Archaeology of Historic Timber-framed Buildings
frames exert a powerful fascination and have attracted a great
deal of attention over the last 30 or 40 years. The pioneering
work of researchers such as Freddie Charles, John Smith and Cecil
Hewett has been taken forward by a host of enthusiasts and innumerable
publications. Dendrochronology has given speculation and deduction
a backbone of fact. The Carpenters' Fellowship has provided a
meeting place for young carpenters to swap ideas and pool their
an architect, Smith an RCHM investigator, and Hewett a teacher,
and in those days professional archaeologists had very little
to do with standing buildings. When the Council for British Archaeology
(CBA) was founded in 1943 one of its aims was to promote the archaeological
study of buildings, but that was not achieved until the 1980s: arguably, between the formation of the CBA's Historic Buildings
Committee in 1978 and the Institute of Field Archaeologists' 1993
conference, Archaeology and Standing Buildings.
historians and archaeologists made uneasy bedfellows, historians
accusing archaeologists of amassing expensive and useless detail,
archaeologists in turn showing how their painstakingly detailed
studies had turned many an established history on its head. Architects,
meanwhile, went their own sweet way, blissfully unaware of the
standards established by professionals in the parallel disciplines
of archaeology and conservation; and builders, by and large, couldn't
understand what all the fuss was about - as craftsmen they felt
they had sufficient understanding through empathy with their forebears.
Today, things have improved considerably. The building industry
has taken on board the fact that there are people called archaeologists
and specialist conservators, and good teams have been assembled
for important projects.
of timber-framed buildings developed along its own distinctive
path. In the early days of vernacular architecture - the 1950s,
when the Vernacular Architecture Group was formed and some formidable
intelligence was brought to bear on what was effectively a brand
new subject - the analysis of vernacular architecture was almost
wholly conducted in terms of forms of timber framing. Stone was
only interesting insofar as it reflected the natural geology of
a region, and brick was, well, brick, but timber framing was somehow
alive! Hewett stunned everyone with his focus on joints and the
resulting revision (mostly backwards) of established dates, JT
Smith single-handedly laid down an entire foundation for the subject,
and in the annus mirabilis of 1975 Eric Mercer and Peter Smith
produced their magisterial works English Vernacular Architecture
and Houses of the Welsh Countryside.
gable frame of the Hoop and Grapes, Aldgate, dismantled in
1991 Left: the frame as found, related to horizontal and vertical
datum lines; right: the original pattern of framing reconstructed
the survey and interpretation of a timber-framed building, the
choice of recording method and level of detail always depends
on the purposes for which the record is being made. Timbers retain
in their mortices extensive information about the design of the
building, and this makes it easy to restore the missing parts
of fragmentary timber-framed buildings either on paper or in physical
reconstruction. Drawings can use survey evidence to portray the
original appearance of timber-framed buildings.
It is important to analyse timber-framed buildings in terms of
their component two-dimensional frames. Each frame was pre-fabricated
by the carpenter, and a carpenter's eye would see the component
frames distinctly within the three-dimensional building after
all, the frames were pre-fabricated, with all their joints cut
and trial-fitted. Most buildings were assembled piece-by-piece, not pre-assembled and reared into position.
first step in understanding a building is to 'parse' it against
the 'grammar' of traditional timber-framed construction. First,
the lap dovetail assembly between tiebeam and wall plate (see
illustration) is an almost universal component of framed buildings
in England and Wales (other than cruck buildings), and in analysis
it defines the 'direction' of the building: that is, which is
the cross, or tying member, and which is the longitudinal plate.
Usually, of course, that is obvious from the pitched roof, but
where the roof has been removed or altered the tiebeam lap dovetail
is the best indicator. It also reveals the eaves level, which
can be useful if the building has been heightened. Conversely,
its absence should set alarm bells ringing and prompt immediate
and equally important, is the bay system. Bays are the main link
between structure and plan: they have a structural function in
collecting loads, and a plan function in dividing or articulating
the space. In its classic form, the plan determines bay lengths,
while the bay divisions articulate the plan, so identifying the
bay divisions and measuring the bay lengths is the first step
in laying out the bare bones of the building's system. There are
exceptions, of course - in some buildings, for instance, the roof
has a different bay rhythm from the floors below - but by and
large the bays are the key to plan.
front wall of a pair of semi-detached cottages built in Ashtead,
Surrey, in the 1860s and now reconstructed at the Weald &
Downland Open Air Museum. From top: The frame as originally
fabricated; the frame altered before erection to change the
window positions; front elevation showing the design of the
plastered front, lined to imitate ashlar stonework; and the
front of the cottages as reconstructed at the museum
third feature to look for is the 'upper faces' of the cross frames:
which way do they face? (The 'upper face' is the face used by
the carpenter as the reference face during framing). Where a frame
divides a heated from an unheated room (a very common occurrence),
the upper face of the dividing frame will face the heated room;
and in barns the upper face of each internal cross frames faces
the threshing floor. But while these are the simplest rules, the
varieties and subtleties of the arrangement of the upper face
in various building types are of enduring interest and repay close
attention. The upper face is the face the carpenter 'looks at'
in his mind's eye, so that for us to pay attention to the upper
face is a way of getting closer to his perceptions.
