Written by Nicky Hughes
Archaeological evidence suggests that thatch in Britain may date back more than 9,000 years to the Middle Stone Age.
This traditional natural roofing material has continued to be used across the millennia, particularly in rural areas but also in towns and cities, until the latter banned thatch because of the increased risk of fire.
Before the industrial revolution brought better transportation and mass-produced roofing materials, thatch was used in areas where the raw material was available. In other areas, other local solutions were found such as stone slates.
The Industrial Revolution (mid-18th to mid-19th centuries) was seismic in its influence – shifting the country from an agricultural and crafts-based economy to a manufacturing one.
Thatch, although still prevalent in the countryside, particularly in the south-west, went into general decline from an estimated 1 million properties at the start of the 19th century to around 35,000 in the 1960s. Thousands of buildings across the country had been roofed instead with tiles or slates that could be conveniently produced and transported.
Today, Historic England estimates there are around 25,000 listed historic thatched properties, mostly in the south-west.
New thatched buildings have seen a quiet uptick as modern architects rediscover thatch as being both aesthetically pleasing, as well as sustainable and eco-friendly.
Aerial photographic evidence recently published by the Ordnance Survey estimates the overall number of thatched roofs at 33,448.
Prehistoric thatching
It is believed thatching materials may have been used in England around 9,600 years ago.
At the beginning of the 21st century, on the edge of a sandy cliff near the village of Howick, Northumbria, archaeologists discovered a circle of substantial post holes, including smaller ones angled inwards. The sturdy construction suggests that the roof covering was heavy, possibly a combination of turf and reed thatch.
Scientific dating suggested the house was originally constructed about 7,600 BC during the Mesolithic period. It may have been lived in for several generations.
Based on the evidence, between 2000 and 2002, a team of archaeologists reconstructed the house (shown below suffering from the effects of harsh weather). It was dismantled in 2010 after becoming structurally unsound.
Archaeologists have found actual remains of clumps of thatch that are around 3,000 years old from the well-preserved Must Farm site, Cambridgeshire. Here roundhouses were built on stilts above a small river. The conical roofs were built of long wooden rafters covered in turf, clay and thatch. The settlement was destroyed in a fire.
Types of thatch
Historically, thatching was predominately used for cottages and agricultural buildings, using lightweight plant stems readily to hand locally for roofing wattle and daub and cruck beam buildings.
Over the centuries, many types of natural materials have been used as thatch, including heather (more common in northern England and Scotland), sedge, broom, flax, bulrushes, bracken, turf, various grasses, water reed, long straw and combed wheat reed. Today, only the latter 3 materials are widely used.
Water reed historically grew in Norfolk reed beds specifically created for thatching purposes. Today, about 97% of reed is grown abroad, mainly in eastern Europe. In England it is now primarily harvested in East Anglia, but with small pockets of productive reedbeds elsewhere; a particularly long-established one being on the Abbotsbury Estate in Dorset, where it is still harvested to thatch estate properties.
The reeds grow to nearly 2.5 metres tall and are cut near the base of the stem. Being hollow, they are lightweight and relatively stiff, meaning they need to be laid on an even base, with all the old thatch removed first. Water reed roofs tend to be thinner and more uniform in appearance.
Combed wheat reed is known as ‘reed’ because it looks similar to water reed and is quill-like and closely packed on the roof.
However, this thatch derives from wheat straw. It is passed through a reed comber first, which removes the grain without crushing the stems, then bound together with the stems all lying in the same direction.
Combed wheat reed traditionally produces a neater but more curved profile than either longstraw or water reed. This is partly because (like longstraw) it is generally applied over existing sound coats of straw which over time can build up a considerable depth, but also because its eaves are firmly dressed to a more sculptured rounded shape. The eaves of longstraw roofs are traditionally fixed with an external lattice of hazel rods (known as ‘liggers’).
