This is an ancient technique for building paths and roads, which has seen a revival since the early 1980s, and is now being used on many paths in the Lake District, Snowdonia, Peak District, North York Moors, Yorkshire Dales and in Scotland. It is a skill akin to dry stone walling, using the local stone in the most effective way possible. Pitchers, like wallers, regard it as something of a challenge to produce a functional structure using only the materials to hand, with no mortar, plastic pipes or other man-made materials. The aim is to combine pitching with restoration techniques on eroded areas to produce, within a few weeks, a path that looks as if has been there for centuries.
Regional styles are developing, reflecting the type of stone available, the ground conditions, and the skills being handed on in each area. Pitching is arduous work even in good weather conditions, and work on high or remote sites may involve a long walk each day to the work site. Pitching work on the mountains of North Wales and the Lake District stops during the worst winter months, with teams working instead on low level paths. Where competitive tendering procedures are used, such as in Scotland, path contractors have little freedom to plan work seasonally.
The basic technique involves setting large stones with their long axis into the ground, packed tight together and wedged with smaller stones as necessary. The size of the stone depends on what’s available, the only requirement being that the stone should have a reasonably level ‘top’ face to make the walking surface.
The details below notwithstanding, the best way to learn stone pitching is by doing it. Skills and experience have built up over the last decade with many people permanently employed doing stone pitching and associated work in the Lake District, Snowdonia and elsewhere. Volunteers still have a part to play, and regular projects are run in the Lake District, with expert pitchers working alongside volunteers for the first couple of days of a project.
In all areas, pitching is seen as a means to an end: that end being the restoration of the hillside and the prevention of further erosion. There are still many years of work ahead merely to repair existing damage, and rarely is there the opportunity or need to pitch a path across an undamaged hillside. However, most authorities are now confident that they have the skills and experience to cope with most situations. Pitching is almost always done as part of a larger scheme for restoration which will include drainage, vegetation restoration and other work.
Sources of stone
Ideally, the stone can be gathered from near the path, but normally will need to be gathered from scree or boulder fields which may be some distance away. The distance and ease of transport is the most important factor affecting the speed by which work can be done. Various techniques can be used to ease the transport of stone over steep, rough ground. Where insufficient stone is available on the hillside, supplies can be brought in by vehicle or airlift.
When gathering stone off the hillside, one needs to be careful not to totally clear an area so that when viewed from a distance, the completed pitched path climbs up a strip of hillside devoid of stones, noticeably different from the scattered distribution of stones on the rest of the hillside. Try to leave a natural looking distribution, which blends with other areas on the hillside.
A hole or ‘nest’ left by the removal of a stone from turf should be repaired so that it doesn’t show, or become a point for erosion to start. Normally the nest can be repaired by simply treading down the side of the turf. Large nests will need refilling with spoil or small stones, taken from the path, stream side or other location nearby. The filled nest can then be seeded as desired.
Screes or boulder fields normally have ample supplies of stone, which can be removed without fear of initiating erosion. Some stone can be gathered from streams. In storm conditions mountain streams can bring down large quantities of stone, so some can be taken without fear of erosion resulting.
Normally walls should never be used as a source of stone, however dilapidated they are. However, dilapidated walls are in effect like a causeway, and may provide a strong, raised sub-base for a path across wet or fragile ground. Where the line provides a useful route, the landscape may be better served by using the walling stone to build a pitched path along the existing wall base.
Type of ground
Pitching is best used on slopes of between 10-20 degrees, although slopes up to 25 degrees can be successfully pitched. It is not normally appropriate for flat or gently sloping ground with short vegetation, which walkers are likely to find more comfortable than the pitched path.
Pitched paths on slopes should take a natural line, climbing steep sections as necessary by increasing the rise between each stone. Sharp hairpin bends and zigzags are best avoided, as these are difficult to construct, and short cuts often develop. Amore direct line, though steeper, is usually more likely to be kept to by walkers.
Pitching requires a solid sub-grade. Normally pitching will be done on rocky hillsides with very thin soils, if any, covering the rocky sub-grade, with bedrock exposed in some places. Where shallow peat, up to about 300mm deep, is present on gentle slopes or flatter areas it can be removed along the line of the path. Deep peat that needs to be crossed will require a floating flagstone or aggregate path, or a boardwalk.
