Legacy System Information
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Legacy System: RSM
This list entry does not comprise part of an Asset Grouping. Asset Groupings are not part of the official record but are added later for information.
Legacy Record - This information may be included in the List Entry Details.
Gunpowder was the only explosive available for military use and for blasting
in mines and quarries until the mid-19th century. Water-powered manufacturing
mills were established in England from the mid-16th century, although powder
had been prepared by hand for at least 200 years. The industry expanded until
the late 19th century when high explosives began to replace gunpowder. Its
manufacture declined dramatically after World War I with British production
ceasing in 1976.
The technology of gunpowder manufacture became increasingly complex through
time with the gradual mechanisation of what were essentially hand worked
operations. Waterwheels were introduced in the 16th century, and steam engines
and water turbines from the 19th century. Pressing and corning were also
introduced between the 16th and 19th centuries to improve the powders.
Pressing improved the explosive power of the mill cake and corning broke the
pressed cake into different sizes and graded it with respect to its fineness.
Additional techniques were developed throughout the 17th, 18th and 19th
centuries to improve the quality and consistency of the finished product, and
this in turn resulted in a variety of types of powders; ranging from large
coarse grained blasting powders (used in mines and quarries) to fine varieties
(used, for example, in sporting guns).
Gunpowder manufacturing sites are a comparatively rare class of monument with
around 60 examples known nationally. Demand for gunpowder centred on the
London area (for military supply), other ports (for trade) and the main metal-
mining areas. Most gunpowder production was, therefore, in Cumbria, the south
west, and the south east, around the Thames estuary. The south east of England
was perhaps the most important of these areas. The first water-powered mills
were established here from the mid-16th century onwards and many of the major
technological improvements were pioneered in the mills at Waltham Abbey and
Faversham. All sites of gunpowder production which retain significant
archaeological remains and survive well will normally be identified as
The Waltham Abbey gunpowder mills are important for three main reasons:
because many of the processes used in this international industry were
invented and developed at Waltham, because the works survive in a remarkably
complete state and because many of the structures themselves are rare
nationally and internationally.
Most of the structures on the site survive in a remarkably complete state, in
several cases only the matchwood components of the buildings are absent.
Unusually a sequence of complete transport and power systems which connect
the structures also survives in a complete condition. Although some similar
structures are known at other sites, the Waltham examples are all in a much
more complete state than elsewhere and quite a number (such as the press house
and the Quinan Stove, for example) are thought to be unique survivals. Not
only do the structures survive well, but several of them (like Smeaton's Mill,
for example) were the prototypes for technologies which subsequently became
standard and were exported around the world. Since the site survives so
completely it is possible to trace the entire history of the gunpowder
industry through the alterations and adaptations made to the structures here.
For an industrial site there is also a remarkable collection of documentary
information which, most unusually, allows the functions of the various
buildings and structures to be understood in great detail.
The Waltham Abbey site is further distinguished from others by the quality of
the surviving remains of the guncotton, nitroglycerine and cordite industries,
which replaced gunpowder for most military purposes at the turn of the 19th
century. Again the structures of these related industries survive in a near
complete condition. Many of them are thought to be unique to this site (the
drying kilns of the late 1870s, for example) and, as with the gunpowder
industry remains, there are several structures which were the earliest
examples in the world, within which the whole industry was invented and
developed. These structures also have accompanying documentation which adds to
the significance of the surviving remains.
Finally, the site at Waltham has several other features of interest such as
the unique surviving components of the tetryl works and the interesting
adaptations undertaken to the site during the initial years of the British
Legacy Record - This information may be included in the List Entry Details.
The monument is situated on the northern outskirts of Waltham Abbey and
includes intact buildings, ruins, earthworks and buried remains of parts of
the Royal Armament Research and Development Establishment, formerly known as
the Royal Gunpowder Factory. The remains are associated with the manufacture
of gunpowder, guncotton, nitroglycerine, cordite paste and tetryl, and include
a number of ancillary buildings and structures associated with these
manufacturing processes. Intact buildings, ruins, earthworks and buried
remains of parts of a complex concerned with producing and testing modern high
explosives, parts of an extensive water management system and parts of an
associated tramway and railway network are also included. The scheduling
occupies two separate areas.
The site is set within and around a series of watercourses, most of which are
man-made and channel the River Lea as it flows from N to S. Although the
manufacture of gunpowder in the Waltham Abbey area dates back to the 1560s,
there is no documentary evidence for production at this site before the mid-
17th century. Between 1702 and 1787 the site was in the possession of the
Walton family who developed many improvements to the gunpowder manufacturing
process here. Cartographic evidence from this period indicates that these
early works occupied the area known as Millhead to the W of Middle Road and
Powdermill Way in the southern part of the first area of protection. Here the
mills and other buildings were set on either side of a large leat fed by a
branch of the Lea. Water from this leat (the Millhead Stream) was drawn off at
regular intervals along its course to power the mills and was returned to
the river by means of two parallel tailraces either side of the leat. These
mills included stamping mills which blended the raw materials of saltpetre,
sulphur and charcoal, a corning house and a glazing house, and a number of
stoves for drying the finished product. There were also associated ancillary
buildings, including powder magazines.
