Thursday, November 8, 2007
Thatch Roofs
Thatch roofs are still fairly common in England---there are more thatch roofs in the UK than in any other part of Europe. Thatch roofs are more frequently seen in some communities than in others. In Martock there are only a few (the photo above was taken in Martock), but it is just a short drive to a village where there are many thatch roofs. Even new construction has thatch.
Thatch is the most common roofing material in the world because of the availability of materials. It can be made of many different kinds of plant material. In England it is traditionally made with wheat straw. That straw is now produced by specialized growers, because the most common wheat of today has shorter straw than the older varieties. (The use of imported water reed is common in Eastern England.)
The wheat straw is fastened together in bundles with a diameter of about 2 feet. Then it is laid on the roof, secured to the roof beams, and pegged in place with wooden rods. Layers are built on top of layers, and then a finishing layer is put on to secure the ridge line.
This is the underside of a thatch roof. It is on a gazebo, so there is no ceiling below the roof.
If a roof is built by experts, it will last 45-50 years. The ridge line may have to be replaced sooner, but even that lasts 15 years. Thatch roofs are repaired by just adding a new layer. ( Sometimes in the really ancient buildings, the lower levels of thatch are 600 years old!) The labor intensive work of making a good thatch roof and the need for skilled experts make it an expensive roof today.
Thatch roofs do endure wind and rain, but I am not sure that they would make it through Texas thunderstorms! (One day several months ago, it was raining and I could hear two or three rumbles of thunder in the far off distance (no lightning). The next day people in Martock were talking about the bad thunderstorm!)
There is enough pitch to the roofs that rain runs off before it penetrates the lower levels of the roof. Especially in England they do not catch fire any more frequently than other roofs, because they are generally wet! However, if they do catch fire, mostly from chimneys, the fire does much more damage and is hard to put out. That makes insurance high. Many people put a fire retarding layer underneath the thatch. (In London, new thatch roofs have been against the law since the Norman days of the 12th century--and that was before the Great Fire of London. The old ones had to have a layer of plaster in the rafters. The Globe Theater has a thatch roof, but it is built over a regular-type roof!)
Another problem with the thatch roofs is birds. Wire netting is used to prevent damage from them.
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2 comments:
That's very interesting. I was wondering how they stand up to HIGH winds (you know...the kind that are on the leading edge of a bad thunderstorm)? Does it get really windy there?
Wind would be the first question of someone from Kansas!
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