Slate: Another practice settlers brought to the New World was
slate roofing. Evidence of roofing slates have been found also
among the ruins of mid-17th century Jamestown. But because of the
cost and the time required to obtain the material, which was mostly
imported from Wales, the use of slate was initially limited. Even
in Philadelphia (the second largest city in the English-speaking
world at the time of the Revolution) slates were so rare that
"The Slate Roof House" distinctly referred to William
Penn's home built late in the 1600s. Sources of native slate were
known to exist along the eastern seaboard from Maine to Virginia,
but difficulties in inland transportation limited its availability
to the cities, and contributed to its expense. Welsh slate continued
to be imported until the development of canals and railroads in
the mid-19th century made American slate more accessible and economical.
Slate was popular for its durability, fireproof qualities, and
aesthetic potential. Because slate was available in different
colors (red, green, purple, and blue-gray), it was an effective
material for decorative patterns on many 19th century roofs (Gothic
and Mansard styles). Slate continued to be used well into the
20th century, notably on many Tudor revival style buildings of
the 1920s.
 Replacement of particular historic details is important to the individual historic character of a roof, such as this rounded butt wood shingle roof. In the restoration, the drainage around a dormer was improved by the addition of carefully concealed modern metal flashing. Photo: NPS files. |
Shingles: Wood shingles were popular throughout the country in
all periods of building history. The size and shape of the shingles
as well as the detailing of the shingle roof differed according
to regional craft practices. People within particular regions
developed preferences for the local species of wood that most
suited their purposes. In New England and the Delaware Valley,
white pine was frequently used: in the South, cypress and oak;
in the far west, red cedar or redwood. Sometimes a protective
coating was applied to increase the durability of the shingle
such as a mixture of brick dust and fish oil, or a paint made
of red iron oxide and linseed oil.
Commonly in urban areas, wooden roofs were replaced with more
fire resistant materials, but in rural areas this was not a major
concern. On many Victorian country houses, the practice of wood
shingling survived the technological advances of metal roofing
in the 19th century, and near the turn of the century enjoyed
a full revival in its namesake, the Shingle Style. Colonial revival
and the Bungalow styles in the 20th century assured wood shingles
a place as one of the most fashionable, domestic roofing materials.
 Galvanized sheet-metal shingles imitating the appearance of pantiles remained popular from the second half of the 19th century into the 20th century. Photo: NPS files. |
Metal: Metal roofing in America is principally a 19th-century
phenomenon. Before then the only metals commonly used were lead
and copper. For example, a lead roof covered "Rosewell,"
one of the grandest mansions in 18th century Virginia. But more
often, lead was used for protective flashing. Lead, as well as
copper, covered roof surfaces where wood, tile, or slate shingles
were inappropriate because of the roof's pitch or shape.
Copper with standing seams covered some of the more notable early
American roofs including that of Christ Church (1727-1744) in Philadelphia.
Flat-seamed copper was used on many domes and cupolas. The copper
sheets were imported from England until the end of the 18th century
when facilities for rolling sheet metal were developed in America.
Sheet iron was first known to have been manufactured here by the
Revolutionary War financier, Robert Morris, who had a rolling
mill near Trenton, New Jersey. At his mill Morris produced the
roof of his own Philadelphia mansion, which he started in 1794.
The architect Benjamin H. Latrobe used sheet iron to replace the
roof on Princeton's "Nassau Hall," which had been gutted
by fire in 1802.
"Roofing" an Historic Preservation Brief
