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WHY BUILDINGS DECAY
by
Dr. A. Ghafar Ahmad
Paper presented at the E & O Hotel, Penang on December 11, 1994
(Organised by the Penang Heritage Trust)
 | Introduction |
The term conservation has become familiar to almost everybody. From
newspapers to television, from small meetings to international conferences, people often
raise issues of conservation in regard to wildlife, rain forest or even historic
buildings. Conservation by definition is guardianship providing for maintenance,
preservation or protection of what presently exists, from being destroyed or changed in an
inappropriate manner. For wildlife conservation, it implies a protection of endangered
animals and plants collectively from being harmed and killed either by people directly or
by indirect human activity. In nature, there is the implication of maintaining an
ecological balance in steady state. Similarly, conservation of building requires
preservation and maintenance of buildings of the past, which have historical and
architectural significance. It is a process which leads to the prolongation of the life of
cultural property and for its utilization now and in the future.
Building conservation has long been of concern, although its popular
applications is relatively recent in origin. In Malaysia, the practice of building
conservation is considered new in the local architectural scene. In the past few years,
many historic buildings have been preserved and conserved while others have been converted
to become premises for a bank, restaurant, information centre or a printing office.
Before practising building conservation, one including an architect,
building contractor, planner or anyone who has the interest in saving an historic building
must have a broad understanding of the field itself. This is of course to ensure that any
action carried out during the conservation work is properly performed and is in accord not
only with the building requirements but is within the scope of contemporary knowledge of
the subject. The main purpose of this paper is to study the common problems of historic
buildings in Malaysia and proportion of building conditions. This includes a discussion on
building materials and their common problems or defects mainly of timber, stone, brick and
plaster.
| Present Situation of Building Conservation in Malaysia |
Before going to the technical aspects of building conservation, the
present situation of building conservation in this country should first be highlighted. As
we already know, Malaysia is one of the fortunate countries that has many historic
buildings which are of immense architectural and historical values. It is believed that
there are more than 37,000 historic buildings built between 1800 and 1948 throughout the
country which are worthy for preservation and conservation.
Like many other countries in which building conservation seems a fairly
new practice, Malaysia faces several problems in dealing with the issues of historic
buildings. First, the present legislation on historic buildings is not sufficient and
suitable to protect such buildings from being demolished and destroyed. There are
presently four Acts and Enactments which show some aspects of building conservation even
though it is felt that their application and formulation are restricted and not intended
to address the question of heritage conservation extensively. With the country's current
rapid development in which the practice of demolishing historic buildings has been the
norm, none of these pieces of legislation is comprehensive enough. Second, there is no
suitable systems for discovering and recording the historic buildings in the country. The
systems are quite important in building conservation, particularly among other things to
locate the building location, function and owner; classify the buildings into their
functions, assist the authority in keeping a record on the buildings for future research
and funding; and measure building defects and assess remedial measures. Finally, there is
lack of technical knowledge in repairing and maintaining historic buildings. This is a
major problem because almost all conservation jobs involve both repair and maintenance
stages requiring an understanding of and analysis of building defect diagnoses.
In Malaysia, under the Antiquities Act 1976 a historic building or
monument aged at least 100 years old can be listed or gazetted by the Government through
the Museum Department to give protection and encouragement for preservation and
conservation. At present, there are 51 buildings and 86 monuments which have been
gazetted. Out of these 51 gazetted buildings, only 21 buildings are British colonial
architecture. Most of them are owned by the government even though there are many
privately owned buildings which are of architectural and historical values. Example of
historic buildings in Malaysia are traditional Malay houses, mosques, churches, palaces,
clock towers, prisons, government offices, institutional and commercial, residential,
schools, railway stations, hotels and guest houses; and monuments.
| Buildings Materials and Their Common Defects |
Most of the historic buildings in Malaysia use building materials which
are easily available locally. Such building materials include timber, stone, brick and
plaster. In the care and conservation of historic buildings, understanding the nature of
the building materials and accurate diagnosis of defects is most important. This is
because historic buildings are, like older people, vulnerable to all sorts of diseases.
Therefore, in order to tackle the diseases, conservation architects, contractors,
specialised engineers and those involved in building conservation should first become
familiar with the building materials in common use before going deeper into the proper
techniques of preservation. Common building materials such as timber, stone, brick and
plaster will be discussed as well as the causes of decay in each of the materials.
