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How Long Does A Thatched Roof Last And How Much Do They Cost?

As archaeologists will know, thatching dates back at least as long as the bronze age. That makes thatching a skill that has been refined and passed down the generations for 10,000 years in Africa, Europe, Asia and beyond. It’s a building technique that has been replaced only relatively recently by slates and tiles, and it’s estimated that there are still more than 20,000 thatched homes and businesses in the UK.

How long does a thatched roof last?

The lifespan of a thatched roof depends largely on how well it was built, how steep it is, how often it is maintained and which material is used to construct it. The prevailing weather is also a factor (the drier the better), and thatched roofs under trees can deteriorate more quickly as the sugars dripping off them can help bacteria to breed.

Generally speaking, though, the lifespan of water reed thatch is about 30 years, combed wheat is about 30 years, and straw is about 20 years. It’s not unknown for thatched roofs with regular maintenance to last up to 60 years, though! 

How much does a thatch cost to install?

Just like any construction project, thatched roofs have two costs: materials and labour. Both are influenced by the size and complexity of the project. So a small cottage with a simple pitched roof will cost considerably less than a large detached house with multiple chimney breasts, dormer windows and irregular features. Also, replacing an existing thatched roof will cost less than having a brand new one installed in place of a tiled or slated roof.

If you’re looking for ball-park figures, thatchers usually charge by the square, which is 10 ft × 10 ft (100 ft²), or 3 m × 3 m (9 m²). Prices vary, but an average price would be about £700 per square. 

A small cottage (say, 25 ft × 25 ft) with a 45° roof would have a roof area of 900 ft². That would cost about £6,500 to install.

A large detached house with several dormer windows and two chimney breasts would probably be in the region of £25,000 to £35,000.

It goes without saying that these are rough estimates, and that a thatcher would be able to give you an accurate quote based on their measurements and experience of similar jobs.

Are there maintenance costs?

Just like your car or boiler, regular maintenance is the key to getting good value for money and longevity out of your thatched roof. An annual visit from a thatcher is always a good idea; they should be able to inspect your roof and make any small repairs that need doing. This will probably come to less than £1000 a year. You might also have slightly higher home insurance premiums because of the fire risk.

What is thatch made of?

In the UK, there are three main materials used in the construction of a thatched roof: water reed, combed wheat reed and long straw. They each have their qualities and availabilities, and there’s some regional variation to the types. Long straw is less prevalent nowadays because farmers tend to grow shorter varieties of wheat as it’s quicker to grow and easier to harvest. Roof thatching used to be a by-product of agriculture, but now it’s grown specifically. Most of the reed used in British thatched roofing today is imported, usually from Hungary.

The original thatched roof is attached directly to the roof timbers. Bundles of reeds are fixed to the timbers angled downwards at about 20°, then piled on top of each other so that the final angle of the roof edge is between 45° and 50°. The steeper the outer angle, the better the roof will be at letting water run off, and that will prolong the life of the thatch. However, the steeper the angle, the taller it will need to be, and that means more thatch to pay for – so the angle is a compromise between water run-off and cost.

If a thatched roof is well made, water will only penetrate to about 50 mm, which is about 20% of the whole depth. Since the dry thatch will have a longer life, it’s possible to strip off the top layer every ten years or so but leave the lower layers in place. This can save a lot of work in the long run.

What are its advantages?

Thatched roofs have several advantages over slates and tiles:

  • The roof is naturally breathable, which prevents rotting
  • Because there is a lot of trapped air in the bundles and in the hollow reeds, they have great insulating properties, so there’s usually no need to insulate the loft
  • Thatched roofs are also cool in the summer thanks to low heat conductivity
  • They are made from natural materials, so there’s no mining or quarrying required, making them more environmentally friendly
  • They are beautiful and striking, adding character to any property
  • Because no guttering and drainpipes are required, there is a cost-saving
  • They can increase the value of a home
  • Thatch is lighter than tiles, so the roof timbers can be smaller

Does it have any drawbacks?

Thatched roofs are not without their disadvantages, although some of them are preventable.

  • They can be a fire hazard, although with fire prevention measures, they are very safe.
  • Because of the perceived fire risk, insurance premiums can be higher.
  • Birds can pull out the straws when looking for insects – this will require attention after a while.
  • If the angle is too gentle, rain and snow will not fall off efficiently, which can speed up rotting and, in the case of snow, overload the structure.
  • Thatched roofs need to be tidied up every few years, with new reeds replacing the damaged, rotted or lost ones.

Properties with thatched roofing are incredibly beautiful and quite unusual by today’s standards. This combined with their eco-friendly properties makes them highly appealing to those who love buildings with more character and personality. When all’s said and done, if you’re happy to treat it with respect and care, there’s no reason you can’t enjoy your thatched roof for decades to come.

Find out about other types of roofing.

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