Rates of work
The rate of work depends on the nearness of the stone supply, the size and shape of stone, the width of the finished path, the conditions on the slope, and the weather. Experienced contractors will work faster than volunteers. On volunteer projects, a rate of one square metre per volunteer per day is average, including the time taken to gather stone. Experienced pitchers should average two square metres a day. Contractors working with airlifted stone can achieve three to four metres a day.
Transport of stone
Pitching can be difficult and hazardous work, as it involves moving large stones on steep or eroded hillsides. Great care must be taken by the workers both for their own safety, and for the safety of walkers below them on the hillside. The methods described below allow larger, more effective stone to be used, and also minimise damage to the ground compared with carrying or dragging stone. Supervision by an experienced person is essential.
- Power carriers. These are tracked barrows, powered by a 4 or 5.5 horsepower engine, useful for moving pitching stone over steep and rough ground.
- Wheelbarrow sledge. This is simply a wheelbarrow body with the wheel and legs removed, attached to wooden runners. This is used with a pulley system to move stone up or down a slope. The pulley is attached to an anchor, made of three stakes or crowbars stuck in the ground and lashed together. One person guides the sledge, while two people act as motive power and brake at the other end of the rope. Keep walkers and volunteers well out of range while the loaded sledge is being moved.
- Scaffold barrow run. The National Trust’s Carneddau footpath team in North Wales sometimes use a temporary barrow run of scaffold poles and planks to move stone across slopes. They find it well worth the time and effort of spending, for example, two days erecting the barrow run, for a week’s use.
- Aerial ropeway. Cables and winches can be used to move stone across steep, rough slopes and gullies. Two Tirfor winches are needed, one to tension the cable, and the other to winch the stone. A ‘descendeur ’, as used in rock climbing, is needed at the upper end, to slow the descent. About four large stones can be moved at a time, in a ‘basket’ of chain-link fencing with two slings beneath. To avoid misuse, the ropeway must be taken down at the end of each working day, and the parts hidden under a boulder nearby. Ensure that the challenge of operating an aerial ropeway doesn’t divert volunteers from the main task of building the path!
Aerial ropeways should only be erected by experienced persons, who should likewise closely supervise their operation. Great care must be taken that there is no danger to the public, staff or volunteers. - Timber rollers. Large stones and slabs can be moved using fencing-stake sized posts as rollers.
- Airlift. Where there is insufficient stone in the locality, a helicopter airlift is the most efficient way of bringing stone onto the site.
Where there is potential danger to the public when stone is being moved, walkers should be kept off the path if possible, or asked to wait while stone is being moved. Extra precautions may be necessary if the section being worked is above a road or carpark. The National Trust Carneddau footpath team erected a temporary safety fence of chain link fencing on metal posts, to trap any falling stones, when working on a steep and exposed section of path directly above a main road.
The following sections describe methods of pitching as developed in different areas of the country.
Lake District
The following advice is based on pitching techniques used by the National Trust and The Conservation Volunteers.
Paths which need attention are walked and inspected carefully before any work begins, and the site is checked at least twice in wet weather to mark the positions where water flows onto the path. Sources of stone are checked.
Tools needed depend on personal preference, but the minimum is a pick, crowbar and shovel per two workers. Some pitchers like to have a walling hammer for knocking stone into position, or for splitting a big stone to give two good faces for pitching. A swan-neck crowbar is useful for levering stones into position, but is not as strong as a straight crowbar. A tarpaulin and yard brush may also be useful.
When work commences, the first job is to collect stones and put them ready along the line of the path. The length of time needed will vary with conditions, but two days spent collecting stone for a week-long volunteer project would be typical. Cut-off drains are then made, starting from the top of the path. If conditions are fairly dry, and the work is expected to be finished within a week or two, the drains are just cut with a mattock, and then lined with stone later as work progresses. If the job is going to take longer, the drains are properly constructed and the path above and below pitched, as described here.This will keep the path dry enough for working, and prevent further erosion occurring while work is in progress.
