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Build a Retaining Wall. A retaining wall is a functional wall, put in where there is a sharp drop in the ground level, in order to prevent the soil from the ground above being washed down to the lower level. Although it is functional, it can also be a thing of great beauty, particularly if it is built from local stone without any mortar. These dry-stone (meaning unmortared) walls or dykes can last for a hundred years or more if they are properly made. If they are regularly maintained by replacing any fallen stones, they should last for ever. There are many reasons that you might wish to build a retaining wall from dry stone, but the main reason, apart from its aesthetic qualities, is its ability to deal with wet conditions. Any retaining wall will need to be able to cope with considerable moisture coming from the soil behind it. Moisture can penetrate mortar in a retaining wall. In freezing conditions the mortar will then crack and the wall will be de-stabilised. In a dry-stone wall, the water seeps through the small gaps between the stones without causing damage. It is easier to build a retaining wall than a free standing wall because you have only one 'face', the front of the wall that is visible and needs to be straight and level. The wall will still consist of two walls of stone which start a yard apart at the foundations. As you build upwards, these two walls slope inwards towards each other until they meet at the top of the wall. The space between them is tightly filled with smaller stones. For the rear wall, you can use stones that do not have a good enough shape to be used on the front side. 
Start by excavating the ground for the base until you reach a hard subsoil. On this subsoil, lay your opposing walls of foundation stones. These should be large heavy stones. Fill any gaps between the two rows of foundation stones with small stones. Lay the next course of stones on top, filling the middle well and checking that the front face is relatively smooth and level. Periodically put in a 'through stone', a long stone that will stretch from the front of the wall to the back and lock the wall together. Continue to lay the courses of stone, starting with larger stones on the lower courses and smaller stones as you approach the top. Keep the middle tightly filled. As you complete each course, rake down the soil from behind the wall so that it is firmly packed against the back of the wall. Tamp the soil down well; to build a retaining wall that will last, you do not want to leave any airholes behind it. When the front and back walls have met at the top, you must now put on the cope stones. These are heavy stones which span the top of the wall from side to side, overlapping it slightly. Their weight stabilises the wall from above. The cope stones can be stones of irregular shape. In fact, the copes can be used to excellent sculptural effect if they stand on their sides and give a broken line along the top. You will be amazed at how much stone is required to build a retaining wall with this method. You may also be amazed to find that you have become addicted to dry-stone dyking - many people do! |
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