There are three main types of thatch:
Perhaps one of the oldest forms of thatching. The art of long straw is dying out even among modern thatchers. Traditionally this method of thatching was one of the cheapest, but to be done properly it now commands a higher premium than other methods due to the vast amount of skilled labour it requires.
The straw I use is grown especially for thatching near Framlingham in Suffolk, and is still cut with a binder and left standing in stooks in the field before being stored ready for threshing. The straw is then shaken up into a heap, or bed, and soaked down. Once soaked in the straw is pulled out of this bed and fashioned into Yealms. These yealms are what I use to thatch with.
Many long straw thatched homes can develop a build-up of layers of thatch over the course of the buildings life. It may be the case that one or more of the existing layers may be entirely stripped off before the new thatch goes on. The new thatch is attached to the roof using twisted, split hazel pegs, or spars. The spars I use come from a hazel coppice a short walk away from my home. The management and development of such woodlands was once a staple part of the thatchers craft, but is now also beginning to be lost after equally good, but cheaper imports from Europe. Tens of thousands of these spars can be used on a single re-thatch.
Some thatcher’s have started to use a plastic version of the hazel spar. This is not a method I endorse or use. These plastic spits will save the thatcher a lot of time and money, but in the long run will prove detrimental to your thatch. Also, they’re plastic, and have no place in my craft.
The thatch is normally applied in vertical columns, or staulches, to the side of the ladder. Once the thatch is on, the eaves are cut and rodded. The ridge is then applied and the whole thatch is encased in thatching wire to prevent vermin damage.
Although the ridge will need replaceing every 10-15 years, the main body of long straw thatch should last between 25 and 40 years with due care and maintenance.
Combed wheat reed
This style of thatching is perhaps the most modern. A comber is fitted to the threshing machine, which cleans most of the flag off of the straw stems. The straw is normally fixed to a bottom coat with hazel spars in a similar fashion to long straw. One difference between the two styles is that the straw is dressed into place using a legget, rather than dressing by hand. The finish resembles that of a water reed roof. No rod work is fixed around the eves. Combed wheat reed is most common in the south west of the country.
The whole thatch is encased in wire netting to prevent vermin damage. Again, the ridge will need replacing every 10-15 years, but the main body may well last slightly longer than that of long straw.
When re-thatching with water reed it is most common to strip off the remnants of the old thatch entirely. The new thatch is held onto the roof using steel rods, or sways. Steel rod has the advantage of not rotting, years ago lengths of hazel would have been used for the job. The sways run horizontally along the rafters and are held in place using spikes which are driven into the rafters. Unlike the previous two methods, the thatch is laid on in horizontal courses instead of vertical columns. A legett is used to dress the reeds into place.
A straw or sedge ridge is usually used to finish off a water reed thatch. Again the entire thatch is normally wired. Again, the ridge will need replacing every 10-15 years, but the main body of the thatch should last 40-50 years.