A Craft Shaped by the Land

Drive through the lanes of Norfolk, Devon or Herefordshire and the odds are good that sooner or later a long, low roofline will rise out of the hedgerow, pale and deeply shadowed, looking as though it has grown from the ground rather than been built upon it. Thatch is the oldest roofing material in Britain, made from what the surrounding fields happened to grow, and for centuries it sheltered everything from labourers' cottages and farm barns to village churches. Today roughly a few tens of thousands of thatched buildings survive, most of them listed, and almost all of them are kept sound by a small, stubbornly skilled workforce of thatchers.

What makes the craft worth defending is not simply nostalgia. A well-maintained thatch roof is a brilliant piece of low-energy engineering: the material is a renewable by-product of agriculture, it breathes, and it insulates far better than slate or tile. The catch is that it only works if it is laid and kept correctly, according to methods refined over generations.

Water Reed, Combed Wheat and Long Straw

The first lesson any thatcher will give you is that "thatch" is not one material but several, each with its own character and lifespan.

• Water reed, often called Norfolk reed, is grown in the fenlands and cut in winter. It is laid in tight, straight courses and lasts longest, commonly forty to sixty years, which makes it the material of choice for exposed coastal roofs and for buildings that are costly to scaffold.
• Combed wheat reed, confusingly a straw rather than a reed, is threshed and combed to remove the grain and leaves. It gives a softer, rounder surface and a life of perhaps twenty-five to forty years. It is the staple of Devon and Cornwall.
• Long straw is left uncombed and laid in generous bundles known as yealms, producing the lumpy, deeply textured roof most of us picture when we imagine a cottage. It is the cheapest option and the shortest lived, often fifteen to twenty-five years, but it is also the most historically authentic in many midland and eastern counties.

Choosing between them is a matter of climate, budget, building and local tradition. A conservation officer will usually expect a repair to match what was there before, and rightly so.

Spars, Sways and the Thatcher's Kit

The toolkit has barely changed in two hundred years. A legget is a wooden paddle used to dress and beat the straw into shape. A spar hook cuts and twists hazel. A rooping needle carries tarred cord through the roof, and a heavy mallet drives home the fixings.

The fixings are the quiet genius of the craft. Long hazel rods called sways run across the surface to hold each course down, stitched through to the rafters. Spars — short hazel or willow sticks, pointed at both ends and twisted in the middle — are bent over the sways and driven into the thatch to pin them. On a long straw roof, poles known as liggers are laid across the ridge and secured the same way. Nothing is nailed, glued or screwed; everything can be lifted, adjusted and reused.

A thatcher works from the eaves upwards, one course at a time, each overlapping the one below so water is shed outwards. A roof is built to a thickness of around 300mm, sometimes more, and to a pitch of forty-five to fifty degrees, steep enough to throw off rain before it can soak in.

Ridges, Scallops and Local Character

The ridge is the roof's weakest point and its most decorative. Because it takes the full force of weather from every direction, it is renewed roughly every ten to fifteen years while the main coat lasts decades.

Regional style shows most clearly here. In Norfolk and Suffolk you will see a block-cut ridge with scallops, semicircular shapes worked into the edge with a spar knife. In the West Country, ridges are often finished flush and decorated with diamonds, herringbone or simple bands. Different counties favour different patterns, and thatchers tend to learn one tradition thoroughly before adapting others. The result is a roof that tells you where you are.

Keeping a Roof Sound

Thatch is remarkably durable, but it rewards attention. A few practical habits will add years to any roof:

• Look it over each spring and autumn. Slipped spars, loose netting and bald patches are cheap to fix early and expensive to fix late.
• Keep gutters and valleys clear so water is not thrown back into the eaves.
• Sweep chimneys regularly and fit a spark arrestor. Most thatch fires begin at the flue.
• Never pressure-wash or seal a thatch. It must be allowed to breathe and dry.
• Watch for birds and rodents pulling at the straw, and for moss that holds moisture against the surface.
• Tell your insurer what you own. Specialist thatch cover exists and is usually cheaper than a nasty surprise.

Inside, a brown stain on an upstairs ceiling in heavy rain is a signal to call a thatcher, not a builder.

Passing the Skills On

Becoming competent takes three to four years of full-time work; becoming a master thatcher, capable of stripping a roof back to the rafters and rebuilding it in a recognised regional style, takes considerably longer. The craft has appeared repeatedly on lists of endangered heritage skills, and the reason is straightforward: the work is seasonal, physical and weather-dependent, and there are fewer people to teach it than there were a generation ago.

Apprenticeships, college courses and conservation schemes now run alongside the traditional route of learning in a yard from an experienced hand. If you own a thatched property, the most useful thing you can do is build a relationship with a good local thatcher before you need one, keep a record of the materials and dates of previous work, and resist the temptation to patch a roof with whatever is nearest to hand. A building thatched in the right stuff, by someone who knows why it was done that way, will outlast us all.