look at the timber, and in particular the way it is converted:
the tool marks and methods of conversion form a pattern which
confirms and amplifies observations of the bays and frames. Using
a powerful torch shining along the surface, look for saw marks
and axe marks: axe hewing marks indicate the outside surfaces
of the tree, and saw marks result either from a cut through the
heart or, for smaller members, from slabbing. Surprisingly often,
inconsistencies in the tool marks are the first indication of
the building in this way will give a pretty good idea of its interpretation,
and the next step is to establish the geometry of the building.
British carpentry is 'scribe-rule' carpentry, in that the surfaces
of timbers at mortices are accepted as imperfect, and the shoulders
of tenons are scribed to fit. However, the three-dimensional discipline
demands that each two-dimensional frame must possess a 'nominal'
plane, which can be related (usually at right angles) to the 'nominal'
planes of its neighbours. These planes are embodied physically
in reference marks called 'plumb and level marks' which the carpenter
created on the upper face of each frame. However, these marks
are often not now visible, and in any case movement of the timber
over the centuries will have destroyed their accuracy, and it
is reasonable to assume that the upper face of each frame represents
the true plane of that frame for the purposes of survey.
job is to ensure that the overall setting-out measurements of
the frames in each of the three dimensions are accurately established;
longitudinal bay lengths, transverse spans and vertical heights
and roof pitch. Bay lengths should be measured between upper faces
of cross frames, and it is important to measure them on both sides
of the building: all too often a surveyor assumes a building is
square, when in fact it was designed and framed at irregular angles.
Similarly it is important to check that the overall span of the
building is constant. Many buildings taper, if only slightly,
from one end to the other.
are missing, their previous existence can be established by looking
for empty mortices or their accompanying pegholes. 'Looking for
pegholes' may caricature the study of vernacular buildings, but
it is not a foolproof method: pegholes can be inserted, and sometimes
original joints were not pegged. Another way is to shine a torch
along the surface to detect the carpenter's setting-out lines,
usually found on the face of the timber, where the pegholes are
seen, or on the adjacent surface in which the mortice was dug.
These lines can be particularly important around window positions,
betraying not only the former existence of a window but also some
of its details. In the end, of course, no one feature ever gives
the full story, and it is the consistency of the overall pattern
that is the most powerful interpretative tool.
As well as
investigating the original frame we may also be interested in
later phases of alteration, depending on the particular circumstances.
General rules are not easy to formulate, but the important thing
is to proceed methodically from step to step. At each stage find
a pattern that you can recognise and rely on, and follow it as
far as you can around the building. For the purposes of explanation,
keep your hypothesis simple: things not known to exist should
not, unless it is absolutely necessary, be postulated as existing.
all this, the information may be brought together on paper. The
first drawing produced can be a diagrammatic plan, showing the
bays, principal posts and upper faces, dimensioned with bay lengths
and span. Such a diagram forms a good summary of a timberframed
this, the component frames of the building can be drawn. It is
often best to tackle the cross frames first, followed by wall
frames and floor frames. Door, window, and stair positions are
the basic keys to interpreting the building. The frames should
be drawn as self-contained objects, rather than as the background
to a cross section, an important difference from the normal disciplines
of architectural drawing.
the main outlines, filling in the secondary framing members, such
as studs, braces, joists, and rafters presents few problems: the
work can speed up because a high level of accuracy is not usually
critical once the overall geometry of the building has been established.
This is not to say that accuracy is unimportant: indeed it is
critical for establishing the overall geometry in the first place.
Minor differences in the size or position of members, even the
setting out of joints, can give crucial information about the
building, and accuracy can still be important for interpretation.
To draw is
an essential step towards understanding: I have to draw in order
to see. Of course it is possible to look round a building and
suggest an interpretation without making drawings, but I never
see the building clearly until my observations have been tempered
with the discipline of making a drawing on paper. Interpretations
not based on drawings tend to become inaccurate as soon as the
building becomes tricky; as a general rule, drawing a building
carefully is a discipline that assists interpretation.
And is there
any experience more enjoyable than sitting quietly in the roof
space of a house, drawing medieval timbers that have hardly been
seen, let alone touched, for two or three centuries, while the
busy world goes on its way outside?
article is reproduced from The
Building Conservation Directory, 2006
is Museum Director of the Weald & Downland Open Air Museum.
For 23 years he was responsible for the research and interpretation
of the timber-framed buildings which form the core of the
museum, and his book Discovering Timber-Framed Buildings (Shire Publications, 1978) remains an indispensable introduction
to the subject. He has played a major part in developing
the museum's building conservation training programme, including
the MSc in Timber Building Conservation.
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