1. Introduction

It is only recently that heritage buildings in Malaysia have taken stage in the limelight.  Most heritage buildings are generally susceptible to deterioration, partly due to factors such as poor maintenance and improper restoration methods.  Many heritage buildings are inevitably ageing and share common problems of leakage, dampness, termite attacks, etc. Restoration of Old City Hall in Georgetown, Penang portrays an important milestone towards retaining and conserving Malaysia’s invaluable heritage buildings, as these structures are reminiscence of an intriguing past (see Photo 1). Moreover, from an economic viewpoint, heritage buildings are lucrative assets in promoting tourism, especially in Penang.

This paper discusses details of the restoration works of the Old City Hall, a heritage building located along Jalan Padang Kota Lama, on Lot number 69, Section 19, Georgetown, Northeast District of Penang, Malaysia. On 29 July 1982 the Old City Hall, renowned for its significant historical and architectural values was gazetted as a national monument under the Antiquities Act 1976 (gazette no. PU (A) 221).

The Federal Government has allocated some RM3.58million for the restoration project. Interestingly, the project has adopted a conservation approach that combined the principles of restoration and refurbishment. Conducted in two stages during April 2004 to April 2005, Stage One of the project involved the restoration of building structures and elements, salt desalination and termite treatment. While Stage Two included the interior refurbishment of the Council Chamber, main lobby, councilors’ offices, mezzanine floor, dining hall and toilets. The scope of work undertaken included restoration and repair works; mechanical and electrical services; as well as landscaping.

Photo 1: Old City Hall before restoration and refurbishment

2. HISTORICAL AND ARCHITECTURAL SIGNIFICANCE OF PENANG CITY HALL

The Old City Hall built in 1903 was typical of the British Palladian architecture, a contemporary style established during the British colonial era. The design of Old City Hall bears a resemblance to the nearby Old Town Hall, which features the balcony as a main element overlooking the esplanade. Old City Hall is currently used by the Penang Municipal Council (MPPP) to house two of its supporting offices, namely the Licensing and Urban Services Departments. Other MPPP departments, which were once sited in this building, have since moved to KOMTAR, a 57-storey office tower block located in the inner city of Georgetown. The Old City Hall is also the venue for the Council Chamber’s monthly meetings, various gatherings and functions.

In the initial stage, MPPP had intended to restore only the Council Chamber, which is located on the ground floor of the North Wing. However, results from the dilapidation survey had revealed the nature and extent of the building problems, mainly rising damp, salt contamination and termite infestation. Following an in-depth investigation, it was decided that preserving a portion of the building was impractical and futile as the problems of dilapidation would recur and persist

3. BUILDING DEFECTS

Measured drawing works of Old Town Hall were commissioned in 2002 for a duration of two months. A Penang City Council renovation plan prepared in 1973 and an original front elevation drawing were both used as the base plan for this exercise. The main objectives of preparing the measured drawings were to obtain the latest information on the renovation works of the existing building, and to understand the extent of modifications rendered onto the building.  The measured drawings were able to show not only the additions to the building interiors, but also changes made on the structures and facades.  It also indicated the various building materials used and their status, be it original or new additions, and other relevant information such as the location of door and window openings. Based on the measured drawings, a thorough survey of the building was conducted with greater precision. However, it was found that most of the previous renovation works had been conducted without proper documentations and drawings. This situation has, to a certain extent, affected the task of diagnosing the building problems.

There were four main phases in identifying problems associated with the Old City Hall building:

Phase 1:Reconnaissance Survey

The reconnaissance survey involved a general investigation of the building interior and exterior to gauge the nature and extent of the building problems, and to identify the panels to be removed for subsequent treatment.  The building plan was categorised into grid zones for purposes of systematic documentation.

Phase 2: Pictorial Documentation

The pictorial documentation entailed capturing in digital format the entire building structure based on the specified grid zones, with an emphasis on the dilapidated areas.

Phase 3: Detailed Investigation

The detailed investigation phase involved the removal of dilapidated panels from the affected grid zones. The removal process was captured digitally to document the condition of the building façade before, during and after the removal procedures.  Several panels had to be removed to make way for difficult and far-reached areas, such as the ceiling voids.

Phase 4: Dilapidation Survey

The final phase involved the preparation of a dilapidation survey based on related data collection and analysis. A dilapidation survey is essentially the practice of identifying and recording building defects through photographic and digital documentation prior to any restoration work (Ahmad, A.G, 2004). In this phase, the dilapidation survey was produced to assist in the designing process as well as for preparation of the tender document.

Similar to many heritage buildings in the country, the Old City Hall is a two-storey masonry building featuring several building elements made from timber. Most of the materials on the first floor of Old City Hall were made from timber such as ceilings, floorboards and openings (timber frames). However, the beam supporting the first floor was of steel I-beam.  Some of the walls were clad with panels using brickwork, gypsum board, and composite materials to create new walls. Some of the arches were enclosed by brickwork or plywood, in order to create new enclosures.