Some of these early mills were horse-powered and, in 1963, construction work
in the Millhead area recovered the remains of at least two horse mills
surviving beneath the ground surface. An engraving of the site in 1735
indicates that, by this date, water-powered mills either side of Millhead
Stream were already in use, but water-power did not entirely replace horse-
power until 1814. A number of mills along Millhead Stream, including Smeaton's
Mill and Head Mills, have been located during excavation work and recent
ground clearance. These remains indicate structures with a complex history
retaining evidence for several phases of construction. The remains of
Smeaton's Mill were found to include the brick foundations of a mill building
which also forms the inner edge of the tailrace situated to the E of Millhead
Stream. Within this mill a central wheelpit is visible, although rubble-
filled. Irregular scarps on the platform between the E tailrace and Millhead
Stream indicate the presence of further building remains beneath the ground
surface. The remains of the mill buildings in the Millhead area are also
visible above ground. The Dusting House, for example, in use between the early
18th and mid-20th century, shows a number of alterations and rebuilding phases
and is represented by brick foundations either side of a central wheelpit. The
wheel was powered by water from Millhead Stream and its flow was regulated by
a sluice gate. The Dusting House was latterly provided with a concrete
traverse (blast wall). Traverses, both standing structures and foundations,
are present throughout much of the site and are constructed from a number of
different materials, including brick, earth, and corrugated iron. They served
an important function in minimising the damage caused to buildings by
explosions elsewhere on the site. A number of roofed buildings also survive
within the Millhead area, including the 18th century offices, a powder and
barrel store, and washing house. These buildings are of exceptionally rare
types and are intrinsic to the site's history and development. They are not,
however, included in the scheduling but are protected as Listed Buildings.
An important surviving group of steam-powered incorporating mills, the
earliest dating from 1857, is situated to the E and SE of the area of the
scheduling. This part of the site also includes associated expense magazines,
ancillary structures and two accumulator towers. These buildings are Listed
Grade II, II* and I and are not included in the scheduling.
In 1787 the site was purchased by the government who implemented an extensive
programme of modernisation. Map evidence indicates that by the early 19th
century the site had expanded northwards and eastwards, but the Millhead area
continued to play an active role in gunpowder manufacture. In the N part of
the site, served by an extension to the canal system, horse-powered corning
houses were constructed. In the NE part of the site an oval, battered brick
traverse, present on an 1806 map, remains standing. It was originally
associated with a gunpowder corning mill that fell into disuse by c.1827. The
mill was re-equipped with a water-powered hydraulic pump and a gunpowder press
in the mid-19th century. The structures associated with this press include a
single storey brick building which retains its water-driven hydraulic pump and
its cast-iron water-wheel attached to the external S wall. To the N of this
structure are the foundations of the press house, which retains its cast-iron
gunpowder press in situ.
At the N extremity of the site, well away from other danger buildings and
served by the canal, the finished powder was stored in the Grand Magazine. The
final building on this site was of brick and is now partly ruined.
The saltpetre refinery which served the mills is situated approximately 265m
to the S of the Millhead area in the second area of protection N of Highbridge
Street; map evidence indicates that refinery buildings were present at the
site by the 1780s. Here, the saltpetre was prepared, concentrated and
crystallised ready for incorporation with the other raw materials. The buried
remains of the refinery survive beneath the ground surface and are included in
In the early 19th century, after the sale of its factories in Faversham and
Ireland, the Royal Gunpowder Factory at Waltham Abbey became the only
government owned gunpowder manufacturing site in the country.
By the middle of the 19th century there was a growing interest in two new
explosives, guncotton and nitroglycerine, and in 1863 an experimental plant
for the production of guncotton was set up at the site. Cartographic evidence
indicates that this plant was situated on the site of the original saltpetre
refinery and included a guncotton processing building. It is thought that some
of the buildings associated with the saltpetre process were also adapted and
The production of guncotton increased dramatically and in 1885 a new site was
acquired at Quinton Hill to the south of Waltham Abbey for a larger capacity
plant for the production of guncotton and nitroglycerine, a liquid explosive.
In 1891 the manufacture of cordite, a mixture of guncotton and nitroglycerine,
was introduced at the main site. The importance of the role of gunpowder, both
as an explosive and as a propellant declined with these new innovations and,
as a result, a number of buildings formerly used for gunpowder manufacture
were adapted and new buildings erected for the production of cordite.
