Stone
Detail of Greenstone entrance showing mixture of stone types.
Granite column, limestone carved doorway, rough "rusticated" limestone
blocks,
green Cincinnati stone in walls.
Photo: Dan Spector
One of the earliest construction materials used is stone.
It was obtained in two ways: from natural outcroppings or scattered deposits,
and by the process of quarrying. Many early buildings were constructed
of stone readily available near the building site. Along river valleys,
limestone was prevalent. This stone was removed in natural layers, or strata,
by the simple technology of picks and crowbars. Early stonemasons were
familiar with the properties of limestone and other sedimentary stone,
and exercised care to 'lay up,' or set, the stone in accordance with its
'bedding plane,' i.e. its natural geological layering. If the bedding plane
ran horizontally in the deposit, the stone was laid so that this bedding
plane was also horizontal in the construction of the wall. When sedimentary
stone is not laid up in accordance with its bedding plane and the stone
is laid vertically, problems can arise. This improper practice has been
used by contractors when the original thickness of the stone is not readily
available and they are required to lay up the stone as a 'veneer' or facing.
When the stone is not in its bedding plane, it is at its weakest, it will
absorb moisture between strata, and it will 'spall' --fracture-- and lose
its surface as a result of thermal stress and weathering. Early stonemasons
were also aware that certain stone types had more 'weatherability' and
were able to withstand the effects of weather better than others. As such,
they utilized each type in accordance with its particular properties. For
example, local Tennessee limestone has layers of clays and other impurities
throughout its strata and this can lead to erosion of the weaker materials
or spalling, depending on how the stone is set in the wall. Two restoration
projects at the Tennessee State Capitol building involved the replacement
of a significant amount of stone due to this problem, and ostensibly the
old Cossitt Library was demolished due to the spalling of its sandstone
walls. Locally the exterior of the Shelby County Courthouse is clad
with limestone. A colorful variation can be found in the Greenstone Apartments on Poplar. Another readily
obtainable type of stone is fieldstone, found in many areas of the country
affected by glaciers. In laying up fieldstone, adherence to bedding plane
is far less critical. Stones may be laid up in their natural form,
or broken and 'squared,' or shaped, for proper fit with other stone in the
wall. After milled lumber became available, fieldstone was used primarily
in foundations, fireplaces and chimneys.
Quarrying, the industrial practice of extracting stone from the
earth, requires substantial effort and technology. In this process, stone
is drilled, blasted, fractured or cut from the quarry face, and then shaped
and finished for use in construction. Tennessee limestone and sandstones
(such as crab orchard stone) have been quarried in this manner. Much of
the fieldstone used in Memphis was quarried in Arkansas. Fieldstone
was popularly used as a trim material or veneer during the era of Craftsman
houses beginning in the 1920s. Neighborhoods such as Vollintine-Evergreen,
Parkway Place and Shadowlawn all have fine examples of this stone. It is
one of the hallmarks of the late Depression era and pre-World War II Tudoresque
homes located in Mallory Heights East, Prospect Park in south Memphis,
Shirley Park in north Memphis and scattered sites throughout most of the
neighborhoods located inside the Parkways.