![]() Most of these older cement repairs are now cracking and require to be replaced. 'Plastic Repairs' using cement mortar was often used to repair stones. Whinstone used with red sandstone detailing John Gilbert Problems Past repairs It is hard to shape so is not normally used for detail. Whinstone is the term used to describe a range of dark coloured hard, dense rocks such as basalt and dolerite. Granite stone Commonly used in the north-east of Scotland in and around Aberdeen Whinstone While this is an overall advantage, it does mean that rain will penetrate cracks and run directly into the building rather than being absorbed by the stone. It does not weather as easily as sandstone and is less porous so does not absorb water as easily. ![]() Granite is a durable, hard stone that is pale or silvery grey though a pink granite was also used around Peterhead. Grey Sandstone John Gilbert A buff grey sandstone was commonly used in Edinburgh, sourced from the Craigleith Quarry. (Cleaned sandstone on left) Red and blonde sandstone Annie Flint With the advent of railways, red sandstone started to succeed blonde sandstone as a building material. Blonde Sandstone Annie Flint Commonly found in tenements in the west of Scotland, the cream coloured stones darken with air pollution. The stone needs to be laid with the correct alignment of the bedding (generally a horizontal bedding). Sandstone has a distinct "bedding" or alignment caused by the way the stone was formed in layers. ![]() It is relatively easy to carve and shape. It is also porous so it absorbs water easily and needs to be kept dry if possible and allowed to dry if it gets wet. Sandstone is the softest of building stones used in tenements. Timbers set into these thinner walls are most vulnerable to decay from damp and rot. The walls at bays, oriels and corner turret windows are thinner than the main external walls and less able to hold moisture. The internal finished plaster surfaces are fixed to the stone wall but have an air gap which allows water vapour to travel through the wall. Lime mortar bonds the materials together. ![]() ![]() External stone walls are usually about 600mm thick, made from a stone outer face and rougher infill stone or brick inside. ![]()
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