Thatch was the most common form of roof covering everywhere in Britain until the end of the medieval period and it remained the practical solution for many roofs in rural areas until the mid 19th Century.
Materials for thatching were those types of vegetation found readily at hand; wheat straw was the most widely used until the introduction of the combine harvester and the new varieties of shorter stemmed wheat in the 1950s. Long straw, combed wheat reed (Devon reed) and water reed (Norfolk reed), together with sedge as a ridging material, are the forms of thatch in most general use today. Heather remains in some areas; flax and rye are sometimes seen sandwiched as middle coats in old roofs. The wood chips of Sussex, which resemble coarse water reed in appearance, are now very rare.
The term “traditional” is difficult to apply to thatching because, unlike other building components, where really old thatch survives it is concealed by subsequent coats of thatch and it is not clear when innovations came about. Guidance form early photographs and paintings may help to ensure that old profiles and styles are maintained. Thatch is most effective, both in style and longevity, when kept simple; the ornate designs so often seen today are thought to have been rare before the 19th Century. Different considerations apply in rethatching an old building and one of recent date. A house built prior to the 19th Century requires good plain workmanship without embellishment.
There are distinct regional characteristics in the methods of thatching and within a region a thatcher may have his own style. The treatment of ridges, eaves and gables varies in different parts of the country and in those areas where there is a strong thatching tradition a departure in style may look out of place. If it is proposed that long straw be replaced by water reed, this may require stripping back to the roof structure which may destroy early and interesting fabric: it will completely alter the appearance of the roof and consequently the character of the building. Some planning authorities require Listed Building Consent to change from long straw to water reed; also where there is a grant aid policy for rethatching the local authority may resist a change of material. The changeover to water reed in wheat reed or long straw regions means the extinction of a whole tradition.
If you are about to rethatch or repair a thatched roof, contact your Local Authority’s conservation officer, who is usually based in the planning department. He/she will be able to advise on the need for consents, local policies and requirements concerning thatching materials or details to be used. Delays can be caused and work disrupted if you are not careful to obtain appropriate consents. Work can be stopped and reinstatement of materials or details insisted upon. Dialogue at an early stage between owner, architect, builder, thatcher and conservation officer can avoid this and any other difficulties that may occur. The Local Authority’s conservation officer will also give advice concerning the availability of grants. These are discretionary and conditions of offer vary from authority to authority.
VAT is in most circumstances payable on thatching work. Change of thatch type, even when completely removing the existing thatch and timbers, does not qualify the work for zero rating. Substantial alteration and rebuilding is required before the work is zero-rated. Never assume zero rating. In instances of new work and rebuilding for thatch, where the work is to be zero-rated, confirm the situation in writing with the local VAT office.