Walls often contain a variety of openings. Margaret Brooks (1973) considers these in some detail for the West Riding of Yorkshire. Apart from gateways and stiles, there are two main types of openings. These are the small ‘water smoots’ or ‘rabbit smoots’, and the larger ‘cripple holes’.
Cripple holes, also known as ‘hogg holes’, ‘thawls’, ‘thirl holes’, ‘smout holes’, ‘sheep runs’, ‘sheep creeps’, ‘sheep smooses’ and ‘lunky holes’, are built large enough to let sheep through, but are too small for cattle. If located carefully, they increase the flexibility of the grazing enclosed, as sheep can be allowed to graze through fields which contain cattle, without opening any gates. At other times they can be blocked off to make them impassable. For moving a big flock more quickly, two cripple holes are sometimes built side by side.
Another interesting use for cripple holes is found on the Isle of Noss, Shetland. Here the holes are designed to let sheep through to graze the cliffs, while being impassable to Shetland ponies.
Smoots allow water to flow freely through walls which are built in hollows, or along the contours of a hillside. Smoots not obviously sited for drainage may have been constructed to allow rabbits through the wall. This may have been to discourage burrowing and damage to the wall, or for the purposes of snaring or trapping. Another theory is that in some cases the holes had to be built to allow rabbits free access to properties which held pre-Enclosure game rights. Rabbits formed an important part of the rural diet up until the mid 20th century. Many walls contain rows of smoots often only a few metres apart. A good example is a wall at the top of a slope near Barnsfold Farm, Hayfield, where once a year rabbits were driven up the slope and through the smoots into nets.
Rollinson (1972) shows a diagram of an interesting rabbit smoot and trap at Ayside, Cartmel, which has a stone lined pit to one side of the smoot. The pit would have been covered with a counterweighted wooden trap door, which swung as the rabbit stepped on it, trapping it in the pit.
Other smoots for trapping animals were built either diagonally through the wall, or offset, to prevent the animal seeing the trap on the other side. These are more complicated to build than straight smoots, because good stonework is needed to provide a strong inner face to the smoot and hold the hearting in place. Unless the walling stone is very regular, such as Cotswold stone, offset smoots are best built using single large stones, which form both the face of the wall and the inner face of the smoot.
Today’s smoots are most likely to be built to enable wildlife to pass through the wall, or to maintain a tradition. New smoots are still built for trapping on shooting estates. These are usually about 7″ (180mm) square to trap weasels or stoats, or 12″ (300mm) square to trap foxes, and offset so the fox cannot see the trap through the smoot.
Other unusual openings are sometimes found for which there is no easy explanation. Margaret Brooks (1973) describes the ‘mystery holes’ which occur along several walls at World End, near Keighley. These are identical to smoots, but located midway up the wall. Among the ideas offered by wallers and country people for these holes is that they were built to shoot through, to relieve the walls of wind or water pressure in times of storm or flood, to allow rabbits to run through on top of drifts of snow, to allow snowbound sheep to breathe through the wall, to provide a place to lodge blocks of salt or the farmer’s lunch or wooden beams for a low structure. None of these explanations, serious or not, seems satisfactory for the number of holes concerned.
Raised smoots are sometimes found opposite each other on either side of a road. A suggestion that these were constructed by the Home Guard during the war to take poles to block the road is likely to be another apocryphal story.
It is not always easy to be sure why an existing smoot has been built, and the local name does not necessarily determine the original purpose. The location is the best clue. Holes in walls up and down slope have no drainage purpose, so were probably built for animals. Holes in walls across slopes were probably constructed for drainage, especially in high rainfall areas such as the Lake District. In limestone country, drainage into the subsoil is so fast there is little need for water smoots, whatever the alignment of the wall.
Small smoots are also built to bridge tree roots, which may otherwise damage the wall.
