Ridging a Thatched roof… with straw, grass, mortar & timber


All standard coatwork needs a covering at it’s apex; to protect the final line of fixings and top course of thatch. Over time, various ways of achieving this have been developed… The vast majority of standard thatched roofs, in Britain, are now topped with a ridge; of either cereal straw or sedge grass. As will be seen, this was not always such a popular finish, to a thatched roof.

This type of ridge needs renewing throughout a thatch’s life; as well as finishing a new roof; the methods for completing either being the same. Renewing existing ridges, gives much work to the thatcher.

Straw and grass ridges…

Old photographs reveal that most roofs were once very simply ridged. The ‘chocolate box’ effect, with an ornamental ridge, was rare in most parts of Britain. A reason why this type of ridge is disliked by many local conservation officers. Outside of the water reed areas of East Anglia, where ornate ridging probably originated; few thatches enjoyed such treatment. But since the 1960’s, thatchers have created a whole host of differing patterns and designs. In fact, the ornate ridge of straw or sedge grass, is probably the only aspect of the craft, that is found in Britain and nowhere else in the world…


The onward march of the ornate ridge… Outwardly this pretty Cheshire cottage, at Burton; seems to have changed little in a century, apart from the ridge. Incidentally this cottage was the birthplace of one Thomas Wilson, in 1663. Who rose to be Bishop of the Isle of Man…


Both simple and ornate ridges last around the same length of time… A ridge comes to the end of it’s useful life, when the wooden fixings holding it on, decay. What lies underneath those fixings, makes little difference. The cost of ridging lies mainly in the labour to create it. A thatcher can often cover around 25 feet (7.5m.), of a simple ridge, in a day… A really ornate job, could take five times as long.

There are two methods of ridging; Butts Up Ridging and Wrap Over Ridging; which determine how the very top section of a ridge is covered. And two ways of finishing a ridge; Block Finish and Flush Finish. Either of these determines the appearance of the bottom section of the ridge. The names are almost self explanatory…

thatch at chideock dorset

thatching at swollowfield berkshire

The upper thatch is topped with a butts up flush ridge, which forms a seamless join with the coatwork. The lower roof, by a wrap over block ridge, immaculately shaped into a pleasing design… Top thatch; at Chideock in Dorset. Lower thatch; at Swallowfield in Berkshire.


Butts up ridging, consists of a layer of combed wheat reed, with the bottom butts upwards. As only this material can be used, for this type of ridging, it is mainly found in the home of combed wheat reed; in the West Country. The other, more widely used wrap over method; uses either long straw, combed wheat reed or sedge grass. Literally being wrapped over, the apex of the roof… Either of these ridging methods, can be completed, with either Block or Flush finishes. It is common practice, to create a block ridge on the front of a property and ridge the rear slope, with a cheaper flush finish…

The flush finish, consists of shaving down the ridge, at the bottom; joining invisibly with the coatwork. The block finish is created, when the thatcher fixes an extra layer of material, before the top ridge section is fixed; known as a Skirt. The thatcher shapes the skirt, to a rough outline of the finished design; which is eventually cut from it.

All these types of ridging also use thatching spars, usually in great numbers; and liggers. The liggers hold the straw or grass in place and twisted spars hold down the liggers… A thatcher typically spars the liggers into place, every 4 inches (100 mm) or so, along their length. Untwisted spars also double up as a means of decoration, as Cross Spars on most ridges. The thatcher below is sparring down one side, of a butts up flush ridge; yet to be filled with cross spars and trimmed.

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Ends… The upper ridge, from Hertfordshire, shows the attractive peaked, ‘pinicale’ finish that is found throughout the eastern counties of England. Nearly always ending a wrap over ridge, in either long straw or sedge grass. The centre capped end is common wherever wrap over ridging is found. The right ridge, from Somerset, shows a typical ‘Dorset Point’, formed, when excess material is pulled forward, on a butts up ridge. The term Dorset Point is used in Devon; they don’t seem to have a name in Dorset…

devon thatch

Whimsical ends… The above from Devon, the left from Middlesex… Allowing the thatcher to personalise their work and add a little humour to the craft…

Ridging… The working methods.



