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Inspection of Walling Work

PREAMBLE

This is one of a series of leaflets designed to give guidance on particular aspects of dry stone walling. The series as a whole will help professional decision makers such as local authorities, architects, landscape designers, land agents, etc., to judge the merits of different tenders, to draw up specifications for dry stone work and to assess the quality of the work that is being or has been done.

This leaflet gives guidance on what to look for in dry stone walls so you have value for money and know that they have been built to last. It has been produced in response to requests to the DSWA over the years concerning the quality of work that has already been carried out.

Before detailing guidelines for the inspection of work, it is important to appreciate that even a good craftsman needs to be supplied with suitable conditions in order to produce a good job. The final result is the product of the craftsman, the stone and the land.

  1. There is an enormous difference between the best and the worst workmanship, a qualitative gap probably greater than for any other skill. It is therefore essential to employ a qualified professional and the DSWA will supply its register of professional members on request. The DSWA operates a scheme of skill certification involving careful testing. The level of qualification attained by each member is indicated in the register.
  1. The earth or rock sub-foundation on which the stone wall is to be built needs to be level, firm and at a depth specified by the waIler, unless he is to undertake this himself as part of the contract. 3. It is necessary to have clean material, uncontaminated by soil or anything else, delivered to hand at the rate required.
  1. It is essential, if a specific “style” is required, for stone to be provided that enables faithful execution of the specification. The stone must be sound, long Iasting, of suitable size andrange of sizes with sufficient foundation stones, through stones, fillings and top stones.
  2. No mortar should be used unless specified for special reasons.
This piece of Double is insecure.

GUIDELINES FOR THE INSPECTION OF DRY STONE WORK

  1. The wall should be inspected during the construction as well as after completion.
  1. The size of the wall should meet the minimum dimensions given in the specifications and should conform to the specified style. A leaflet “Technical Specifications for Dry Stone Walls” describes the specification and is available from DSWA. The foundations (the initial course upon which the subsequent structure is built) should consist of large, flat stones that should each reach at least a third of the way across the wall. In some areas the foundations project 2-4″ beyond the base of each face of the wall. If an inspection is carried out during construction, which is recommended, foundation stones should not move appreciably when walked on.
  1. Stand a few metres away and look directly at each face. There should be no “running joints’; that is the stones should be bonded as with brickwork with a stone across each joint in the course below. However, in some stonework, two small face stones are often laid upon each other to level up to an adjacent larger stone, causing an apparent short running joint that is permissible. Stones should be graded with the larger at the bottom except where the local style differs.
  1. All stones should be placed to touch all their neighbouring stones so that there is no room for movement. There should be little or no front pinning, which is the procedure of wedging the building stones on the outer face using small stones pushed in from the front. This, unfortunately, is frequently done in an attempt to disguise poor workmanship when the stones are not laid tightly enough. It should not be possible to move any stone by hand.
  2. The fillings, or internal packing of small stones should be firm with no spaces for settling or movement of the face stones inwards. The fillings are best inspected during the construction since it is impossible to examine the internalstructure after completion. However, a check can be made on the thoroughness or otherwise of the packing by a sharp blow to the face. The force used should not be severe; there should be little or no inward movement.
  3. Examine the throughstones. If at all possible they should be cut to project not more than2-3″ beyond the face of the wall, particularly if stock have access. Any sharp edges should have been blunted. Look beneath the throughstone to check that the top surface of the supporting stones are secure against bottom surface of the throughstone. There should be at least the specified number of throughstones.
  1. Kneel down and look along the face of the wall. It should be absolutely straight and true along its length without waviness, bulges or overhangs. Look down the wall from the top; the batter (the angle of taper to the vertical) should be even from top to bottom.
  1. The coverstones are flat stones similar to throughstones that cross the width of the wall at the top, immediately below the copestones (these are not used in all regional styles).
  1. The upper line of the top stones or copestones should be completely level, unless there is a regional variation to this. If laid in vertical style, all should be vertical. If laid at an angle, all copestones should be laid at the same angle. Give the copes a firm, sideways push – they should be completely rigid. The copestones like coverstones, should cross the width of the wall and touch the tops of the stones in faces of both sides. The copestones should not project beyond the faces of the wall. The pinning – small stones wedged in the gaps between the copesshould be pushed in flush to the main structure.
  1. General: the top of the wall should not have sharp peaks and troughs when following undulating ground, but gently follow the contours. On gentle slopes, the courses should be parallel with the ground; on sharper gradients the courses should be laid horizontally, and stepped. Stand back and look at the finished product. There should be distinct lines: foundations, throughstones, coverbands (where used) and top/copestones.

DISPUTES

In the case of disputes involving dry stone work, the Association has a list of recommended assessors who can undertake inspection. Details of the service are available from DSWA, without obligation.

FURTHER INFORMATION
The Association endeavours to respond to all requests for specific information regarding dry stone wailing. The DSWA offers a mail order service on books, which includes a number of technical manuals, which would make useful reading, and produces a register of working wallers, which is free of charge. Full details available on request (please include a stamped, self-addressed envelope).

Dry Stone Walling Association
Westmorland County Showground,
Lane Farm, Crooklands,
Milnthorpe, Cumbria, LA7 7NH

tel: 015395 67953
www.dswa.org.uk