NEW WORK IN HISTORIC PLACES OF WORSHIP - English Heritage

NEW WORK IN HISTORIC PLACES OF WORSHIP
NEW WORK IN HISTORIC PLACES OF WORSHIP
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Lighting
The design of a lighting scheme and the light fittings
themselves can have a positive impact on the aesthetic
values of an interior as well as being functional.
Uniformly bright lighting throughout a building will not
be in keeping with the character of an interior that was
historically lit by daylight, supplemented by candles,
oil or gaslight as necessary. Historic decoration and
architectural detailing will have been designed to be
seen in such conditions. The most sympathetic lighting
therefore will simply reinforce natural light in the
daytime, while night time lighting will reflect historic
methods of illumination. Where advice on new lighting
is needed there are considerable advantages in seeking
it from independent consultants rather than from
lighting suppliers or contractors.
Changes in lighting regimes and technology can make
an important contribution to the building’s energy
efficiency. European Union directives are steadily
reducing the availability of the most inefficient forms
of incandescent lamps (i.e. light bulbs) so new light
sources will need to be found for places of worship
over the next few years. The cost of purchase, length
of life, quality of light and appearance of the lamp are all
considerations in choosing which type of lamp to use.
New lighting should be installed in a manner that
minimises physical impacts on historic fabric and
reduces visual intrusion. Accessibility for maintenance
is also a major consideration. Pendant lighting is often
a practical and sympathetic means of providing
functional lighting and can be designed to be an
adornment to the building. Spot or flood lighting is the
most common alternative to pendant lighting, and can
sometimes be employed to dramatic effect, although
the equipment can be obtrusive and its location needs
careful consideration.
External floodlighting schemes should avoid
causing light pollution and may not be appropriate,
particularly for isolated rural churches. Archaeological
advice may be required in respect of sunken lamps
and cabling routes.
BsEST Practice 5: Principles of Conservation
Practice [lighting] (2010)
External Lighting for Historic Buildings (2007)
Energy efficiency
Historic places of worship are unlikely ever to equal the
environmental performance of new-build structures,
designed in conformity with modern Building
Regulations. Nevertheless, more energy efficient use of
buildings can normally be achieved and congregations
wishing to address this issue are advised to draw up
a comprehensive energy strategy for their place of
worship and associated land and structures. This should
identify measures to reduce the existing level of energy
use, which typically have little impact on the significance
of a building. Such measures might include:
• changing the patterns of heating and lighting in the
building and controlling them more efficiently
• upgrading equipment such as boilers and light bulbs
• the provision of better insulation and the elimination
of draughts (without impeding necessary ventilation)
Government planning guidance recognises the
desirability of taking measures to respond to climate
change, but requires that the public benefits of
renewable energy projects are weighed against any
harm to the significance of a listed building or other
designated asset. Some measures which might be
suitable in other contexts, for instance secondary
glazing, are unlikely to be sympathetic to an historic
place of worship and we would discourage their use.
As an adjunct to the installation of efficient heating and
environmental controls, micro-generation equipment
such as solar panels can be beneficial for overall energy
efficiency. In general, we would support the provision
of micro-generating equipment if the visual impact
is minimal, the installation of the equipment causes
minimal damage to historic fabric and is reversible and
the need for it can be demonstrated in the context of
the energy strategy for the place of worship.
Energy Efficiency and Historic Buildings (2011)
Microgeneration in the Historic Environment (2008)
www.climatechangeandyourhome.org.uk
Types of renewable energy generation
(microgeneration)
The following paragraphs summarise English Heritage’s
views on the methods of microgeneration most
commonly considered for use at places of worship
Ground source heat pumps
In many places the ground disturbance necessary for
ground source heat pumps – either a deep pit or a
large, shallow area – will have serious implications for
archaeological remains. This is likely especially at sites
which have been occupied for several centuries. An
archaeological assessment of the affected area should
be made at an early stage to find out what
the constraints are. Ground source heat pumps
generally work well with underfloor heating systems
(see p.15).
Air source heat pumps
Minimising visual impact and damage to historic fabric
caused by air source heat pumps, inside and outside a
place of worship, can be very difficult and as a result
we discourage their use in most cases. They can
sometimes be installed in a church tower, if there is
a silence chamber or other such space that is wellventilated;
otherwise, heat exchange units outside the
building would need to be screened or positioned in
such a way that their visual impact is minimised. With
ingenious use of existing service runs and breaches in
masonry it might be possible to make the necessary
pipework and ducting less obtrusive and physically
damaging. The location of condenser units inside the
building would need to take account of monuments
Other piped services
The provision of toilets or kitchen facilities will
require water, drainage and ventilation. A prior
archaeological assessment will usually be required
in order to establish the impact of such installations.
Subject to archaeological advice, these should be
routed underground rather than directly through walls.
The use of composting or macerating lavatories can
remove or reduce the need for drainage trenches.
In rural buildings where use is not heavy and where
space allows, the Trench Arch system can avoid deep
excavation and complex drainage.
Ventilation for toilets and kitchens can often be
discreetly provided, for example, within the upper
stages of towers, by introducing mesh grilles into
windows or flush, cast-metal or stone-tile grilles into
walls, or by setting the vent-pipe back in the wall and
fitting stone or slate louvres. New ducts drilled through
historic masonry should be avoided wherever possible,
as should external fan units and cowls.
and other significant features of the interior. Such
systems are noisy in operation (similar to the noise of
an air-conditioning unit) and usually require planning
permission from the local planning authority.
Solar panels and solar ‘slates’
Since roofs are often highly visible and make a major
contribution to the character of the building in its
setting, putting solar panels or slates on them can
potentially cause substantial harm to significance. The
possibilities for installation will depend upon the form
of the roof and the situation of the building. Shallowpitched
roofs behind parapets and valley roof slopes
are most likely to be able to accommodate solar panels
with minimal visual impact. An alternative may be a
ground-mounted solar collector or finding another, less
sensitive building on which to put the equipment.
Even when carefully designed and managed, the
installation, maintenance and eventual decommissioning
of solar electric panels or solar slates is likely to cause
some damage to the existing historic fabric of a place
of worship. To mitigate this it is important that the
means of fixing, maintenance and eventual removal of
the panels or slates are planned and agreed in advance.
Equipment should be located so that it does not
impede rainwater disposal or hinder maintenance work
such as cleaning gutters.
Solar Electric (Photovoltaic) Panels and Slates on Listed
Places of Worship (2011)
Small-scale solar electric (photovoltaics) energy and
traditional buildings (2008)
Drainage and groundworks
A degree of dampness is not uncommon in the walls of
old churches, especially where external ground levels
have risen over time. Ground lowering (sometimes
associated with the laying of drains) is not normally
recommended as a remedy for this since it is likely to
damage archaeological features, foundations and wall
surfaces, and may lead to excessive drying out with
subsequent cracking and even subsidence.
Rainwater is best disposed of by downpipes to gulleys
and soakaways, thereby getting water away from the
walls of the building. Dampness is best managed by
regular clearance of gutters and downpipes, good
ventilation and by allowing for permeability in the wall
surfaces through the use of ‘breathable’ mortars, plasters
and finishes.