The other distinction between a combed wheat reed roof and a longstraw roof is that it is the densely packed, butt ends of the straw that are visible on a combed wheat reed roof whereas on longstraw the fuller length of the stems are visible, laid in a more loose form, with both butt and eared ends exposed, creating a distinctive shaggy appearance. These distinctions are, however, becoming more blurred now as some thatchers have developed a ‘hybrid’ form of thatching, for example mimicking aspects of the appearance of a longstraw roof with combed wheat reed.
Long straw, straw from wheat growing, was once the commonest form of thatching in most parts of England, especially in the south and east. Its particular look derives from its preparation on the ground.
The threshed straw is shaken into a layered bed with no regard to uniformity. Stems remain unaligned. They are wetted and allowed to steep, becoming more flexible, then gathered together into compacted bundles.
Long straw thatch can be patched over previous work (as can combed wheat reed) if the roof starts to decay, rather than wholly replacing the roof cover as with water reed. The accumulation of multi-layers of thatch over the decades creates a softer, more rounded, picturesque appearance. In thatching terminology extensive repair to a whole roof is called applying ‘new coatwork’, since they are effectively re-coating the roof in thatch.
Thatch as archaeological evidence
A few hundred buildings survive in England with soot-blackened thatch on the underside of the roof, indicating medieval origins when there was no first floor and the smoke from an open fire went straight up to the rafters. Where smoke blackened thatch survives, this means that the lower layer of thatch has not been removed since the medieval period, which makes surviving examples very important.
These buildings offer important archaeological evidence of the thatching materials and techniques of the period, as well as insights into the history of the the local agriculture and botany. Most of the surviving examples of smoke blackened thatch come from Devon along with some from other western counties.
How a thatched roof is constructed
Thatch is the quintessential vernacular English country roof covering, with the different traditional materials and roof construction – including eaves, dormers and ridges, alongside knowledge and skills passed down through the generations from thatcher to thatcher – resulting in regionally distinctive styles.
But the principles of thatching, simple in concept but a supremely skilled craft, are broadly similar. For a typical new thatched roof today, an underlayer of thatch is first laid on the roof, fixed to battens spanning the rafters. Thatchers often price according to a ‘thatcher’s square’ which is a measurement of 3 metres by 3metres.
The main coat is applied on top of this. Tied bunches of thatching material are laid side by side across the roof in horizontal courses to cover the entire roof surface, secured in place with fixings, with each bundle overlapping the previous one. This process continues up to the ridge.
Ridges are usually made of straw, used for its pliability. They are either flush – the traditional type of ridge on the vast majority of historic thatched buildings in England – or taking the form of a diamond-shaped or scalloped raised block on the roof line; the ornate surface pattern created by hazel or willow spars. The apex is sometimes decorated with finials of animals or birds.
Many thatched roof buildings have low eaves and their first floor rooms are lit by windows either wholly or partly in the roof. These may be either ‘eyebrows’ where the alignment of the thatch doesn’t change but the eaves of the thatch curve gently over the window, or full dormers where the angle of the thatch changes to accommodate a larger or higher window.
Thatched roofs can be vulnerable to damage by birds and rodents and netting can help to protect them from that risk.
East Anglian properties tends to have steep roofs with angular thatches (above), whereas in the West Country roof pitches are less steep and thatch shapes more rounded (below). Historically, the differing styles of thatch in East Anglia and the West Country related partly to the use of different materials: water reed lending itself to more sharp angles and its single coat application making it easier to maintain a steeper pitch than the multi-coated straw roofs of the south-west.
A sustainable roofing material
Thatch is sustainable and eco-friendly. It offers natural sound-proofing and insulation, keeping buildings cool in the summer and warm in the winter, while its highly effective weather-proofing means there is no need for gutters or down pipes.
Thatch can have a low carbon footprint, particularly if it can be sourced locally, though Historic England acknowledges this can be difficult. By contrast, if you thatch a property in water reed, the material will probably have travelled a long distance to reach your property. There are only limited use of fertilisers in its cultivation and when it has served its purpose, the used material can be composted rather than ending up in landfill. Historic England encourage all thatched property owners to be curious about the provenance of the material they are putting on their roof and concerned about the sustainability of its production.
