historic building interiors conservation
TRANSCRIPT
HISTORIC BUILDING INTERIORS
CONSERVATION
Dr Donald Ellsmore
Director, Donald Ellsmore Pty Ltd
Convenor, Australasia Chapter
Association for Preservation Technology
ISSUES INSIDE BUILDINGS
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Building have
contents and
occupants
Structural issues
impact on integrity
of interiors
Building envelope isolates
outside from inside
Interior environments
have a close
relationship with the
envelope
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PRINCIPAL CAUSES OF DETERIORATION
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Apart from structural movement
buildings may be affected by other
factors, including:
Human Factors
inherently poor design
poor material selection
user actions
Atmospheric and Climate Action
meteorological factors
atmospheric pollution
Excess Moisture
Chemical, physical and biological
action
METEOROLOGICAL FACTORS
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Storms
Strong winds
Floods
Seismic activity
When a structure is weakened by damage and loses integrity, the rate
of deterioration can increase rapidly.
ENVIRONMENTAL IMPACTS
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Environmental factors include some
which may appear benign but their
incremental effects can be considerable.
Environmental factors include:
Oxidation and corrosion
Electro-chemical reaction
Carbonation
Sulphate attack
Pollutants and contaminants
Soluble salts
Biological action
In well-maintained structures these
factors may be minor but in others
they may become major issues.
PERFORMANCE OF TRADITIONAL BUILDINGS
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The design and functioning of
buildings is something that has
evolved over many years.
Traditional buildings are to an
extent self regulating in matters
such as controlling the impacts
of external climate to provide a
stable internal environment for
human comfort and longevity –
but only when the occupants
use the buildings in the
traditional planned manner.
BUILDING ENVELOPE
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It is commonly found that,
over time, traditional
buildings become ‘improved’
by changes which affect
their ability to function
properly.
Changes which alter the
traditional behaviour of
materials and structures
usually introduce problems.
WATER
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Excess moisture – such as caused
by penetrating or rising damp,
condensation, hygroscopicity, user
actions and natural or man-made
events - is the most widespread and
damaging cause of deterioration and
decay in heritage buildings.
Causes of excess moisture may be
obvious in some situations but not so
in others.
Moisture in building fabric can effect
the health of occupants and the
condition of interior fabric and
contents directly.
ENVELOPE & ENVIRONMENT
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The main difference between
environments indoors and outdoors is
water.
Indoors there is no precipitation water
to wet down surfaces or flush off salts
and contaminants.
Indoors there are fewer pollutant
gases.
Indoors the relative humidity is
normally lower (drier).
Users may introduce water in the
form of condensation and damp
through apparently innocent activities
and/or lack of maintenance.
RELATIVE
HUMIDITY (RH)
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Understanding
Relative humidity
(RH) is key to
understanding
how buildings
(and humans)
respond to
moisture.
UNDERSTANDING RELATIVE HUMIDITY
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To understand Relative Humidity think of
an inflated balloon containing air and a
small amount of water. The ratio of water to
air is the relative humidity within the
balloon (expressed as %).
If the balloon is placed over a flame the air
will expand but the water content will
remain the same. The RH will decrease.
Conversely if the balloon cools the RH will
increase.
The interiors of buildings are like balloons. If they are heated the RH will
decrease. If they are cooled the RH will increase. If water is introduced the RH
will increase etc.
INTERIOR ENVIRONMENT
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The Relative Humidity in buildings is
a function of temperature, moisture
and air movement .
Inadequate air movement or
excessive moisture can lead to
development of high RH, mould,
fungal decay, insect infestations,
condensation and deterioration of
materials.
HYGROSCOPIC MATERIALS
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Cellulose (one of the major constituents of
wood) is a hygroscopic material. It gains
moisture (adsorption) when the RH is high
and looses moisture (desorption) when the
surrounding air is dry.
Dimensional change is the most important
consequence of moisture sorption by
wood.
HOW BUILDINGS RESPOND TO CHANGES IN RH
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All hygroscopic materials expand or
contract in response to changes in
RH, causing structural changes to
building fabric - carpentry, joinery,
furniture and furnishings.
There is a value in maintaining
hygroscopic materials in their
‘historic’ environment.
When buildings are heated or cooled hygroscopic materials will respond
by changing to achieve Equilibrium Moisture Content (EMC) with their
environment, usually resulting movement and dimensional change and
causing changes to salts.
TEMPERATURE, RH & HUMAN COMFORT
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There is often a conflict between
conservation and human comfort –
and heating buildings in cold climates
or cooling buildings artificially in hot
climates is not environmentally
sustainable.
Heating or cooling buildings can also
change the micro environment in
ways that may create conservation
dramas.
A solution can be to heat or cool the
people only, not the whole
environment.
LIGHT
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Light is a form of energy.