Timber has long been used by man especially in building construction.
It is the most useful material available for wall, floor, roof and other structural
framing. All commercial timbers can be classified into softwoods (such as Pine, Fir and
Damar Minyak) and hardwoods (such as Chengal, Meranti and Kapur), depending on the
characteristics of their grains, weight and moisture content. In general, timbers either
of softwoods or hardwoods have a moisture content of between 12 to 15 per cent. Normally,
a well dried timber has a moisture content of 12 per cent. If the moisture content of the
wood exceeds above 20 per cent, fungal rots, insect infestation and termite attack will
eventually take place. This will further lead to structural failure. Therefore, before
timber is being used for building construction, it is important for the material to be
seasoned and preserved. The primary aim in seasoning timber (either of air or kiln
seasoning) is to render timber as stable as possible, for the timber increases its
strength properties as it dries. On the other hand, the preservation of timber, usually by
chemical processes either before manufacture or after, concentrates on fungicidal
preservation, flame-proof protection and water-repellence application.
Like timber, stone has been used in building construction for thousands
of years. Due to its natural durability and strength, stone is used for structural
columns, exterior walls, staircases, window framing as well as roofing materials. Stone
comes in different types and properties ranging from the hard impervious such as granite,
slate, marble to the softer and pervious sandstone and limestone. Although stones will
last for many hundred years, its tendency of decay in any kind of weather is possible.
Such weathering occurs in three situations. First, the attacks from soluble salts
especially when it comes up from the ground where there is no damp course, in locations
near seas or from a heavily polluted atmosphere. Second, trouble arising from the slow
build-up of soot deposits and dust, leading to possible onset of decay due to small
vegetation organisms. Third, the straight forward erosion by wind and rain. Stone will
become saturated when it is exposed excessively to driving rain. As a result, its surfaces
becomes marked and rough. Besides weathering, stone may also decay through faulty
materials and workmanship.
Another type of material used in buildings masonry is brick or burnt
clay block. Brickwork has been used in many historic buildings in Malaysia, particularly
the ones built during the British occupation. Some of the colonial buildings have exposed
brick walls and others are plastered and painted. Old bricks are slightly different than
modern bricks. The texture of modern bricks looks closer and smoother, and the edges are
straighter and sharper compared to the old materials. Colour and size are also different.
Brick may decay through weathering process including sulphurous smoke caused by polluted
atmosphere, water penetration through small holes and openings of the brick as well as
mortar joints; and dampness in wall caused by no damp course in locations near sea or
river. Brick may deteriorate due to harmful vegetation and also mould or fungal growth
that accumulate in the brick surface. Brick can also decay due to cracks caused by
structural movements. Such structural movements may come from building foundations when
subsoil is compressed through the decades or centuries followed by wall deflections due to
the foundation weakness or an uneven loading distribution from above wall structure.
Like timber, stone or brick; plaster tend to deteriorate over a period
of time. Plaster normally contains lime, sand and water; and sometimes chopped animal
hairs to give tensile strength. Plaster are used widely in decorative panels, ceiling
renderings, cornices and internal walls. Causes of deterioration include direct exposure
to driving rain, condensation, evaporation, air pollution, aerosols, capillaries, thermal
stresses, vegetal causes, insect attacks, animals and human activities. Plaster may become
cracked due to either shrinkage or movement in the substrate. Shrinkage usually occurs
early in the life of the building but substrata movement is often the reason for failure
in historic situations.
| Common Problems of Historic Buildings |
I have carried out building surveys and inspections covering site
investigations, structural survey, building condition and defects, air-conditioning
systems; and photographic study on 70 selected colonial buildings built between 1800 and
1930 throughout Peninsular Malaysia. Each building was studied externally and internally
following permission from its occupants or owners. The buildings are located in Penang,
along the west coast, in central regions, a few areas on the east coast and other remote
places; representing a geographical cross-section of colonial architecture throughout the
Peninsular Malaysia. The main purpose of the surveys and inspections is to study the
common building defects or problems and proportion of building conditions.