A ridge will both last longer and look better, if it is not too flat… Apart from creating enough springing, a reason for the addition of the three ridge rolls, at the top of the roof; is to form a steep enough coatwork angle, for the ridge to sit on… Ideally, when completed the ridge should be at the same angle as the coatwork. If re-ridging an existing thatch, the thatcher will need to see that the top of the roof is brought up to the correct level. This may mean building up the ridge roll once more; or even rethatching the top course, if the ridge has been allowed to decay a little too long. The thatcher then fixes the ridge, as follows…

The block finish…
With this type, the base layer or skirt is fixed first… To form this skirt, the thatcher spars on a layer of material, around half the thickness of a normal coatwork course; at a suitable distance down the roof. If the ridge is wider than the material used, another layer is fixed, to fill in the ridge up to the apex of the roof. The third ridge roll is now also fixed, giving a firm level base for the top ridging; either butts up or wrap over… The ridge is normally cut to shape, when this top layer has been added and the spar work has been completed. A very sharp knife is normally used, for this skilful cutting.

Two types of block finish can be created… One type consists of a simple straight line; giving a Straight Block Ridge. But if the skirt is shaped to have a pattern cut from it; the result is it an Ornamental Block Ridge. If an ornamental block ridge is to be created, the thatcher will need to measure the roof; and work out the sequence and distance, if any, between the desired patterns. An odd number of patterns always seem to look better than an even number…

thatch at long sutton somerset

thatching at wroxeter shropshire

Patterns… Ornamental ridges, can have a continuous pattern, as the ridge, at Wroxeter in Shropshire, shows. Or have each pattern spaced along the roof, as the top cottage, near Long Sutton in Somerset, demonstrates. Thatchers have devised very wide variations to both types…

thatch in chumleigh devon

thatching at merthyr mawr glamorgan

Dead straight… The upper straight block ridge, at Chumleigh in Devon; needed skill to keep such a true line over a long ridge… The right ridge at Merthyr Mawr in Glamorgan; is also a straight block, but cleverly incorporates a central chimney in the design. Both ridges use the butts up method, combed wheat reed being the traditional material, in both counties…

The flush finish…
Usually no skirt is required for this finish…This type is also known as a Shear Out ridge. As a shearing hook is often used; to trim the edge smoothly into the top of the coatwork, when the ridge is complete… It is good working practice that the join, between the ridge and coatwork should be invisible. Typically the ridge is trimmed, from under the lowest ligger to the top edge of the coatwork face.
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No join… This flush ridge, in combed wheat, sits well on top of a coat of water reed. Only the colours of the differing materials, show where the ridge ends and the coatwork begins…

With any base layers in place, one of the two methods of ridging is now employed; to cover the final ridge roll and complete the ridge…

The wrap over ridging method…

These are also known as Turn Over Ridges… A base layer of material is firstly fixed. This is formed by knuckling over the tops of large handfuls of thatch. Then sparing them on, just under the third ridge roll, along both sides of the ridge… The thatcher then takes handfuls of material, splits them in half and lays one half over the other, head to toe. These are then folded in the middle, and placed over the ridge roll and down over the base layer. These wrapped over handfuls are kept tight to each other, often with the aid of reeding pins. As the work progresses, a ligger is sparred down, at the apex, into the ridge roll; to hold these handfuls in place. This top wrapped layer should be between 4 and 6 inches (100 /150mm) thick, over the ridge roll… When a section has been completed, the appropriate liggers can be sparred on, to the desired design…

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Wrapping… Two thatchers can work well together whilst completing a wrap over ridge. The photo shows the ridge roll, with the knuckled base layer in place, on either side. The top wrapped layer is then laid and fixed down over these.


