A Guide to Traditional and Modern Thatch Roof Materials
There are lots of things about thatched roofs that property owners appreciate, not the least of which is that the roofing materials are natural. Since the earliest days of thatched roofs, thatchers have used a variety of wild grasses, shrubs, straw, and other plant material to work their magic. And although the choice of thatched roof materials may be a bit more limited these days, the quality of finished roofs has not diminished.
The materials chosen for a thatched roof are key to the roof's insulating and moisture-resistant properties. That means thatchers must choose carefully. Not every species of plant is suitable as a roofing material, especially in our climate that can be extreme from season to season. Today, the most commonly used thatched roof materials are long straw, combed wheat reed, and water reed. Let's look at each one in more detail.
What we commonly refer to as long straw has been among the most used thatching materials in England for centuries. This product is manufactured by cutting low on the plant and binding the resulting material into large, tight sheaves. Long straw is a combination of wheat and rye in most cases; barley and oats may be used as well.
Before long straw is suitable as a thatching material, it must be cut, bound and ripened. This is all done in the field. Afterwards, the material is stored until it's time to thresh. Threshing removes the actual grain from the stalk to leave only the straw. It must be done carefully to avoid extensive bruising that could reduce the life of the straw as a roofing material.
Once the straw is finally ready for bundling, it is pulled from the main pile piece by piece and drawn into the bundle. No effort is made to create any kind of uniformity, as doing so would reduce the insulating and moisture-resistant properties of the resulting thatch. Instead, random pieces of straw are gathered together, bound, and trimmed without any regard for length or orientation.
Combed Wheat Reed
This thatched roof material is sometimes known as Devon Reed due to the fact that the county of Devon offers one of the best environments for producing it. Combed wheat reed offers a very distinct look and texture that has made the Devon Reed thatching design one of the most recognised in the UK.
Combed wheat reed is actually made up of the same material used for long straw. What's different is the way stalks are processed. After cutting and ripening, the material is tied into small bundles just as long straw is, but with one exception: the ends are aligned so that all the ears are lying in the same direction. This creates a unique finished product at threshing; a product with a large base and finer top.
The threshing process involves treating only the ears of the stalks to remove the grain. This prevents any bruising that might otherwise occur with a less gentle threshing. Thrashed stalks are then combed using a machine that does to the straw what you do when combing your hair. Combing creates a clean, uniform bundle of thatched roof material that is rather impressive to look at.
Water reed is a specific kind of wetland plant that wasn't one of the preferred thatched roof materials prior to the 19th century. Thatchers began using it when mechanised agriculture encouraged farmers to grow more short stalk grains that were unsuitable for thatch. Now water reed is just as common among thatchers as long straw and combed wheat reed.
In terms of the plant itself, water reed is a hollow plant that flourishes in wet conditions. When it's ready to be harvested for roofing, it is cut low on the stem just like the other materials. Cut reeds are then sorted by length and put into bundles. This sorting is important to the eventual thatching process. Longer bundles are used closer to the eaves while shorter bundles are laid closer to the ridge.
One of the advantages of water reed is its stiffness. The extra rigidity of the stalks means less structure is required underneath as a support system for the roof. At the same time, the hollow nature of water reed makes it extremely lightweight and easy to work with.
Roof Designs and Local Regulations
Water reed is the preferred thatched roofing material for generic applications. Today's builders and thatchers mostly use imported water reed because it is less susceptible to damage from the agricultural practices of modern-day Britain. Water reed is ideal for new construction where straight lines and sharp edges are preferred. That said, long straw and combed wheat reed are still used as well.
In areas where local regulations require thatchers to maintain distinctive styles, these other two materials are preferred. In Devon, for example, the thousands of listed structures in that county could only receive new roofs made of combed wheat reed.
The idea behind requiring specific thatched roof materials is to maintain the historical integrity of the local region. Planners want new roofs to reflect what thatchers did in the past so as to remain true to the area. That said, some regions allow new builds to use an assortment of materials and designs while others require new builds to conform to regional styles.
Less Used Thatched Roof Materials
When no rules or guidance are in play, thatchers may choose to use something entirely different. For example, sedge may be chosen as the exclusive material for a new roof or combined with water reed to create a different appearance. Sedge is another wetland plant with leaves that are razor-sharp. Thatchers like it as ridge material because it is easy to cut, shape, and define. It's not uncommon for thatchers to make the main roof structure out of water reed but use sedge for a block bridge.
Other less used thatched roof materials include:
Heather – Heather is a perennial shrub that grows extremely well across Europe in acidic soils. The heathlands and moors of the UK have an abundance of this plant. It was once the thatched roof material of choice in north-east England and Scotland where wheat was hard to come by.
Gorse – Gorse is a thorny shrub that grows well in sunny areas and places where the soil is sandier. Though used only occasionally today as a thatched roof material, it was very popular in the south-east of England prior to the Industrial Revolution.
Bracken – Bracken is a species of fern that grows abundantly on the moors of south-west England. It was chosen as a thatched roof material because of its strength and ease of use. It is still used today in some areas where regional styles call for it. But like gorse, bracken requires a bit of extra skill to work with.
The most important thing to know about these thatched roof materials is this: when skilfully crafted by master thatchers, each of them can be turned into a magnificent roof that provides exceptional insulation, weather resistance, and an incredible look that cannot be matched by any other building material. The key for homeowners is to find a skilled craftsman capable of working with the preferred material.
Availability of Materials
Beyond the look and feel of various thatched roof materials, thatchers also have to be concerned about availability. There are no regulatory standards defining the quality of thatching materials either. So craftsmen have to be choosy about what they select for their work. This is why so many are turning to imported water reed rather than relying on domestic products.
One last thing to know about materials is that thatchers generally prefer to supply their own. While a craftsman may be skilled in working with numerous materials, he may prefer one over the rest. Thatchers and their clients must work out between them what kinds of materials will be used to complete a project.
The thatched roofs of centuries gone by remain today thanks to the quality of thatched roof materials. A well-maintained roof made with high-quality materials can last for decades, and then only minor repairs can keep the roof going for a little while longer. When it comes time for complete re-roof, using high-quality materials ensures a new thatched roof that will last for decades.