Issue 48 AUG 25 web - Flipbook - Page 123
Blenheim Orangery
In 2023, Blenheim Palace called for an overhaul of the declining, impractical glazed Orangery roof
with additional repairs to the adjoining Kitchen and Flagstaff, as the roof was thermally inefficient
and unsafe. The aim of this project was to understand, as far as possible, the original conditions within
the Orangery and the construction of the roof to be able to make meaningful decisions for the future
of the space.
The construction of the Orangery started after 1716. The
space was a working area for gardeners, and it is likely that
the interiors would have been very plain. It is unclear
whether the space would have had a ceiling, however
most similar precedent buildings of this era do have
ceilings. The most critical event, which affected the space,
was the fire of the 5th February 1861 which broke out in
the Bakehouse and spread to the adjacent Orangery
leaving only the walls standing. Extracts from an article
at the time refer to ‘the melted lead pouring down so as
to endanger all who attempted to interfere with the work
of destruction’. Following the fire and with the fashion for
Victorian ornamental cast iron structures, the ‘new
panelled roof was made of rough plate glass supported on
iron beams…this resulted in the Greenhouse being top
lit for the first time.’ Unfortunately, phases of repairs and
re-glazing are recorded from the start of the 20C,
culminating in the issues found by the design team.
of the asset. Reinstating a solid roof, consistent with the
research, and plaster ceiling was seen to sustain and
enhance the heritage asset. A new steel structure was
designed with a 30mm tolerance on the Victorian internal
architectural details to house a new insulated slate roof
and fit a new cornice internally. This new internal scheme
was considered to be consistent with contemporaneous
examples of Orangeries.
The works ensured that the carbon impact of the
buildings was greatly reduced. It previously had a very low
efficiency modern glass roof, calculated at an additional
15,600kg of CO2 emissions per year above a solid
insulated roof, which was replaced with high efficiency
insulated slate and lead, also being more sympathetic to
the original design. Overall, the alterations enable and
enhance the ongoing use of the Orangery as a restaurant
for the benefit of visitors and the community, bettering it
both structurally and environmentally and improve the
viability of the World Heritage Site as a whole.
From analysis, the existing glazed roof was considered to
be detrimental to the aesthetic and historic significance
Conservation & Heritage Journal
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