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T W E N T Y S E C O N D E D I T I O N
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3.3
STRUCTURE & FABR I C :
ME TAL ,
WOOD & GLASS
the problem. By the end of the century these
supply issues had influenced a shift from oak,
as the most commonly used constructional
timber, to softwood.
However, availability was only one of a
number of limitations that had to be overcome
to meet the need for new secular timber
dwellings of a less important nature. These
included the size of available timber and issues
concerning the seasoning, conversion and
workability of oak. Together, these factors
had a direct bearing on the growing trade of
imported softwoods into England for use in
construction.
The carpenter would have been familiar
with these constraints, discussed in more detail
below, which influenced the size and character
of timber frame constructions.
Availability of timber
English
expansionism overseas and the war with
Spain gave the navy shipyards first call on
any quality timber. Navy surveyors became
increasingly aggressive in their demands for
quality timber (defined by its length, soundness
and dimension). A major maritime power for
many centuries, England guarded its timber
supplies jealously, sometimes even going to war
to protect import routes.
Size of available timber
The size of a
building that could be constructed from timber
was dependent on the lengths of straight timber
that was available, as outlined above. With
the depletion of standards grown in managed
woodland, the carpenters were increasingly
reliant on field oaks for the largest posts and tie
beams, but with branches starting lower down
the tree, long straight lengths were increasingly
difficult to find locally.
Seasoning, conversion and workability
Seasoned oak was much harder than
green oak and could not be easily worked,
so oak tended to be worked in its green
state. While the subsequent shrinkage and
distortion of the oak frame contributed
to its stiffness, dimensional instability
also posed significant problems.
Softwood, by comparison, dries far
more quickly than oak and this reduces its
weight and helps to keep it stable. Excellent
softwoods were also readily available from
abroad. Vast tracts of virgin conifer forest
were easily accessible from the Baltic.
Never previously harvested, the trees had
few branches low down and had very large
trunks, so long lengths were available
without knots (‘clear’ grades). As they had
grown in a cold northern climate with short
summers and long winters, the growth rings
were tighter and the timber denser than in
home-grown softwoods, particularly those
from southern England.
Although there was a well-established
timber trade between the east coast of Britain
and the Scandinavian and Baltic ports by the
16th century, it was not until the middle of the
17th century that imported softwoods became
a replacement for the depleted resources of
England’s oak forests. Following the Great Fire
of 1666, large quantities of softwood timber
were imported for the rebuilding of London,
and for the estate building that developed to
the west of the city from the 17th century.
THE SOFTWOOD BOOM
The record demand for house building in
18th-century London was an indicator of the
nation’s prosperity. The demand for buildings
resulted in a demand for timber; that timber
was pine, felled in Poland and sent to England
through the Baltic ports.
The soaring popularity of imported
softwood was driven by its quality and
availability as well as favourable transport and
conversion costs. The quality of slow-grown
old-stand timber such as
Pinus Sylvestris
that
was cut inland and sent down river to the
Baltic ports of Memel and Riga was recognised
by architects and craftsmen of the period.
Contemporary specifications (for example by
English architect Sir John Soane) called for
pine and fir from these ports, including Memel
and Riga Fir.
Slow-grown timber with tight growth rings
and vertical grain was used extensively for
quality joinery such as doors, door-frames and
box-sash windows.
From the 17th century imported softwood
timber was available from Norway and
the Baltic, cut to size using water-driven
frame saws. This reduced transport costs
and enabled carpenters to access timber
with larger sections (baulks). In the 18th
century the use of softwood in carpentry for
trussed roofing, trussed beams and trussed
partitioning became commonplace. The
trussed elements of 18th-century building
construction were designed to be of a
structural nature and were adopted as a result
of architectural influences from Italy where
a wider expanse of ceiling was fashionable in
the principal rooms.
The mid-18th century saw the publication
of many illustrated books promoting new
structural and decorative joinery techniques.
The principles of trussed roofing, trussed
partitioning and trussed beams were well
illustrated in books such as Francis Price’s
A Treatise on Carpentry
(1733), which were
produced in great numbers for the craft. The
demand for affordable technical literature
such as this demonstrates how 18th-century
craftsmen and professionals became engaged
in a quest for knowledge in the fields of
construction and architectural detailing.
Pattern books also conveyed fashionable
London’s architectural styles to the wealthy
in all parts of the kingdom and eventually had
the effect of regularising architectural style
in England through the gentrification of the
older properties in villages and towns.
CONSERVATION AND REPAIR
OF SOFTWOOD JOINERY
Conservation through repair is an ethic much
spoken of, but with regards to the repair of
external joinery of historical importance,
many people fail to appreciate just how positive
and permanent a well-executed repair can be.
One of the most common historic
external joinery elements is the box-framed
vertical sliding sash window. Neglected rotten
window frames are often seen as a burden and
simply replaced. However, they can usually
be repaired (the rot in softwood joinery is
actually often the result of poor maintenance
or previous sub-standard repairs), saving both
money and well-made historic joinery.
To encourage owners to repair (where
possible) rather than replace, it is necessary
for craftspeople and conservators to impart
confidence in the longevity of a well-repaired
item. This requires the relevant knowledge
to specify the correct repair materials and
expertise in the appropriate craft techniques
such as the scarfing and joining of new wood
to old.
Once a good repair is completed it
will serve for as long as the original item
is maintained and kept in working order.
Given that joinery items can almost always
be repaired, what is needed to achieve a
successful repair?
One of a pair of posts showing the thickened end of
the jowl, formed by the widening of the trunk close
to the ground. The end face of the wall plate can be
seen (upper left), fixed with a post-head tenon and
peg. The tie beam is just visible at the top of the post
(upper right). The paler wood at the right-hand edge
of the post is sapwood from the outer edge of the tree.
Slow-grown old-stand Baltic pine with typically tight grain
The base of a softwood post in a 17th-century timber
frame house in Rayleigh, Essex which was converted
from managed woodland timber: it shows faster
growth in the early years (closer to the centre), with
wide early wood growth rings and tighter late wood
being produced each year. The tighter growth rings
towards the outer edge of the tree indicate slower
growth before it was felled.