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ABOVE-GROUND ARCHAEOLOGY OF DEMOLISHED BUILDINGS
Donald Friedman1
Keywords
Building archaeology, recording, conservation, reuse
Abstract
Building archaeology, the study of buildings as physical artifacts to reveal their history, is
most typically used by people studying extant buildings or standing ruins; the study of buried
and abandoned foundations is closer to traditional archaeology. However, there is another possi-
bility in construction history: we can study extant above-ground traces of buildings that have
been demolished when those traces are preserved by neighboring structures.
There are several mechanisms by which a building can leave above-ground traces after its de-
molition. The most obvious is the presence of party walls, bearing walls that are shared by two
adjoining buildings. The demolition of one building cannot include the demolition of the party
wall, as that would destabilize the second building, and face of the wall exposed by demolition is
changed from interior to exterior. Details of the interior structure of the demolished building are
visible as remnants or scars on the exposed face: the location and geometry of stairs, partitions,
floor and roof joists, and fireplaces and flues may all become visible. A new building may be
built that incorporates an old wall, and may show these remnants on both the inside and outside
wall faces. New buildings may be constructed with accommodations for adjacent older struc-
tures, such as chimney extensions or geometry that wraps around old projections. New buildings
may hide remnants of windows and doors of demolished structures, or the removal of buildings
may allow new windows to be opened in previously inaccessible locations on neighboring struc-
tures.
Physical history is often studied within single buildings that have complex construction histo-
ries, such as medieval cathedrals, or in efforts to virtually reconstruct ancient monuments, but
can be of use in studying ordinary buildings in city centers. Adjacent buildings with different
owners are in many cases treated as independent structures, even when the presence of party
walls is known, and the demolition and construction of replacement buildings often proceeds
without designers and contractors considering the complications of site reuse.
This paper will review the types of traces that can be found on neighboring, unrelated struc-
tures. Examples of the various types will be illustrated with examples from the author’s practice,
showing how visible traces of the now-demolished buildings provide both a better understanding
of the past and information for future construction.
1 Old Structures Engineering, PC, 111 Broadway, New York, NY 10006 USA, dfriedman@oldstructures.com
5th International Congress on Construction History
Above-Ground Archaeology of Demolished Buildings
INTRODUCTION
Archaeological techniques have been extended to above-ground structures in the study of ru-
ins and buildings from antiquity through the late pre-industrial era. (Boato and Pittaluga, 2000)
This group of techniques, including analysis through dating building materials and examination
of alteration sequencing, can be simplified to a single technique for interpreting remnants of any
type of building, including poorly-documented “background” or vernacular buildings, provided
that the building type is understood. The purpose of such an analysis is to understand the history
of a site in order to make sense of a confused and confusing current physical configuration. An
extant building, even one of relatively recent construction as shown in the case studies below,
may be a collection of elements constructed at different timers for different purposes whose his-
tory is hidden by interior architectural finishes and exterior enclosure walls.
We can only accurately analyze remnants – usually fragments of exterior walls – in a specific
context, since the same physical evidence may have different meanings in different locations and
for different eras of construction. This is a tool, therefore, to be used by someone who knows the
historic context of the site. In other words, we can only interpret remnants with any accuracy
when we know the history of building types and development history of the location in question.
The use of this technique may be of interest in itself, as one method to identify historical de-
velopment in a rapidly-changing cityscape and it may be of use for alteration and repair work,
which requires an understanding of hidden structural elements. As a historical method that de-
pends on knowledge of local building construction and that often has a limited time-frame in
which it can be used for any given site, its use tends towards the design and construction profes-
sionals rather than historians.
The two case studies below look at rowhouses and industrial loft buildings in Manhattan.
These buildings are individually undistinguished; there is generally little surviving documenta-
tion of their original design and later alterations. Most official records are discarded after demoli-
tion, and third-party sources typically provide little detail. For example, the fire-insurance maps
that are, in some cases, the only third-party documentation of minor buildings in Manhattan pro-
vide no physical information other than overall plan dimensions and basic materials of construc-
tion such as wood interior structure or “fireproof” interiors. (Sanborn, 1910)
CONTEXT
In the absence of historic context, archeological techniques are limited to conclusions that
can be drawn from physical processes. For example, continuous vertical joints in brick walls may
represent the joint between different eras of construction or, as a special case of different eras,
the infill of a window. Such inferences are useful in determining history from the building itself,
but are limited by the presence of non-ambiguous remnants.