Of the 70 colonial buildings surveyed, 27 buildings were built between
1900 and 1920. Followed by 20 buildings built during 1880 and 1920, 11 between 1920 and
1930, 6 between 1860 and 1880, 3 during 1800 and 1820; and the other 3 between 1820 and
1860. From the survey, 18 buildings or 26% of the total buildings were in good condition.
However, the other 52 buildings or 74% shared some common building defects or problems. It
was found from the study that sometimes one building shared 3 or more common building
defects, depending on its location, age, building materials and changes in use. There are
12 common building defects or problems, which are fungal stain or harmful growth, peeling
paint, defective plastered renderings, poor installation of air-conditioning units,
defective rainwater goods, decayed floorboards, cracking of walls, erosion of mortar
joints, dampness penetration through walls, roof defects, insect or termite attack; and
unstable foundation. The most common building defects, found on 27 out of 52 buildings, is
fungal stain or harmful growth carrying 51.9%. Other common defects or problems include
erosion of mortar joints 38.4%, peeling paint 30.7%, defective plastered rendering 21.1%;
and poor installation of air-conditioning units 28.8%.
| Causes to the Common Problems: |
| Fungal Stain / Harmful Growth |
Fungal stain or mould usually occurs when there is a presence of water
or high moisture content in masonry walls. It can easily flourish in environmental
conditions of high humidity and lack of ventilation. Fungal stain can be seen on wall
surfaces of a bathroom, kitchen, near rainwater goods including down pipes and gutters;
and at washing areas.
Harmful growth including creeping and ivy plants can grow on either
stone or brick walls. This happens when dust and dirt penetrate small holes, openings and
cracks in the walls and mortar joints creating a suitable ground for any seeds to grow.
The condition becomes worse when there is water penetration through the holes. Roots can
go deep into the existing holes causing further cracks and water penetration.
| Erosion of Mortar Joints |
Basically, the main function of a mortar joint is to even out
irregularities of individual blocks, whether they be of stones or bricks. At the same time
it provides some adhesion between the blocks. Causes to the erosion of mortar joints
include a presence of salt crystallization, scouring action of winds; and disintegrating
effects of plant growing on a wall or water penetration leading to the concentrations of
moisture and dampness. Decayed mortar can be removed forcibly by the use of a mechanical
disc or carefully raked out by using a knife or spike manually.
| Peeling Paint |
Peeling paint usually occurs on building facades, mainly on plastered
walls, columns and other areas which are exposed to excessive rain and dampness. Some
buildings located near the sea may face a much greater risk once the signs of peeling
paint are visible on the exterior walls. This is because the amount of constant wind, rain
and sun received can easily turn the surfaces of the paint to be chalky and wrinkled or
blistered. In many historic buildings, there are layers of paints being applied on
plastered walls. Apart from lime wash, there are many types of paints used on wall
surfaces including emulsion, oil-based, tar, bituminous and oil-bound water paint. All of
these require different methods of removing depending on the nature and conditions of the
paints.
| Poor Installation of Air-Conditioning Units |
Most of historic buildings in Malaysia were built without
air-conditioning systems. Where buildings have to contend with high humidity and warm
temperatures, the need to install air-conditioning systems to meet modern building
requirements seems necessary. Window units and openings are usually closed and sealed to
maintain cool air inside the buildings. Depending on the building function, structures and
the effects on building fabric; one should consider four main aspects before deciding to
install the air-conditioning units in any historic buildings. Firstly, the cooler and
drier air produced by the air-conditioning systems may possibly cause shrinkage of
building materials. Secondly, there will be a possibility of condensation either on the
surfaces or within the structure of the fabric. This allows the build-up of mould or
fungal stains. Thirdly, there may be problems of installation which include difficulties
in installing the units. Finally, from the aesthetic point of view, the installations of
the air-conditioning systems in some historic buildings were unfortunately carried out in
a poor manner by simply placing the units on windows, walls or at front facade. This
affects the appearance of the buildings.
| Defective Plastered Rendering |
In many historic buildings, defective plastered rendering occurs mostly
on external walls, columns and ceiling. In a humid tropical climate, the defects of
rendering are normally caused by biological attacks arising out of penetrating rain,
evaporation, condensation, air pollution, dehydration and thermal stress. Other causes may
come from mould or harmful growth, insects, animals and traffic vibration. Prior to being
decomposed and broken apart, plastered rendering may become cracked due to either
shrinkage or movement in the substrate itself.
| Cracking of Walls / Leaning Walls |
Apart from distributing loads from roofs and floors to foundations,
external walls may be harmful to a building if they are structurally unsound. Cracks in
wall, either vertical or diagonal, are common symptoms of structural instability. Such
defects should be investigated and the cause diagnosed in either the foundations, weak
materials and joints; or any shrinkage or thermal movements such as timber window frames.