Cripple holes
Cripple holes, built to control the passage of sheep through the wall, are constructed in the same way as large water smoots. Dimensions are normally about 1’6″-2′ (450-600mm) wide by 2′ (600mm) high, but there can be considerable variation. As sheep breeds tend to be larger than they used to be, traditional cripple holes may not be big enough. When rebuilding an existing cripple hole, the size will probably be limited by the length of the original lintel.
In Scotland, according to Prevost (1957), these holes are often built narrower at the base than at the middle and top.
The following drawing (adapted from Wood, 1973) shows an unusual hole in a wall in Grassington, North Yorkshire. The wedge-shaped opening is built so that lintel stones can be placed securely across to form an ordinary cripple hole. The stones above are added loosely so that they and the lintels can be removed when necessary to form a full-height ‘cattle creep’.
Occasionally you may even come across a cripple hole that has been bridged with an arch, in the absence of suitable lintels. Arches are described further in chapter 10.
As cripple holes do not provide convenient access for shepherds, stiles are sometimes built alongside.
Procedure
A cripple hole is effectively two low wall heads or piers, with a single slab or pair of narrower lintels forming the roof. Hence any of the patterns for building a wall head can be used.
Care needs to be taken in selecting lintels. They should be as long as possible, to bind well into the wall on either side, and at least 4″ (100mm) thick in order to support the wall above. Many old cripple holes have failed because the lintel has cracked. If a thinner lintel has to be used, or the wall above is over 6′ (1.8m) high, you may need to consider some of ideas given below.
There are a number of ways to floor a large opening. Turf is quick and easy, but with frequent use may get worn away, causing the sides of the opening to settle or collapse. A better option is to continue the foundation trench through the smoot or cripple hole, and floor it with large flat footings or slabs to ground level. You need to choose and position the slabs with care, pairing them as necessary, so that the weight of the wall is distributed evenly.
If large, slab shaped footings are not available, the rest of the floor can be filled with smaller stones, which should be set with their long axis down into the ground, and tightly wedged together. Use the biggest stones across the opening on the downhill side, to protect it from erosion by water and stock. The stones should be set with the flattest face upwards, to create a reasonably level surface. This technique, called pitching or cobbling, is fully described in Footpaths – Stone pitching.
Construct the wall heads the required distance apart, keeping the inside faces as smooth as possible so there are no projections on which stock could catch, destabilising the wall. There is some debate as to whether the piers should be finished with runners or tie-stones. Each can present problems, and the choice is usually dictated by the stone available.
If you are using two narrow lintels it is probably best to end the piers with tie stones, so that you are not placing one ‘traced’ stone on top of another. Select tie stones which will not form running joints with the ends of the lintels. If you are using a single slab lintel, end the piers with two runners, as the lintel will act as a tie, and the problem of running joints will be avoided.
Place the lintel or lintels on the two piers, with an equal overlap on either side, and taking great care not to dislodge the top layers of the piers. Place one end on one pier first, and gently lower the other end into place. Larger lintels may require three or more pairs of hands. For information on manoeuvring large stones, see here.
Where a pair of lintels has been used they should touch along the centre of the wall, and be tied together with at least one through directly on top of them. If there are any gaps, they should be well bridged with flat hearting, to prevent other hearting falling through. Don’t simply plug the gaps with hearting, as it will get pressed down by the weight of the wall above, forcing the two lintels apart.
Small animal smoots
Small animal smoots vary greatly in size, depending on their purpose and probably also on the available stone. There are set sizes for traps (see above), but for wildlife conservation it’s probably best to consult with local wildlife experts about requirements for the locality. Small smoots for rabbits, hares and other small animals are normally about 4″ (100mm) wide and from 10-18″ (250-450mm) high. Badger smoots should be about 7-8″ (180-200mm) wide and 12″ (300mm) high.
Procedure
- Lay the foundations for the wall, choosing footing stones for the smoot which form a complementary pair, are even topped and set to finish at ground level. Ideally they should be about 6″ (150mm) wider than the smoot, to allow a 3″ (75mm) overlap on either side to help prevent erosion.