In 1895-6 a nitroglycerine factory was also built in the northern part of the
site to cater for the increased demand for cordite. The manufactured guncotton
from Quinton Hill was transported by barge to the main site where it was dried
in stoves, mixed with nitroglycerine and washed to produce cordite.
The remains of this process survive right across the site, particularly in the
N and NE. Some of the most prominent features are the standing and earthwork
remains of the guncotton drying stoves. These stoves typically survive as
circular brick or concrete walls revetted with an earthen traverse. A timber
round-house was originally located within the centre of these traverses where
the wet guncotton was dried on racks for a period of approximately eight days.
The concrete platform upon which the round-houses were sited is visible within
a number of the stoves and several retain their metal drying racks. In 1936 a
rectangular stove with 18 bays was erected for the drying of guncotton. Known
as the Quinan Stove, it replaced an earlier circular stove and is thought to
be the only surviving example of its type. The drying stoves were heated by
hot, dry air and, in most cases, pairs of stoves were connected by cast-iron
pipes to an associated engine or fan house. This system of pipework survives
in parts and its remains are included in the scheduling. In several parts of
the site the pipes are carried over canals by bridges which are also included
in the scheduling. Many of the fan houses survive in the form of concrete
floor slabs and sandstone blocks which retain vertical mounting bolts.
The system of canals was extended to serve the early guncotton drying stoves,
to transport the wet guncotton to the stoves and to move the dried guncotton
to the mixing houses. These canals survive as partly infilled earthworks and
as buried features. The guncotton stoves, which are aligned NW-SE and lie
adjacent to Cornmill Stream, were also served by a narrow gauge railway
The 1895-6 nitroglycerine factory at the site includes the nitrator, where the
nitroglycerine was produced, washing houses, a wash water settling house,
mixing house and their associated traverses. A number of the support
stanchions for the lead-lined gutters which carried the nitroglycerine from
one process building to the next remain in situ. The nitroglycerine was moved
by gravity and, therefore, the nitrator is situated on one of the highest
points of the factory. In 1941, due to increased demand for explosives during
World War II, a second nitroglycerine factory was constructed in the E part of
the site, known as New Hill. The remains of this factory are similar in
layout and construction to the 1895-6 plant, but it is thought that this
second factory never became operational.
In 1910 a small plant was established at the site for the small-scale
manufacture of tetryl, a booster explosive. The visible remains of this plant
include two pairs of rectangular drying stoves which were built in 1940 and
are situated in the E part of the site, to the S of New Hill. These pairs of
stoves survive as standing buildings separated by breeze-block traverses. The
storage lockers where the tetryl was dried remain within the buildings. The
stoves were served by the light railway network. Other standing and earthwork
remains of the tetryl plant include cleaning houses and a corning house. Part
of the tetryl plant was situated to the NW of the area of the scheduling and
immediately to the W of the site's 1895-6 nitroglycerine plant. These
buildings have been demolished and, as there are not thought to be any
distinctive buried remains of this part of the plant, this area is not
included in the scheduling.
In the early years of World War II, the Royal Gunpowder Factory was in the
forefront of explosives production, but the erection of new larger factories
during this period led to a gradual transfer of production. The contribution
of the Waltham Abbey site declined, with the high explosive RDX and tetryl
remaining as its principal products. The Royal Gunpowder Factory closed in
1945, but reopened in the following year as an experimental station for the
research and testing of modern high explosives and propellants. A number of
existing buildings at the site were adapted and reused for these experiments
and some new construction work also occurred. Evidence for these activities
remains visible throughout the N part of the site, particularly at the New
Hill nitroglycerine factory and within several of the 19th and early 20th
century engine houses. Firing points were established within these structures
and steel plating, to minimise the consequent damage, survives within several
buildings. The internal walls of these buildings are marked as a result of
Seven powder barges and three punts, which transported both the raw materials
and the finished products around the site, survive in the canal beds. These
barges, built of timber, copper and leather, are rare survivals in context and
are included in the scheduling.
Some of the electricity insulators at the site are thought to date from c.1890
and indicate that electricity was being produced at the site prior to the
construction of the central power house in 1914-15. These insulators and the
poles upon which they are located provide important evidence for the early
introduction of electricity at the Waltham Abbey site and they are, therefore,
included in the scheduling. The site's concrete lampposts, which survive
unaltered to an unusual extent, are included in the scheduling as an integral
part of the site's final phases of military and scientific use.
The library and lecture theatre building, built in the 1960s, the late 18th
century superintendent's office and the contemporary mixing house and
saltpetre mill building which all occupy part of the Millhead area; fence
posts, railings, sign posts, fire hydrants and the surfaces of all roads and
pathways are excluded from the scheduling, but the ground beneath all these
features is included.
The site of the monument is shown on the attached map extract.