt meadows on the North Sea coast) and are placed along the apex so that they overlap. Afterwards they are secured in the thatch with liggers.

Soft roof
Consists of cereal hay, wood shingles or reed canes.

Stopper
Bundle, a hand-breadth thick and cut to a length of 45-50 cm. These bundles are used to stopper holes in a thatched roof.

Storing reed
In order to prevent a premature embrittlement of the reed harvested, the reed is put up in bundles to form a circle. At the same time, this helps the rain to drain off well from the outer layer. For the quality of the reed its storage plays an important role.

Sways
Wooden rods used to fix the reed before it can be sewn.

Tension angle
This is an important constructional prerequisite for the durability of thatched roofs. The angle means, that already the first layer of reed can be sewn under tension in order to prevent that later on the reed slips out of the tie. The tension angle is achieved by the constructional design of the exterior wall or of the lowermost roof batten.

Valley
Two roofing planes, running from the ridge to the eaves, meet at the bottom of their pitch to form a valley.

Verge
The edge of the roof projecting over the roof gable and running from the ridge to the eaves. Can come with or without a gable board.