Pitching progresses in an upwards direction. A volunteer project will need to divide into teams, usually of two people each, with each team working on a section of path.
Experienced pitchers would normally work singly,teaming up to move very large stones. Where possible, divide the path at cut-off drains, large boulders or any other breaks in the path. Plan the work so that sections are joined by the end of the project.
Dig out the spoil for about a metre ahead, and pile it neatly to the side. It can be put on a tarpaulin for easy retrieval. As pitching progresses, some can be put straight onto the pitched section below, and then brushed into the gaps with a yard brush. Don’t dig further than about a metre ahead, in case bad weather or other circumstances intervene, which may mean the ground is left exposed to erosion.
Choose large stones for the bottom edge of the path or of each section worked, to provide a strong base course. Set the stones so that the tops are horizontal, with a maximum rise of four fingers (about 80mm), giving a stepped profile. If the stones are set flush with the slope of the ground, the resulting surface is very slippery for downhill use.
Jam each stone against the preceding one. If a stone is wedge-shaped, use the longest face on the downhill side.
Set the stones with their tops just below the surrounding ground level. This helps channel users onto the path, and disguises the path better when viewed from a distance. Ensure that each stone is soundly bedded so that it will not sink with use. Try to work in courses of similar-sized stone, laying the stone with the grain across the path. Stagger the courses as in walling. Vary the width to make the path look less obtrusive.
To avoid the formation of formal ‘steps’, vary the height of the stones across the width of the path as shown.
As each section is finished, fill gaps with spoil trodden or brushed in. As work progresses, use extra spoil to repair eroded gullies and path edges. If there is not sufficient spoil to fill a gully, build rough dams of stones across the gully at intervals to catch stones and silt washed down by rain. These also act as barriers to discourage walkers from taking short cuts. Any low stone barriers built to prevent erosion or to discourage walkers should be made as roughly as possible, so that they look ‘natural’. As vegetation recovers and grows over them, they will blend completely into the surroundings. A neatly constructed wall will remain noticeable. Where a stronger construction is needed to safely build a higher wall, build of alternate layers of stones and layers of sods, a style known as Cumberland banking. As the sods grow, the wall is hidden. For further details on vegetation restoration see Chapter 11 – Erosion control and vegetation restoration.
North Wales
The National Trust Carneddau footpath team use a similar basic technique to that described above, although greater use is made of wedging stones to fill the gaps between the larger stones. Two or more stones are usually needed to give sufficient area for each step. The average rise between steps is 100mm, up to a maximum of 200mm.
Pitched paths have also been successfully built on level and gently sloping ground, to restore heavily used paths such as those at Cwm Idwal. The path is excavated to 300-400mm depth, and the stones pitched with a cross-fall, giving a finished path surface about 150mm below the level of the surrounding turf. Sometimes the soil beneath the turf is dug away as shown, and the turf reprofiled to meet the edge of the path. In other places, large stones are placed underneath the overhanging turf to support it, and to discourage people from walking off the path.
Where crossing steeper ground, large stones may be needed on the lower side to form a retaining wall. For further details on revetments, see Chapter 11 – Erosion control and vegetation restoration.
Overlapping side stones are sometimes used to direct the water flow down the path, rather than it going down an unstable slope which would rapidly undermine the pitching. The water is then taken off the path at a suitable point by a cut-off drain.
The Cleveland Way Project
The Cleveland Way Project in the North York Moors National Park produce detailed specifications for stone pitched and other types of paths, which are used for specifying work to be done by contractors. The following details are taken from the specifications (Cleveland Way Project, unpublished notes).
The general specification for a pitched path is that it should be of a natural looking variable width from 1.3 to 1.5m, with a crossfall of between 2 and 5 degrees, shedding water to the downhill side. Paths are routed as close as possible to the existing alignment, taking a natural line with an even gradient, and keeping straight lengths to a minimum.
Stone excavated during the work is used if possible to construct the path, and extra stone bedded in alongside to provide natural barriers to discourage walkers from leaving the path. All vegetation excavated during construction is carefully handled and bedded in on eroded areas. Gaps between the pitched stones are packed with small stones, well compacted, to provide a firm, stable construction which will not loosen, and will not allow water into and under the construction. Excavated soil is mixed with fertilizer and seed and used to infill gaps in the path construction, and on adjacent eroded areas.