When a beam of light strikes a given
material, a certain amount of energy
is transferred to the surface it
contacts and several different
phenomena may occur:
- fading of colour
- degradation of material
The higher the frequency of radiation (or the shorter the wavelength) the higher the
energy of the photons – and hence the light’s capacity to induce chemical
reactions. Photons can interact with other particles (atoms and molecules).
UV is a high frequency, short wavelength, highly destructive energy.
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The term ‘light’ is used to indicate the electromagnetic radiation within the so-
called visible region – from 380nm to 780nm. However, the term ‘light’ is often
used in a broad sense to indicate all of the radiation emitted by an optical source
(UV to IR).
SOURCES OF LIGHT
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A light source is a
physical emitter of the
electromagnetic
radiation needed to
initiate visual perception.
Daylight is the most comfortable form of light for vision. It provides
uniform energy distribution over the whole visible range and offers the
best conditions for chromatic perception.
BUT it contains a considerable portion of UV as well as IR.
COLOUR TEMPERATURE
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The term ‘colour temperature’ is used to describe the quality or perceived
warmth of light. It ranges from black (coldest) through to red to blue to white (the
highest level of thermal radiation – white hot!).
Daylight varies hour by hour and day by day – and it ranges from 2,500k at
sunset to 20,000k in a clear blue sky.
DIRECT SUNLIGHT illumination can be highly damaging.
EFFECTS OF SUNLIGHT INDOORS
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Direct and reflected
sunlight can harm
indoor fabric and
contents.
For example, loss of colour may occur with light sensitive pigments. Even
reflected light can damage surfaces over time.
MEASURING (LIGHT) RADIATION
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For the conservation of light sensitive building fabric and artefacts the
parameters to be measured are; - light intensity,
- exposure, and
- ultraviolet radiation.
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The main issues indoors concern :
Corrosion (water usually exists
as vapour)
Light doses (artificial UV)
Temperature (excessive
heating and cooling)
Pollutant gases and particles
CONSERVATION
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There are not always obvious or simple
solutions for problems but there are
some reliable strategies that can be
applied to many conservation
challenges.
The following case studies illustrate
some strategies that might be applied
to other projects.
CASE STUDIES – INTERIOR WORKS
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WINDSOR HOSPITAL DEAD HOUSE
Early colonial building fabric including pit sawn timbers and hand made bricks
The object of the work was to conserve
maximum amount of authentic fabric,
using traditional methods including:
• poultice de-salination,
• lime water consolidation of brickwork,
• lime washing, and
• minimal material replacement.
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RIPPON LEA, MELBOURNE, CONSERVATORY
30 Conservatory 2010
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The conservatory at Rippon Lea, Melbourne was added to the house in the
1890s. A series of photographs of that time indicated that the ironwork had
been painted in contrasting tones. Later it was painted green.
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The condition of the iron and steelwork had deteriorated to the point whereby it
required extensive work. The ironwork was overdue for painting in 2008.
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Although it is sometimes difficult to research ironwork, due to its hardness and
corrosion, paint sampling revealed evidence of the painting history including red
oxide protective coatings, original finishes and gilding.
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The sampling was cross referenced to the photographic record of the 1890s to
confirm the nature and placement of the colours and the gilt highlights on the iron
columns.
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The materials were repaired and the colour schemes were reconstructed
accurately. This has greatly enhanced the architectural balance of the
conservatory and re-integrated it with the polychrome detailing of the complex.
ALBERT HALL, CANBERRA 1927
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Albert Hall, 2010
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Albert Hall in Canberra was opened in 1927 to serve as the new capital’s main
assembly hall – a function that has not changed greatly, although the condition
of the place has deteriorated.
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The interior of the hall had been relatively plain. It was originally painted in
oil paint in drab tones. The latest colour scheme was a ‘restoration’ in a
latex emulsion paint system.
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Conventional paint sampling revealed details of the original paint colours and
the overlying paint colour schemes.
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Various problems were encountered in the works, including substrate
inconsistencies following paint removal, colour matching and reproduction of
appropriate gloss levels with enamel paint systems.
PARRAMATTA TOWN HALL 1881
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GOVERNMENT HOUSE, SYDNEY
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Conservation of the State Rooms
1984 - 2007
ENTRANCE HALL
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DINING ROOM
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BALLROOM
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Government House
Drawing Rooms
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SUMMARISING
• Occupied places often require works to accommodate uses or
changing uses.
• Changes should be planned to avoid impacts that would affect
authenticity and significance.
• There should not be any water inside buildings to affect the
building fabric but water often exists as vapour.
• High humidity will cause decay in organic materials and will
contribute to decay in inorganic materials.
• Works inside buildings require careful attention to the
principal causes of deterioration prior to any works to restore
decorative finishes.
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