Rope Top Ridges…

A variation, on the standard wrap over method, is the rope top design. Again the name is fairly self explanatory. These tended to pop up almost anywhere, from Leicestershire to Cumberlandand and were once very common in Wales. They are now found in large parts of Ireland; in areas of South Devon and once more in parts of Wales

The top is given a twisted effect, by taking a hand full of material, splitting it, as with a wrap over ridge; then twisting it around a finger. The knots or bobbins, are then threaded on a spar. An end for the knots, which seems unique to Devon, can be created by tying a double handful of material just under the ears… Being completed, by plating a few stalks at a time, one over another… When trimmed a small pineapple effect is created, giving an attractive finish.


South Devon roping… Only this area seems to have devised a neat plaited end for rope top riding… When done well, as in the right ridge at Kingsteignton; a very attractive topping can be created, either with a flush or ornate finish.

thatch dyserth wales

thatch newton linford

Old roping… Rope top ridges were once seen over a great part of Wales and to a lesser extent, in neighbouring parts of England. The heavily repaired top thatch, from Dyserth in Denbighshire, is very typical. The Leicestershire cottage, at Newton Lindford, also shows this type of ridge. Along with what seems to be the original design, for the ornamental block ridge… This ‘saw tooth’ pattern is often seen on old images of thatch; dating well back into the nineteenth century. But these were always few in number; compared with flush finished ridges.

 

Butts up ridging…

thickness of butt ridgeOnly combed wheat reed is suitable for this method; as it relies on the stiffness of the thatch to work effectively… With any skirt in place, the thatcher takes large handfuls of wheat reed, butts the ends level and lays them with the bottom upwards; around 4 inches (100 mm) above the ridge roll; as shown opposite. This wheat reed is held temporarily, until a section can be tapped level and a vertical face created; above the ridge roll. The opposite side of the ridge will fit against this… A correct thickness will be achieved, if a good sized wheat reed bundle covers around 3 feet (900 mm), of one side of the ridge. When a section is has been laid, the ridge can be sparred down to the desired design and trimmed.

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Butts up ridging… At Selworthy around 1910. The ridging is very similar to modern work, except these Somerset chaps only used one ligger to hold down the majority of their ridging… As the image of their completed job shows. The ‘Dorset Points’ are traditionally more pronounced, in this area than in many other combed wheat reed districts.

Ridging under chimneys, windows; etc…
Whatever material is being used, the same procedures apply; where a ridge is needed under a window, or chimney… It is better to have laid and fixed the main ridge, on either side of the feature. So that if possible, this new section of ridge can be shaped and fixed, to form a continuous part of the main ridge. Any skirt required is fixed as normal. This is followed by filling the remaining area, with knuckled up handfuls of thatch; up against the chimney or window bottom, until it reaches the correct level… Extra life is often given to these areas of ridge, by the use of decent sized mortar or lead fillets and aprons… As these areas receive a lot of wear, great care should be taken, when fixing the ridge into place with spars… They should be as uphill as possible. If a job has a leak, it is nearly always caused by a spar drawing water in around a chimney… In fact it is good practice that all spars on a ridge, away from the very top; are driven to shed water and not attract it.

thatch church norfolk

Knuckling up… A long new roof and ridge for the Norfolk church of St Mary’s, at Sisland. The main roof is topped by a wrap over straight block ridge; in sedge grass. Which is in the process of being ‘cross sparred’. Under the tower however the sedge has been knuckled up tight to the tower boarding.


thatch sulgrave nothamptonshire

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thatching devon

Variations… As ever with the craft, there are many. These old photos show that this has been going on for generations. The top thatch, from Sulgrave in Northamptonshire; seems to have a very wide ridge indeed… It is in fact a shaped part of the coatwork, complete with long straw decoration. Similar to the cottage in the middle image, from East Anglia…The bottom cottage, near Ilfracombe in Devon, shows the passing vogue for spar decoration’; on the apex of the roof. Quite a common sight in this area, for a few decades, in early twentieth century…

