Introduction
The Secretary of the Interior's "Standards for Rehabilitation"
call for the repair or replacement of missing architectural features
"based on accurate duplication of features, substantiated
by historic, physical, or pictorial evidence rather than on conjectural
designs." On a wooden shingle roof, it is important not only
to match the size, shape, texture, and configuration of historic
shingles, but also to match the craftsmanship and details that
characterize the historic roof. Proper installation and maintenance
will extend the life of the new roof.
Wooden shingle roofs are important elements of many historic buildings.
The special visual qualities imparted by both the historic shingles
and the installation patterns should be preserved when a wooden
shingle roof is replaced. This requires an understanding of the
size, shape, and detailing of the historic shingle and the method
of fabrication and installation. These combined to create roofs
expressive of particular architectural styles, which were often
influenced by regional craft practices. The use of wooden shingles
from the early settlement days to the present illustrates an extraordinary
range of styles.
Readily available and inexpensive sawn shingles were used not only for roofs, but for gables and wall surfaces. Photo: Lane County Historical Society.
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Wooden shingle roofs need periodic replacement. They can last
from 15 to over 60 years, but the shingles should be replaced
before there is deterioration of other wooden components of the
building. Appropriate replacement shingles are available, but
careful research, design, specifications, and the selection of
a skilled roofer are necessary to assure a job that will both
preserve the appearance of the historic building and extend the
useful life of the replacement roof.
Unfortunately, the wrong shingles are often selected or are installed
in a manner incompatible with the appearance of the historic roof.
There are a number of reasons why the wrong shingles are selected
for replacement roofs. They include the failure to identify the
appearance of the original shingles; unfamiliarity with available
products; an inadequate budget, or a confusion in terminology.
In any discussion about historic roofing materials and practices,
it is important to understand the historic definitions of terms
like "shingles," as well as the modern definitions or
use of those terms by craftsmen and the industry. Historically,
from the first buildings in America, these wooden roofing products
were called shingles, regardless of whether they were the earliest
handsplit or the later machine-sawn type. The term shake is a relatively
recent one and today is used by the industry to distinguish the
sawn products from the split products, but through most of our
building history there has been no such distinction.
Considering the confusion among architects and others regarding
these terms as they relate to the appearance of early roofs, it
should be stated that there is a considerable body of documentary
information about historic roofing practices and materials in
this country, and that many actual specimens of historic shingles
from various periods and places have been collected and preserved
so that their historic appearances are well established. Essentially,
the rustic looking shake that we see used so much today has little
in common with the shingles that were used on most of our early
buildings in America.
Throughout this Brief, the term shingle will be used to refer
to historic wooden roofs in general, whether split or sawn, and
the term shake will be used only when it refers to a commercially
available product. The variety and complexity of terminology used
for currently available products will be seen in the accompanying
chart entitled "Shingles and Shakes."
This Brief discusses what to look for in historic wooden shingle
roofs and when to replace them. It discusses ways to select or
modify modern products to duplicate the appearance of a historic
roof, offers guidance on proper installation, and provides information
on coatings and maintenance procedures to help preserve the new
roof.(1)