Thatch is probably the most common roofing material in the world, considering the readily available nature of the materials. Different materials are used across the world depending on local flora.

The UK and Republic of Ireland have more thatched properties than any other European country. Traditionally most Somerset thatch is wheat reed, which now is produced for the industry at specialist farms. Water reed is another common material. Using a good quality wheat reed, a skilled and experienced thatcher can create a thatched roof which will remain serviceable and watertight for over half a century. Water reed can, in the right conditions, last for over 70 years. Traditionally, if the existing thatch was in fair condition the new layers were simply added on top. In some ancient properties this has resulted in thatch 7 feet thick where the lower levels date back six hundred years.

Thatch is applied in fastened bundles about two feet across, laid on to the roof and secured to the beams of the roof. after which they are pegged in place with wooden rods. The thatcher adds the layers on top of each other, finishing with a layer to secure the ridgeline of the roof. Thatched roofs, because of this technique are very straightforward to repair and can withstand even heavy storms.

Well laid thatch does not need maintenance very often, occasional repairs will be required if it becomes damaged, especially after particularly bad storms. The ridge is the one part of the thatch which will need maintenance, as it is exposed, it is likely to need replacement every decade or two. Thatch 'thins' our over time as the reed is slowly eroded by the weather, this is natural and does not mean that the thatch needs replacement until the fixings are close to being exposed. Any water penetration that occurs in thatch, if it does happen at all, will be minimal. Leaks are usually caused by either storm damage or capillary action through the thatch. Moss growing on thatch does not necessarily mean that there is a problem. If you are worried about it, then it may be best to get an expert opinion.