The stone used for pitching is reclaimed variable sized local walling sandstone, which is airlifted to site in heavy duty bags, each containing between 900kg and 1000kg of stone. The bags are placed at regular intervals along the path line, and retained by temporary barriers on slopes. The ratio of length of path (average width 1.4m) constructed per bag of stone depends on the type and size of stone being used. For sandstone, a length of 1.6m is average per 1000kg of stone. When using denser gritstone, a length of 1.4m is average. This adds up to a large volume of stone being airlifted, but with efficient organisation and very short turn-around times for each load, often less than two minutes, this has been proved to be a cost-effective method of transporting stone.
The basic technique for pitching is similar to that described above, with the stones set in on their long axis, with the upper surface of rough, natural appearance, and positioned to provide a walking surface of irregular angled shallow rise steps. To give sufficient foothold, the surface of each step must be a minimum of 250mm along the line of the path, made of one large stone, or two or more adjoining stones set level.
The angle of the walking surface should be approximately halfway between horizontal and the existing ground slope. The steps should have a maximum rise of 50mm on average gradients, up to a maximum of 100mm on steeper gradients.
Avoid rows of stones which give a formal step appearance, and avoid four way joins, which are unstable. Keep the edges uneven and natural looking. Cut-off drains are constructed at intervals of between 5m and 10m, depending on the nature of the ground.
Where the path cuts across and into the slope to obtain an easier gradient, stone revetments are constructed to stabilise the slope above and below the path. Where possible, use is made of large, stable in-situ rocks, with the path taken around and above them.
The Cleveland Way Project has also developed successful methods of using pitching stone with stone slabs on gently sloping paths.
Scotland
In Scotland, Pathcraft Ltd. have pitched several paths up slopes which had become highly eroded, in order to stabilise the slopes. The Coire nam Beith path in Glencoe includes some very steep sections where the path zigzags up slopes of over 30 degrees. Pitching was done over a period of years, until a length of about 1km was completed. Reseeding and other stabilisation work was done, to give very good recovery of the previously eroded slopes. All the pitching stone was gathered nearby from the hillside and burn. The path is mostly under 600mm wide, which is appropriate for the use it receives, mainly from rock climbers, and is virtually impossible to detect from a distance as an ‘improved’ path. Particular care is taken that the pitching is never exposed above the level of the surrounding ground.
In contrast, the first steep section of the path in Glen Nevis leading from the youth hostel bridge up towards Ben Nevis was pitched using stone flown in by helicopter. Due to the very high numbers of tourists using this path, it was constructed to a width of about 1.5m. Some sections, especially at corners, had to be built up considerably in order to gain sufficient height where the route was constrained by a boundary. A length of about 600m was completed over three winters, and now provides a durable path, appropriate for the use it receives, which will contain trampling and allow recovery of the hillside.
Pathcraft Ltd. have teams of five people, and for pitching tend to work in two pairs on two ‘fronts’, with the fifth person helping where needed. In each pair, one collects stone and one places them, swapping over at intervals. Cross drains are built in preference to cut-offs, as these are found to be more effective.
Beacon Fell Country Park, Lancashire
Beacon Fell is acidic grassland and heath with conifer plantations, rising to 266m above sea level. It is a very popular viewpoint, and trampling had destroyed the turf on paths, exposing the peat and underlying gritstone. A variety of types of pitching have been done.
Setts are stones especially worked as a surfacing material. They may give an ‘urban’ look to the path, but are easier to lay and make a smoother surface than unworked stone. Second-hand setts from old pavements and roads may be available. Lay the setts on a 75mm sub-base of sand well tamped down, with more sand tamped in as filling between the setts. It is not worth trying to construct an ‘informal’ edge, as it is then difficult to hold the setts in place. In the method below, used at Beacon Fell, the stone edging forms part of the side drain.
The local walling stone is a rather angular and block- shaped gritstone, heavy enough to be laid with the long axis forming the walking surface. This is only possible with stones of the dimensions shown below, and anything smaller must be laid with the long axis vertical.