Thatched roofs can potentially last up to 50 years but may have a shorter life-span. Their ‘life-expectancy’ can depend on factors such as the location of the building, the technique and the quality or condition of the materials used.
5 unusual thatched buildings
Causeway House in Northumberland
This is a rare survivor of a heather-thatched building. Such thatch was known locally as ‘black thatch’; its use dwindling once slate became a cheap and durable alternative.
The farm building was abandoned decades ago but, during restoration, inspection of the thatch revealed two late 19th century dresses, a child’s shoe and an iron spoon stuffed into holes. These may have been hidden there as good luck charms.
Mummified cats have also been found thatched into roofs for similar reasons.
St Peter’s Church, Markby, Lincolnshire
This is Lincolnshire’s only thatched church, one of around a dozen to survive in England. Although most parish churches would have been thatched in the Middle Ages, St Peter’s was originally tiled, having been built using fragments from the ruins of the local priory. It was not thatched until 1672 when the local church warden offered to thatch it in return for being given the roof tiles.
Thatched model village housing, Milton Abbas, Dorset
In the 18th century, wealthy landowners built model villages to improve the aesthetics of their land, getting rid of what they perceived as the ‘eyesores’ of ancient estate villages.
One of the best known examples of this was created by the Earl of Dorchester, Joseph Damer (1718 to 1798), who had remodelled Milton Abbey into a great house, with landscaping by Capability Brown (1715 to 1783).
The Earl ordered the demolition of the remnants of the original medieval village adjacent to the mansion, before housing the estate’s agricultural workers in the newly-built vernacular-style model village of Milton Abbas.
Stembridge Mill, High Ham, Somerset
This is the last surviving windmill with a thatched cap in England, its commercial use ending in 1908. Such windmills were once a common sight across the country.
The milling machinery originally drove 2 pairs of grinding stones. In 1897 it was converted from wind power to steam, and the driveshaft and gears still remain.
Acquired by National Trust in 1969 when it was bequeathed by its then owner, it has been restored in stages over the years, with new sails added in 1971.
The Bear’s Hut, Killerton House, Devon
This is an eccentric example of a rustic-style summer house. It’s set within the landscape of the late 18th century Killerton House – built by Sir Thomas Dyke Acland, the 7th Baronet, for his wife Lydia.
The interior, with its stained glass windows, is roofed in deer skins and floored with deers’ knucklebones; the exterior topped with a thick rounded thatch made of combed wheat reed.
The building’s name derives from the time in the 1860s when the Acland family used it to house Tom, a pet Canadian black bear.
Thatch in the contemporary era
After decades of campaigning, the American actor Sam Wanamaker realised his vision of a reconstruction of the nearby lost Elizabethan playhouse that originally showed William Shakespeare’s works nearly 400 years ago. The new Globe Theatre opened in 1997.
The theatre was constructed as authentically as possible, including creating a water reed thatched roof – the only one permitted in London since the Great Fire of London, 1666.
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Today, architects are rediscovering and reinterpreting thatch for the modern age.
Here vertical thatch is used as cladding on the Enterprise Centre, a pioneering highly energy efficient building employing natural and bio-renewable local materials.
Historic England’s role
Wherever possible, Historic England supports the continued use of authentic thatching materials and traditional techniques on listed buildings, as these are vital to preserving their historic significance. We understand that periodic shortages of thatching straw can make sourcing traditional material extremely challenging. Where detailed evidence shows that the usual thatching straw is genuinely unavailable, and where other reasonable options for protecting the roof have been explored, appropriate alternative thatch materials may be temporarily acceptable to ensure the historic buildings most in need can be repaired and protected.
Our role includes publishing advice for conserving thatched roofs, including around fire prevention and sourcing thatch for repairs. Working with others in the Traditional Thatch Project, we support thatching as a construction skill. Through research and guidance, Historic England is actively trying to encourage and support the sustainable UK production of thatch, be it straw or reed, so that indigenous and authentic material can continue to be used on the roofs of historic thatched buildings.
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