Contextual knowledge that can be applied to broaden the application of the techniques are the
eras of construction of various building types common to the location, the types of construction
materials used at the locations and their eras of use, and common geometric configurations of the
building types. This list of context items is similar to the descriptions of vernacular architecture,
but applies to building types that are not ordinarily included in the “vernacular” label. The con-
cept of vernacular has been extended as far as skyscrapers to address generic building types re-
sponding to local conditions, and is a useful framework to address local building types. (Willis,
1995)
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D. Friedman
Case Study Context
The case studies both show the replacement of 19C rowhouses in Manhattan with early 20C
industrial lofts. Both building types were constructed in the thousands and are still present in
large numbers today.
The construction of rowhouses in Manhattan began in large numbers in the 1830s and contin-
ued past 1900. The mature type, as constructed between 1860 and 1900, consisted of a three- or
four-story building with a high basement. The exterior walls were brick in common bond
(stretchers with headers every sixth or seventh course), often faced on the street facade with
brownstone (a soft local sandstone), and the interior structure was wood. The standard New York
lot is 25 feet by 100 feet (7.6m x 30.5m) but the developers of rows of houses often broke up the
lots in simple-fraction multiples (e.g., subdividing four lots into five 20-foot-wide houses). The
floor and roof joists ran side-to-side and were headered around the chimney and stair openings.
Some details were more specific to New York. For example the high basements required high
entry stairs (“stoops”) that were typically located in areaways created by setting the front of the
house back from the street lot line. The stairs switched back against one side wall and fireplaces
and their chimneys were located against one side wall, but the two were not necessarily located
against the same wall. Also, the interior chimney projections that carry the grouped flues from
multiple floors have single-wythe interior partitions and are separated from the building interior
by a single wythe of brick.
The most important aspect of rowhouses is in their name: if we see one rowhouse, we can
assume that it was originally part of a row. Since the houses in a row were built simultaneously,
the side walls between houses of a row are party walls that straddle the side lot lines.
The construction of mid- and high-rise loft buildings in New York began in the 1830s and
evolved through several distinct types. The type under consideration here is the last, chronologi-
cally: the high-rise buildings constructed from around 1900 to 1930. There buildings have steel
frames carrying concrete floors and brick curtain walls. The street facades may have the brick
faced with terra cotta or precast concrete veneer.
While there have been building laws since the founding of New York in the 17C, there has
been a formal building code in force since 1882. Many aspects of the early codes are useful in
examination (e.g., the mandated wall thicknesses in force until 1901) but three regulations are of
specific interest here. First, when a new building was constructed adjacent to an existing chim-
ney, it was the responsibility of the owners of the new building to extend the chimneys upward
so they ended above the new roof. Since the extensions may be very tall, the extensions are sup-
ported as part of the new building structure rather than resting on the existing chimney in the
older building. (Code, 1922) Second, it is legal to build windows on side lot lines, as long as they
are fire-rated, but the owner of a building with lot-line windows has no legal expectation that
those windows will remain usable. The owner of the adjacent lot may block such windows with a
building that meets the general zoning requirements. (Berger, 1987) Third, since the adoption of
an earthquake design code in 1995, it is no longer possible for new buildings to be constructed
directly abutting existing buildings. Rather, seismic gaps on the order of 1½ inches (3.8cm) must
be left between new buildings and side lot lines or existing buildings. (Local Law, 1995)
CASE STUDY 1: GENERAL ISSUES
A large percentage of lots in Manhattan are now occupied by the second or third building to
be constructed on them. Both case studies show the effect of loft buildings replacing rowhouses,
which was common in many neighborhoods.
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Above-Ground Archaeology of Demolished Buildings
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Figure 1: Overall view of the west wall of 14 East 17th Street. The parking lot is the site of 12 East 17th Street.
