Flagstone (flag) is a generic flat
stone, sometimes cut in regular rectangular or square shape and usually used for
paving slabs or walkways, patios, flooring, fences and roofing. It may be used for memorials,
headstone
A headstone, tombstone, or gravestone is a stele or marker, usually stone, that is placed over a grave. It is traditional for burials in the Christian, Jewish, and Muslim religions, among others. In most cases, it has the deceased's name, da ...
s,
facades and other construction. The name derives from
Middle English ''flagge'' meaning turf, perhaps from
Old Norse ''flaga'' meaning slab or chip.
Flagstone is a
sedimentary rock that is split into layers along
bedding planes
In geology, a bed is a layer of sediment, sedimentary rock, or pyroclastic material "bounded above and below by more or less well-defined bedding surfaces".Neuendorf, K.K.E., J.P. Mehl, Jr., and J.A. Jackson, eds., 2005. ''Glossary of Geology'' ...
. Flagstone is usually a form of a
sandstone composed of
feldspar and
quartz and is
arenaceous in grain size (0.16 mm – 2 mm in diameter). The material that binds flagstone is usually composed of
silica,
calcite
Calcite is a Carbonate minerals, carbonate mineral and the most stable Polymorphism (materials science), polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on ...
, or
iron oxide
Iron oxides are chemical compounds composed of iron and oxygen. Several iron oxides are recognized. All are black magnetic solids. Often they are non-stoichiometric. Oxyhydroxides are a related class of compounds, perhaps the best known of whic ...
. The rock color usually comes from these cementing materials. Typical flagstone colors are red, blue, and
buff, though exotic colors exist.
Flagstone is
quarried
A quarry is a type of open-pit mining, open-pit mine in which dimension stone, rock (geology), rock, construction aggregate, riprap, sand, gravel, or slate is excavated from the ground. The operation of quarries is regulated in some juri ...
in places with bedded sedimentary rocks with
fissile bedding planes.
Around the thirteenth century, the ceilings, walls and floors in European architecture became more ornate. Anglo-Saxons in particular used flagstones as flooring materials in the interior rooms of
castle
A castle is a type of fortified structure built during the Middle Ages predominantly by the nobility or royalty and by military orders. Scholars debate the scope of the word ''castle'', but usually consider it to be the private fortified r ...
s and other structures.
[Williams, Henry Smith (1910). ]
A history of science, Volume 9
', p. 154. Harper Brothers, New York and London. Lindisfarne Castle in
England and
Muchalls Castle (14th century) in
Scotland are among many examples of buildings with surviving flagstone floors.
Flagstone shingles are a traditional roofing material, and are a type of
roof shingle commonly used in the
Alps, where they are laid dry – often held in place with pegs or hooks. In the
Aosta Valley, Italy, buildings in historical areas are required to be covered in stone shingles.
See also
*
Slate in buildings
*
Stone wall
*
Step-stone bridge
*
Patio
*
Pavement
References
{{Stonemasonry
Building stone
Pavements
Types of wall
Garden features
Sandstone
Stone (material)