Rocks

Rock structures have existed for as long as history can recall. It is the longest lasting building material, and is usually readily available. There are many types of rock throughout the world all with differing attributes that make them better or worse for particular uses.

Rock is a very dense material so it gives a lot of protection, its main draw-back as a material is its weight and awkwardness. Rock walls have very good thermal mass, which means that they absorb the outside temperature, hold it in and then radiate it through the home. Thermal mass is best used in desert climates because of the difference in day and night temperatures, and the release of heat is cyclical. During a hot day, walls with thermal mass will absorb and store the sun's heat while the inside of the house remains cool. At night, when outside temperatures drop, the daytime heat stored in the walls radiates inward to warm the home. Thermal mass can be energy efficient since the house heats and cools itself, instead of relying on a furnace or air conditioner.

It's much easier to build with perfectly shaped bricks or slabs of concrete, but it's possible to build beautiful homes with locally available rocks. Dry-stone walls have been built for as long as humans have put one stone on top of another. The rocks can be mortared with earthen plasters such as sand and clay or lime. Eventually different forms of mortar were used to hold the stones together, cement being the most commonplace now. Mortared stone structures are less durable than dry stone, because water can get trapped between the stones and push them apart.

Traditional stone masonry is rarely used today, because stone is 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.

Slipform stone structures are a cross between veneered masonry and traditional masonry. Short forms (around 2 feet tall) are placed on either side of the wall, to serve 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 quickly and easily with this method.

Circular huts were constructed from loose granite rocks throughout the Neolithic and early Bronze Age, and the remains of an estimated 5,000 can still be seen today. The pyramids in Giza, burial chambers in the UK and temples in Malta were all built from stone over 4000 years ago and are still standing. Granite continued to be used throughout the medieval period and into modern times. Slate is another stone type, commonly used as roofing material where it is found.

Rocks are extremely durable, artistic, versatile building material with high thermal mass, can be used for walls, floor, roof, arches; blends with natural landscape, can be easily recycled.... BUT... very labor-intensive and expensive now a days. To meet sustainability standards, steps must be taken to ensure that the stone is found on site, reclaimed from nearby demolished buildings or sourced from a local stone quarry. Only then can stone be considered a true example of a sustainable building material.

- compiled by blogger.