D. Friedman
Figure 1 is a view of the west face of 14 East 17th Street taken from the northwest. The street
(north) facade of 14 West is to the left of the photograph view (marked A), and the west wall is
on the west lot line. The entire outline of the now-demolished 12 East 17th Street can be seen as
remnants on the wall. The west wall of 14 East, a steel-framed building, was constructed incor-
porating the party wall that was shared by the original 14 East (a rowhouse) and the similar non-
demolished rowhouse at 12 East 17th Street. The center-of-plan, side-to-side roof ridge (B) of the
houses, creating slopes to the front and back, mark these houses as constructed in the 1850s or
earlier, as later houses typically have a front to back single slope roof. Note that front facade of
the rowhouses is set back from the sidewalk lot line, so that there is new curtain wall in front of
the old party wall as well as above and behind it.
The houses were three stories with an attic and basement: the first floor elevation at the top
of the stoop is visible as nearly a full story above grade. The two original chimneys are intact for
their full height to the roof, with their bottoms supported on the original corbeled brick supports
at the basement level. The original chimneys and later extensions are intact above the roof line.
The rear extension of the house (C), which was one story high above the basement, was probably
original as it shares the identical corbeled chimney-support detail (D), but the chimney in this
area was altered, as it does not match the other chimneys or the width of the chimney masonry
below. The two lot-line windows for 14 East that are within the party wall (E) were cut after 12
East was demolished and do not match the typical window locations for 14 East’s original win-
dows above the old 12 East roof. The stairs in 12 East must have been on the west side, as joist
pockets (see figure 2) are visible across the entire length of the wall.
Figure 2 shows that the hearth opening (F) has been infilled, as have the joist pockets (G).
The joists rested on an a wood sill plate embedded in the brick (H), and there is another wood
strip (J) embedded three courses above the joist tops to serve as a nailer for the baseboard mold-
ing. The infilled door on the right (K) was probably only open during construction of the 12 and
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Figure 2: Close up of the west face of 14 West 17th Street.
Above-Ground Archaeology of Demolished Buildings
14 East rowhouses: such doors were common for easy passage of construction materials between
buildings in the row without having to use more than one set of stairs, the single-course arch is
extremely rare as a support over permanent opening, and the location of the base of the opening
at the baseboard nailer suggests coordination with the original construction.
CASE STUDY 2: THE GHOST OF A GHOST
Figure 3 shows a complex site, with two extant buildings, three that were demolished shortly
before the photograph was taken, and four that were demolished roughly 90 years earlier.
This picture, from January 2004, was taken shortly after the demolition of 505 and 507 Fifth
Avenue. 503 Fifth Avenue had been demolished roughly ten years earlier. The removal of these
buildings created a vacant lot (now occupied by a new building) bounded by 509 Fifth Avenue
(L) to the north and 1 East 42nd Street (M) to the east. 505 and 507 Fifth Avenue had been steel-
frame loft buildings constructed in the 1910s and roughly the same size as 509 Fifth Avenue. 503
Fifth Avenue had been a heavily-modified rowhouse.
Remnants are visible on the south wall of 509 Fifth for most of its 12 stories, on the north
wing of 1 East 42nd (N) for the same height, and on the south wing of 1 East 42nd (O) for roughly
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Figure 3: Overall view of the northeast corner of 42nd Street and Fifth Avenue from the southwest. The building on
the left is 509 Fifth Avenue, the building on the right is 1 East 42nd Street.
D. Friedman
four floors. There are two distinct sets of remnants on the south wall of 509 Fifth: rowhouse-
style markings (P) up to roughly four stories, and a more general scarring (Q) above and behind.
The analysis of this site is best presented as a chronology of the construction and demolition:
•Mid-1800s, rowhouses were constructed at 503, 505, 507, and 509 Fifth Avenue. (Note
that the row may have extended further north than 509 Fifth Avenue, but the site under
examination does not provide any information about the history of buildings north of 509
Fifth.) The chimneys for the houses’ fireplaces were located on their north side walls.
(The date is based on the location and height. The chimney location is based on the 1910s
chronology – see below.)
•Between the mid-1800s and the 1910s, the front(s) of the 507 and/or 509 Fifth
rowhouse(s) were extended to its front (west) lot line, probably as part of a conversion to
commercial use. (The front extension is visible in the low-rise remnants on 509 Fifth.
