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BCD Special Report
Historic Gardens 2010
15
Restoration
The process identified two key areas where
materials specification was crucial to success:
replacement ironwork and the provision of
new glazing. LEP’s investigations confirmed
that the structure was a combination of
cast iron elements (columns and decorative
friezes), wrought iron elements (glazing bars,
purlins, and fixing straps) and early steel
beams (eaves beams and ridge). In general,
the team’s approach dictated the maximum
retention of original fabric. Where repairs
to elements were required these were to
be on a ‘like-for-like’ basis so that wrought
iron, for example, would be repaired using
wrought iron of a matching quality. However,
where replacement of components was
necessary this was less straightforward.
Wrought iron is simply no longer
manufactured commercially, and only
‘reclaimed’ wrought iron is available. This is
difficult to grade and can vary from good quality
(ships chains) to poor (reclaimed railings). This
clouds the issue of like-for-like provenance.
Allied to this, the supply of true wrought iron
is variable and few sources reclaim the material
in quantity. For this reason it was decided that
replacement components should be supplied
in a contemporary material. Our research
highlighted the compatibility of ‘pure iron’, a
modern material with a similar composition,
structure and properties to wrought iron. Its use
would allow damaged components to be reused
as compatible material for like-for-like repairs.
All replacement components would be clearly
stamped and dated to identify their origin.
The issue of replacement glazing would
prove an even more difficult issue to address. In
conservation terms the aspirations were to use
the most historically accurate replacement glass
possible. However, the practical requirements
for environmental control and safety would also
need to be considered. Given the building’s
intended new use, any measures to address
overheating in summer and cold in winter could
not be ignored. Likewise, the health and safety
implications of overhead glazing in a public
building needed to be fully acknowledged.
Having used a modern Swiss manufactured
glass in a recent conservation project, LEP was
aware that it was possible to source slightly
textured or rippled glass in large sheets with a
nominal increase in the thickness of the glazing
system. It was likely that the original glass
was approximately 4mm thick. To increase
this by any substantial amount would create
issues in terms of the rebate depth of the
glazing bars and their structural capability.
Through detailed discussions with
the manufacturer a system was proposed
which used a similar product in a laminated
form. Unfortunately, this fell victim to
the value engineering exercise that was
necessary to keep costs within budget. As a
compromise, and with the close involvement
of the specialist restoration contractor
(Eura Conservation), it was decided to use
a modern float glass which is overheated as
part of the toughening process, resulting in
a slight distortion to its surface finish. The
float glass does not match the aesthetic of
the more expensive option but its use did
address the safety issues and incorporating
a solar control safety film on the inside also
provided some environmental benefit.
This approach resulted in an overall
thickness of 6mm on inclined overhead
glazing and 10mm on the low level vertical
areas where the use of a more robust
material was considered prudent. The
structural engineers considered that the
existing structure would be more than
capable of accepting any increased loading.
The new glass would allow the proposals
to keep within the budget constraints and
the slight imperfections in its structure
would go some way towards delivering the
softer look of historic glass. The use of an
applied film to address environmental and
safety considerations fulfilled the team’s
responsibilities to acknowledge the practical
issues raised by the building’s new public use.
Stanley Park today
The regeneration of Stanley Park means
that visitors can enjoy the full beauty of
the restored landscape at their leisure and
then retire to the conservatory café where
modern facilities offer refreshment and
comfort. Above this, the restored volume of
the conservatory provides a dynamic new
venue for a range of functions and uses, from
weddings to display and performance.
The enhancement of the park’s fabric
married to the sensitive incorporation
of increased security has provided a safe
environment where all can appreciate
the quality of the original design. More
importantly, the regeneration has restored
local pride in, and a sense of ownership
of, the park and its structures. The cycle
of decline and misuse has been broken
and the park is once again the focal
point of the community it serves.
Client: Liverpool City Council
Architect: Lloyd Evans Prichard Ltd
Landscape architect: Planit EDC
Project manager: 2020 Liverpool
Quantity surveyor: Gleeds
Structural engineer: 2020 Liverpool
M & E engineer: Mouchel
Ironwork restoration: Eura Conservation
Adrian Pearson
RIBA AABC is a
director of Lloyd Evans Prichard, architect
and conservation consultant for the
regeneration of the historic core of
Stanley Park. The author would like to
acknowledge the kind assistance of Liverpool
City Council in preparing this article.
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View of the basement park café which spills out onto the terrace on the north side of the conservatory
The restored conservatory and bandstand in the setting of the new landscape precinct