Diagonal cracks, which often being widest at the foundations and may terminate at the
corner of a building, often occur when shallow foundations are laid on shrinkable sub-soil
that is drier than normal or when there is a physical uplifting action of main roots of a
large tree close to the walls. Furthermore, there are a few causes to the problem of
leaning walls including spreading roof which forces the weight of a roof down towards the
walls, hogging and sagging due to soil movement, weak foundations due to presence of
dampness, shrinkable clay soil or decayed building materials; and disturbance of nearby
mature trees in which their roots gradually expand the local settlement.
| Defective Rainwater Goods |
Common problems associated with the defective rainwater goods include
sagging or missing eaves gutters, corroded or broken galvanized iron down pipes; or
leaking rainwater heads. Others may include undersized gutters or down pipes which cause
overflow of water, particularly in heavy rain; and an improper disposal of water at ground
level. There are a few possible causes to the defective of rainwater goods. Due to
inadequate painting, iron rainwater good can become rusted and fractured. Lack of proper
fixings of the wall, particularly by means of projecting lead ears or lugs can cause
instability to the down pipes. Where the routines of building inspections and maintenance
have been neglected, the rainwater goods can be easily exposed to all sorts of defects.
| Decayed Floorboards |
Timber floorboards are widely used in many historic buildings including
churches, schools, residential and railway stations in Malaysia. Some of the floorboards
are badly abused with serious damages on the surface and deteriorated; leading to further
structural problems and unsafety of occupants. The main causes to the deterioration are
insect and termite attacks, careless lifting of weakened boards by occupants, electricians
or plumbers; lack of natural seasoning and preservatives, and corroded nails.
| Insect or Termite Attacks |
Timber has been widely used in many historic buildings in Malaysia. It
can deteriorate easily if it is exposed to water penetration, high moisture content and
loading beyond its capacity. Insect or termite attacks are a common danger to timber.
Insect or termite attacks usually happen in a damp and digestible timber which can be
found in elements such as wall plates, the feet of rafters and bearing ends of beams and
trusses; and in all timbers which are placed against or built into damp walling. It is
dangerous to leave the timber with many insect or termite holes because they may soften
the timber and form further cracks. Affected timber can be treated by pressure-spraying
with insecticide or fumigant insecticidal processes.
| Roof Defects |
Besides being one of the main structures in a building, roof may act as
a weather shield, giving protection to users or occupants from rain and sun. Therefore, it
is important to treat any aging roof tiles. In Malaysia, clay tiles have been widely used
in the historic buildings. Common defects of roof tiles include the corrosion of nails
fixing the tiles to battens and rafters, the decay of battens; cracking of tiles which may
be caused by harmful growth or walk upon. The harmful growth is quite dangerous to the
tiles because it may lift the tiles and create leaks. Another aspect to be considered in
the common defects is the mortar applied for ridge tiles which tends to decay or flake off
over the years.
| Dampness Penetration Through Walls |
Dampness penetration through walls can be a serious matter,
particularly to the buildings which are located close to water sources. It can cause not
only deterioration to the building structures but damages to furnishings and contents as
well. The main cause of dampness is water which may enter a building by a number of
different routes. Water penetration occurs commonly through walls exposed to prevailing
wet wind or rain. With the existence of gravity, water is likely to
penetrate through capillaries or cracks between mortar joints and bricks or blocks before
building up trap moisture behind hard renders and also driving further up the wall to
emerge at a higher level. Dampness may also occur in walls because of other factors such
as leaking gutters or down pipes, defective drains, burst plumbing and condensation due to
inadequate ventilation. Dampness may also enter a building from the ground through cracks
or mortar joints in the foundation walls.