•1910s, the 507 Fifth Avenue rowhouse was demolished and replaced by a 12-story loft
building. The party wall of the 509 and 507 Fifth Avenue rowhouses was incorporated
into the north curtain wall of the new 507 Fifth Avenue. The new building extended to the
north, east, and west lot lines for its full height. There may have been set-backs or light-
courts at the south wall. There were windows in the new north curtain wall above the roof
of the remaining 509 Fifth Avenue rowhouse and east of its rear (east) wall. (The new 507
Fifth was built before the new 509 Fifth because the window remnants on the south wall
of 509 Fifth have no lintels and show no break in brick coursing or layout and are there-
fore imprints of window openings in an adjoining wall rather than infilled windows in the
extant wall. If the chimneys visible in the old party wall were part of 509 Fifth, they
would have been extended upward and remnants of the extension would be visible. Since
there are no such chimney extensions, the chimneys belonged to the 507 Fifth rowhouse
and the row had chimneys on the north walls.)
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Figures 4 and 5: Close-ups of the remnants. Figure 4 shows the 507 Fifth window imprints on 509 Fifth. Figure 5
shows the shorter 1 East 42nd windows above the 507 Fifth parapet.
Above-Ground Archaeology of Demolished Buildings
•Later in the 1910s, the 509 Fifth Avenue rowhouse was demolished and replaced by the
extant 12-story loft building. The party wall that had been shared by the 507 and 509
Fifth Avenue rowhouses was incorporated into the south curtain wall of the new 507 Fifth
Avenue. The north-wall lot-line windows of the 509 Fifth Avenue loft building were
blocked off. (The remnants on the south wall of 509 Fifth are consistent with blind-built
brick, when the masons only have access to one side of a wall during construction.)
•1910s, the 505 Fifth Avenue rowhouse was demolished and replaced by a loft building.
•Before the 1920s, 503 Fifth Avenue was either extended to the east, filling its original
rear yard, or a second building was constructed on the rear of the lot. (The remnant on the
west wall of the south wing of 1 East 42nd do not match the original house, which fronted
on Fifth Avenue and had a rear yard.)
•1920s, the steel-frame office building at 1 East 42nd Street was built. The east lot-line
windows of the 507 loft building were closed. (The 1 East 42nd windows directly above
the parapet line of 507 Fifth are shorter than nearby windows because of the parapet.).
•1990s, 503 Fifth was demolished.
•2003-2004, 505 and 507 Fifth were demolished. The old 507/509 Fifth rowhouse party
wall was tied to the frame of 509 Fifth for stability because there would be a seismic gap
between its south face and the new building to be constructed on the 503-507 Fifth lot.
The most notable portion of this history is that the 507/509 party wall survived the demoli-
tion of both buildings that it was constructed with. There was no time when it could have been
demolished without exposing the interior of an occupied building.
CONCLUSIONS
It seems odd to discuss the use of archeological techniques to investigate buildings con-
structed in the 1900s, and documentary evidence of modern buildings is of course a useful source
of information. However, in circumstances where documents are not available because they
never existed (e.g., most rowhouses never had formal design drawings), have been destroyed
(e.g., the New York Department of Buildings policy of disposing of paper records when a build-
ing is demolished), or are inaccessible (e.g., the design drawings for loft buildings may be in pri-
vate firms archives), the use of these simple observational methods can add a significant amount
of information regarding the history of a site.
REFERENCES
[1] A. Boato and D. Pittaluga, “Building Archaeology: A Non-Destructive Archaeology.” G.
Nardoni, Proceedings of the 15th World Conference on Nondestructive Testing, Roma
(Italy) 15-21 October 2000, International Committee for Nondestructive Testing, 2000.
[2] n.a., Insurance maps of the City of New York, Borough of Manhattan. Sanborn Map Com-
pany, 1910.
[3] C. Willis, Form Follows Finance, Princeton Architectural Press, p.19ff, 1995.
[4] n.a., New Code of Ordinances of the City of New York, Chapter 5: Building Code, §392.9.
The Banks Law Publishing Company, 1922.
[5] G. Berger, “TPPN #10/87” Permissible Openings in Exterior Walls.” New York City De-
partment of Buildings, 1987.
[6] n.a., Local Law 17/95: The New York City Seismic Code. New York City Council, 1995.
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