Building Materials

Evolution of Stone Construction Form

Dry Stone Stacking

Dry stone stacking the earliest form of stone construction. These are free standing structures such as long distance field walls and bridges. Stones with irregular shapes are carefully selected and placed so that they hold each others closely and tightly together without slipping.  Furthermore, as height increases structures which possess wider base are needed. Plus, the support of structure is originated from the weight of the stone which tends to push inwards, and  settling makes the structure lock tightly together and become more stable and stronger. Dry stone structures have high durability. Moreover, dry stone structures do not need frequent maintenance as they allow water to drain through them, without causing damage to the stones. In addition, this form of stone construction do not require any special equipments, only the skill and technique of the craftsman in selecting and placing the stones.

Stone Masonry

Traditional stone masonry is the evolution form of stone construction of dry stone stacking. Stone blocks are placed in rows evenly (courses) or unevenly (uncoursed) height, and hold together tightly with the addition of mortar, a cement or lime mixture between the stones. The building stones are conventionally extracted by surface quarrying, drilled and split using diamond saws or iron wedges, and then shaped and polished according to their requirements. The basic hand equipments used to shape stones are chisels, mallet and a metal straight edge, but modern power tools such as angle grinders and compressed air-chisels are often used to save time and money. Plus, stones are either shaped into a block, known as ashlar masonry, or left rough and cut irregularly, known as rubble masonry. However, mortared stone structures have lower durability than dry stone         structures, because water can easily get trapped between the stones and push them apart.

Stone Cladding

Nowadays, traditional stone masonry is rarely used because stone is rather expensive to quarry, cut and transport, and the building process is labour and skill-intensive. Instead, most modern stonework utilises a veneer of stone (thin, flat pieces) glued against a wall of concrete blocks. This is known as veneered stone or stone cladding.

Slip Form Stone Structure

Slip form stone structures are a combination between veneered masonry and traditional masonry. Short forms (around 2 feet tall) are placed on either side of the wall, to act as a guide for the structure. Stones are placed inside the forms with the flat face out, and concrete is then poured behind the rocks to hold it together. Stone buildings can be constructed swiftly and easily with this method.

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