Devon field boundaries: restoration standards for agri-environment schemes (TIN039)

Dry stone walling

Dry stone walling should be undertaken in accordance with the best standards, traditions and designs of your district. The style should always be consistent with other walls in the immediate locality This may include undressed or single skin constructions or the absence of through stones. In some areas mortared walls may be locally traditional. Where these are to be restored a suitable lime mortar mix should be used, which is breathable and will not crack like ordinary cement.

Figure 7 Newly restored stone faced bank

Where existing walls are being renovated the old wall should be taken down to its foundations before starting work. Where the original stone is no longer available, eg it has been removed in the past or is not in a viable condition to be re-used, replacement stone must be sourced locally and be of a type used in the area. Stone must not be taken from other walls, hedge banks or buildings. Old features of the wall, such as creep holes or built in granite troughs, should be restored and retained.

Please note:
  • Haul stone only when ground conditions are firm enough to prevent damage to adjacent fields.
  • A supplementary payment is available where stone needs to be brought in.
  • The site should be left level and tidy, with surplus stone removed from the site, any earth pits filled in and any disturbed areas returned to grass.
  • Building or restoring a dry stone wall is skilled work. If you do not have the necessary skills to complete the work to the required standard, then we recommend that you employ a reputable contractor.

Figure 8 Example of a dry stone wall

Building a double skinned wall

The foundations or footings should consist of two rows of the largest, evenly shaped stones available, set into a trench of firm subsoil, and should be about 75mm (3'') wider than the base of the wall. Place stones with their longest dimension running into the centre of the wall, with rubble stone packed firmly around them. Soil and other fine stone should not be used as infill because it will wash out.

Figure 9 Example of a dry stone wall

Build up the stones layer by layer, always maintaining the infill slightly higher than the face as you go. Each stone should be firmly seaton the course below, incorporating long tie stones at staggered intervals.

The joints must be broken as in building brickwork and the stones should be set level, or preferably with a slight outward slope to assist drainage. There must be at least one row of through stones at least the width of the wall, seated firm;y to create a strong tie.

Figure 10 Corss section and top view of double skinned wall

Figure 11 Square form of wall ending

There should be two even faces that follow the batter with no bulbes or protruding stones other than the through stones. The wall should taper evenly on both sides to the top.

Coping stones on the top should sit on a level finish and should either be large flat slabs in upright or sloping position or built in castellated style. These stones must be the full width of the wall and sit firmly on both sides to hold the wall secure.

There are two types of wall ending; the square form, which has tie stones across the end, and a quoin, which has a rounded end.

Figure 12 Round form of wall ending
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