| Unstable Foundations |
Foundations are a part of a building which distributes loads from
roofs, walls and floors on to the earth below. They are structurally important to the
permanence of a building and if this is lacking there is no point of spending large sums
of money on other superficial restoration work. Most of the common problems occured in the
foundations depend on the geology of the ground upon which a building stands and is
surrounded by, structural failures; and presence and height of a water table. Besides,
inherent failures may also happen in a building in which it has to cope and carry any
unsettled problems of the foundations. A famous example is the Leaning Tower of Pisa in
Italy of which inherent failures caused by corrections made during construction combined
with traffic vibrations, deep construction and abstraction of water from deeper layers of
soil have led to its present leaning position. It is important to understand that all of
the common problems of the foundations may lead to unstability of the building structures,
causing unsafety to users or occupants. Unstable foundations may occur because of several
reasons including shrinking clay soil, resulting when the sub-soil is drying and water
table is low which no longer holds the structure above; penetration of dampness and water
that may decay walls and foundations; presence of large trees near the building; and the
undertaking of extensive excavations or mining nearby. Other cause include landslides
caused by heavy rain, heavy construction near an historic building and lowering of water
tables, usually by hard landscaping and road areas. Unstable foundations may also occur
from traffic vibrations, deteriorating of building materials and the increased loads,
particularly when there are changes in building function.
| Factors That Govern Building Defects or Problems: |
There are 5 factors that govern building defects or problems.
| Climatic Conditions |
It is important to consider the climatic conditions of Malaysia and the
effect on building materials. Like many other tropical countries, Malaysia has heavy
rainfall and warm sunshine all year round. This implies that buildings in the country tend
to weather rapidly, particularly in respect to external building materials which are
exposed to external causes such as rain, wind, solar radiation including ultra-violet
light; and atmospheric pollution. Fungal stain, harmful growth, peeling paint, erosion of
mortar joints and defective plastered rendering are a few examples associated with this
factor.
| Location of Building |
Buildings that are located near the sea or rivers tend to have common
building defects. This is because the water coming from the ground causes dampness
penetration and structural instability. For example, during the conservation work of the
Sultan Abdul Samad Building in Kuala Lumpur, damp-proof courses had to be installed in
order to prevent rising water coming from nearby Gombak River. In addition, soluble salt
which comes from sea and together with the presence of a polluted atmosphere can cause
damage to the exterior surface of the buildings.
| Building Type and Change in Use |
Most historic buildings that maintain their original functions or uses
appear to have less problem internally, even though there were symptoms of building
defects found on the external fabric. Buildings that change their use and spaces should
consider the effect of the new use on the existing structure. This is because historic
buildings were built to only hold certain loads and sometimes may not withstand additional
loads. Where buildings which have been converted into either commercial or office
purposes, the need to install air-conditioning systems to meet modern building
requirements seems necessary. It has been found that in a few cases the air-conditioning
units were placed improperly. This not only affects the appearance of the buildings but
intervenes with the existing fabric, particularly when ducts are running in full view on
the ceiling.
| Maintenance of Building |
Building maintenance organized through a rigorous programme of cyclical
maintenance plays a major role in preventing building defects. Historic buildings that
neglect building maintenance may fall into several defects which may lead to structural
failures. Any inspections carried out by either architects or surveyors should include
checking for any signs of abnormal deterioration, cleaning out gutters of leaves or
harmful growth, checking lighting conductors, cleaning out all voids and spaces; and
changing tap washers. To secure the general structural stability and life of a building,
it is important to regularly inspect not only the main structural elements including
foundations, walls and roofs; but other common building problems.
| Building Age |
All elements of historic buildings tend to deteriorate at a lesser or
greater rate depending upon their location and function. Aging building materials,
particularly timber should be checked once there are signs of fungal and termite attacks.
Building that were built in the early period of British occupation, for instance, often
face problems in building materials. Therefore, proper treatment of building repair and
maintenance should be given full consideration.
| Conclusions |
Identifying common building problems and understanding of building
materials explained in this presentation are considered as part of the process of
preserving and conserving historic buildings. Reasons for building conservation, adopting
proven techniques and treatments, maintaining the historical and architectural values are
a few examples of areas that one should have a knowledge of before practising building
conservation. As a conservation architect, engineer, surveyor, historian, planner or
anyone who has the interest in saving our architectural heritage, we have to make sure
that our historic buildings are handed to the next generation in good conditions.