All types of organic ridging will benefit, if they are covered with wire netting; when the wooden fixings do weaken, the wire will help keep things together, for a while longer. Even on the most basic flush ridge, this addition is still cost effective…

Non Organic Ridging… With mortar, timber and tile…

The traditional ridging, in the northern half of Britain and the Channel Islands; mainly consisted of materials, other than straw and sedge grass; until quite recently… Tiles and mortar, along with timber, are still used in parts of Scotland. But as many old pictures, of the relevant areas illustrate, these types of ridge, along with turf; were once common as far south as the North Midlands. And for a while straw and sedge were in retreat, over a much larger area…

Around 1900, Portland cement became readily available, at a reasonable price. And thatchers, well away from the traditional mortar areas, started using this material. Ridge tiles also seem to have had a widespread use, on the very top of many thatches. The reason why straw and sedge ridging came under threat, is that the craft of domestic thatching, was in steep decline. A cheap and quick ridge of cement mortar; or a line of large ridge tiles, would have appealed to many thatchowners. And there were no conservation officers to say otherwise… I have often come across, what must be the remains of this short lived fashion. Fragments of old cement mortar, mostly made with ashes; buried under layers of old ridge…

The revival of the craft’s popularity, ensured that mortar and cement were eventually banished, to a thin fillet around the chimney; on roofs over most of Britain. Even on roofs in the North of England, the ubiquitous ornamental block ridge, now holds sway…

thatch swanston edinburgh scotland

thatch sark channel islands

Traditional mortar ridging… At either ends of Britain. The top cottages, at Swanston just outside Edinburgh; sport a neat mortar ridge. A normal ridging material hereabouts, along with tile, turf and timber. The other buildings lay far to the south…This is the Island of Sark, a century ago. Along with the other Channel Islands, a ridge of mortar, based on the local ‘Loess’ clay; finished most thatched buildings. The Sark cottage on the right, seems to be ready for just such a ridge. The object stuck in the roof, is a little harrow; used in the island’s small fields. It’s spiked side seems to have doubled up, as a thatcher’s standing biddle…


thatch lincolnshire
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Tiles old and new… The top cottage, at Harrington in Lincolnshire, shows an old tiled ridge; once often seen in this county… But straw and sedge grass are mostly used today. The lower cottage is well outside the traditional area, for this type of ridging; at East Quantockshead, in Somerset. An estate who own several thatches in this area, thought this would be the end of all further ridging expenses. Much to the local conservation department’s chagrin… Straw is now being used once more, as the right of the cottage shows. The large tiles came from Holland, where this method of ridging is very common…


thatch melrose scotland

thatch kirkoswold scotland

Timber old and new… Timber boarding makes a quick and easy ridging material, but seems to have always been confined to use in Southern Scotland. The old top image, shows a long gone roof, at Melrose in Roxburghshire. The well known thatch, at Kirkoswold, in Ayrshire, is below. Both have a wooden ridge, consisting of three overlapping boards, on each elevation. A simple and low maintenance finish, to their thatch coatwork… The lower cottage, was built in 1786 by a friend of Robert Burns. The ‘Souter Johnnie’ of his famous poem ‘Tam o’Shanter.

Turf ridging was examined in a page included in the Materials and Tools section. Clay ridging appears in the page on Non Standard Thatching…

Timber, tile and mortar ridges… The working methods.
Tiles and mortar are easy enough to fix; lying in the realm of the builder, as much as the thatcher… With a line of ridge tiles, as the final topping, the coatwork face needs to be brought much farther up the roof. Thus allowing the tiles to cover the whole ridge. The tiles lie in a bed of mortar…

A topping of cement mortar can cover any width of ridge, and is often spread over wire netting; which helps reinforce and hold the ridge in one piece…

The overlapping lengths of boarding, on a timber ridge, are fixed onto an underlying wooden frame. This is fixed into the top of the thatch coatwork, often by spikes. As with a cement mortar ridge, any width can be accommodated…