What Is a Thatched Roof?

History

Evidence of thatched roofing exists on at least one Iron Age fort in Wales estimated to be 2,300 years old, according to the BBC. The technique likely dates back even further -- to the Bronze Age some 4,500 years ago. The earliest forms of thatch simply used branches and leaves wound together to create a loose covering. As the method developed, thatchers bound reeds and dry straw together in very tight bundles. While some modern thatch is neat and compressed, builders still use the basic technique on beach and mud huts in some of the world's poorest regions.

The main tools of the traditional thatcher's trade are the legget, the shearing hook and the spar. The legget has a flat but dimpled face used to push the ends of the thatch material up into the surrounding straw. A wooden spar driven into each bundle of thatch holds it in place on the roof, though metal pins usually keep the material secure during building. The thatcher must trim all of the ragged ends of the straw once every bundle is in place. For this, he uses the sharp shearing hook, which neatly crops the thatch into smooth, uniform lines.

Thatch varies around the world according to the type of material found by local builders. For example, tropical islands with many palm trees have palm and coconut-frond thatch roofs. Similarly, pandanus leaves and those of a member of the agave family make good thatch material. Thatchers in the United States tend to prefer types of clean straw and water reeds. Reeds last longer and are easier to collect and work than straw, according to McGhee and Co. Roof Thatchers of Staunton, Va.

As an organic material, thatch begins to rot as soon as it's installed. The decomposition process may take 30 years or more, but thatched roofs require regular maintenance to remain reliable. Though traditional thatch poses a great fire risk, modern techniques use flame-retardant coatings. Many experienced thatchers will create a distinctive thatched pattern at the top or edges of a newly thatched roof for a decorative flourish.