thumb|[[Dry stone|Dry ashlar masonry laid in parallel courses on an Inca wall at Machu Picchu]]
thumb|Ashlar masonry north gable of [[Banbury Town Hall, Oxfordshire]]
thumb|[[quarry-faced stone|Quarry-faced red Longmeadow sandstone in random ashlar was specified by architect Henry Hobson Richardson for the North Congregational Church (Springfield, Massachusetts, 1871).]]
Ashlar () is cut and dressed stone worked to achieve a specific form, typically rectangular; a structure built from such stones; and the look created by the dressing technique. Ashlar stone may be dry laid or bedded in mortar.
Description
An ashlar block is the finest stone masonry unit, and is generally rectangular. It was described by Vitruvius as opus isodomum, or trapezoidal. Precisely cut "on all faces adjacent to those of other stones", ashlar masonry is capable of requiring only very thin joints between blocks, and the exposed face of the stone may be smoothly polished, quarry-faced, rusticated, or tooled for decorative effect; "Clene hewen ashler" often occurs in medieval documents; this means tooled or finely worked, in contradistinction to rough-axed faces.
In tile carpet installation "ashlar" refers to a vertical 1/2 offset pattern.
Use
Ashlar blocks have been used in the construction of many buildings as an alternative to brick or other materials.
In classical architecture, ashlar wall surfaces were often contrasted with rustication, each employing different chisels and techniques.
The term is frequently used to describe the dressed stone work of prehistoric Greece and Crete, although the dressed blocks are usually much larger than modern ashlar. For example, the tholos tombs of Bronze Age Mycenae use ashlar masonry in the construction of the so-called "beehive" dome. This dome consists of finely cut ashlar blocks that decrease in size and terminate in a central capstone.
See also
- Ablaq
- Dimension stone
- Opus quadratum
- Stone veneer
References
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