- Build up the sides of the smoot as miniature wall heads, which requires just one or two good stones on either side, which should have good length into the wall. Don’t construct the smoot by simply omitting a few stones from the base course, as this exposes and weakens the wall’s centre.
- Bridge the smoot as described for cripple holes. This will normally require two lintels, as the wall will still be quite wide at this height. They must be at least 6″ (150mm) thick to support the weight of stone above. Methods for ‘strengthening’ lintels are described below.
- Tie the lintels together and bridge any gaps as described for cripple holes, and then continue the wall to the top.
Water smoots
Water smoots are built to allow the passage of streams or ditches through dry stone walls. Finding suitable lintels to span the width of the ditch can be a problem. The size of the available lintel stones largely determines the width of the watercourse that can be spanned, and consequently you often find heavy iron bars or old axles, or wooden rails or sleepers used instead. The results tend to be short lived. Sheet metal should definitely not be used as it quickly rusts and bends. Sections of large diameter concrete pipe can be used, turning the smoot into a culvert. For more details on culverts, see Footpaths – Culverts.
Water smoots are built in the same way as cripple holes and smaller smoots, but bear in mind the following:
- Make sure that the foundations of a large water smoot extend to the bottom of the ditch or stream, or erosion will occur, causing collapse of the smoot.
- The width will be limited by the lintels available, although double smoots can be built as shown below. The height should give sufficient clearance for seasonal flood levels. Exceptional floods may well cause damage.
- Smoots require checking from time to time to clear any accumulated debris. Smoots which incorporate a water gate or bars require more frequent checking.
- Large boulders set into the bank on the upstream side of the smoot will help protect the sides of the smoot from erosion. If there are sufficient boulders, protect the downstream side in the same way.
Wide spans
For wide shallow streams, a series of piers or pillars can be built, bridged by separate lintels. The pillars must be set on deep and solid foundations to resist erosion.
Smoot and bar
Another method of increasing the capacity of the smoot is to build a high smoot with a stone slab or bar through the centre of it. This permits extra flow, while still being sheep proof.
This example, using a thin slate across the centre, is in a single stone wall at Blaen y Nant Farm, Nant Ffrancon, North Wales. As it is not weight bearing, the thin stone is not a problem, and it is less of an impediment to water flow. This technique can also be used where you need to make a smoot, but don’t have a sufficiently strong lintel to carry much weight of stone above. Note the boulders that have been dug in to protect the smoot.
Strengthening lintels
Triangular lintels
This is a method of strengthening a lintel where the lintel itself is rather thin, or where the weight of stones above is heavier than normal. The use of triangular stones to displace the forces over lintels is an ancient technique, used by the Mycenaen Greeks over 3000 years ago.
Triangular lintels were also used by the builders of some of the Scottish Brochs, which are fortifications that date back to the Iron Age. The example shown, at Dun Dornaigil, Scotland, still has around 20 foot of stonework remaining above it.
To use this technique over a smoot in a dry stone wall requires a triangular stone. Ideally the stone should be regular and overlap the piers, but narrower or less regular triangular stones will help to a lesser extent. As the triangular stone takes the place of a through which would normally link the lintels, throughs should be placed adjacent to the triangular stone to compensate.
The smoot with a bar, shown above, is another way of improvising where you don’t have a strong enough lintel to support the full weight of the wall above. A weaker lintel, sufficient to support a few upper courses is used, higher up than required for the smoot, which is made stockproof with a slab or bar.
These techniques are not common, but are methods which can be borne in mind and added to a waller’s problem-solving arsenal.
Cantilever lintels
Another method of strengthening a lintel is to place further long stones bridging from the main body of the wall over the lintel.
The cantilever lintels should be anchored into the wall by at least half their length. If possible they should meet in the middle, but if not, use a suitable stone to fill the gap. Another long stone can then be placed on top to further dissipate the forces.
As with triangular lintels, this method compromises the use of throughs. It also has the drawback that traced stones are used on top of each other, and if these are narrow an unstable structure may result. Place throughs at the first opportunity.