Findings from the dilapidation survey have confirmed the generally poor condition of the building. Building diagnoses showed numerous problems of signs of leakage, watermarks, termite infestations, rising damp, salt contamination, organic growth and water seepage. During the detailed investigation phase, the removal of the panels had further discovered similar problems affecting the structures behind the panels as shown in Photos 2 and 3. Consequently, an extensive restoration work was proposed for the Old City Hall in order to rectify the serious building defects.

Photo 2: Termite Infestation to the Ceiling Joist

Photo 3: Dampness Problem

 Other building features were also surveyed including furniture, lightings, plywood for wall panels and floor finishes.  Some of these elements including plaster works and floor finishes were seriously decayed. Some of the timber flooring finishes, for example, needed to be replaced while the tessellated floor tiles were in need of restoration.

The building problems encountered at the Old City Hall can be summarized as follows:

1.        Ceiling – Some timber ceiling were rotting due to water leakage and condensation from the air-conditioning ducts.  Some of the new ceilings were affected by termite attacks and sporting unsightly watermarks.

2.        Walls and columns – Some masonry walls and columns were affected by rising damp, which led to the problems of crumbling plasterworks on the columns. Cement plasters were found on walls and columns from previous repair works. The walls and columns were experiencing cracks, peeling paints and organic growth. Newer walls, which were built of boards and timber studs were also experiencing termite attacks.

3.        Flooring – The floor finishes underneath the carpet were of mosaics and timber, but most of the floor areas were of cement render.  There were some floor areas of cement tiles including the areas from the staircase lobby to the mezzanine floor. The timber floorboards were facing problems of wood rot and termite attacks.

4.        Staircase – The condition of the main staircase to the first floor was generally fair. However, the rubber strips on the threads were not properly secured. Some of the balustrades were of a different design, which may be related to previous replacement exercises. It was suggested that the staircases be restored to their original design and colour.

5.        Timber structures – Timber structures including floor joists, ceiling joists and floorboards were all in a varied condition. Some of them had needed replacement while others had required repair works.

6.        Rising damp – Since the Old City Hall is located close to the sea (about 50 metres away), it is a natural occurrence that the building experiences severe problems of rising damp. Rising damp were detected on all plastered wall surfaces, covering an area as high as between 5 to 7 feet above the ground. In some areas, it had affected both the ground floor and the first floor of the building.

7.        Salt contamination – All inspected walls of the building showed high levels of salt contamination as well as rising damp. The presence of white salt deposits including Nitrate (NO3) and Sulphate (SO4) had resulted in crumbled plaster walls and attributed to the porosity of the brickworks.

8.        Termite problem – The building was in a poor state due to serious termite attacks, which had occurred as a result of dampness problems and lack of maintenance.

9.        Poor rainwater goods – Several rainwater down pipes were in a poor state. Some ran inside the building, which posed a threat of leakage. A down pipe located close to a switchboard could cause electrocution, if the pipe leaked.

4. HISTORICAL ARCHITECTURAL BUILDING SURVEY (HABS)

Recognised as a requirement by the Department of Museum and Antiquity Malaysia, a methodological system of recording the building conditions before, during and after restoration and refurbishment was practiced at the Old City Hall. All walls, windows and doors of the building were fixed with yellow strings to form small grids of 1m². Each grid was then coded systematically, photographed and stored in a computer database. All information on the building conditions, conservation techniques, grid locations and photographs were recorded in a standardised and systematic format before they were stored in a database for future references and final documentation.

5. SCIENTIFIC STUDIES

The project required in-depth knowledge and expertise on building structures and materials as well as its defects and causes. In order to identify and subsequently solve the building defects, scientific studies and laboratory tests were carried out to discover the best ways to tackle the problems using the appropriate techniques, methods and materials available. The scientific studies conducted included timber species and strength group, paint colour scheme and tessellated floor tiles.

5.1 Timber Species and Strength Group

Officers from the Malaysian Timber Industry Board (MTIB) were invited to carry out the verification of timber species and strength groups of timber structures and elements of the City Hall on 5th July 2004. The main objective was to confirm the different types of timber used in the building. Such information was crucial in the restoration works, particularly when replacing old timber structures and elements with new ones. It is important to ensure that the new timber installed is of the same species and of similar strengths. Samples were taken from various timber structures and elements on the ground floor including window frames and panels, floorboards, joists and wall panels. All timber samples were coded and labelled accordingly for future references.

The MTIB results found that 2 types of timber species were used at the ground floor of the City Hall building. The Red Meranti (Shorea spp) timber was used mainly for the window frames and flooring on the ground floor. The newly added wall panels that were installed during the previous renovation also used the same timber species. Nyatoh (Sapotaceae spp) timber of strength group C was widely used for the newer windows. A summary of the timber species and strength groups is shown in Table 1.

Table 1: Timber Species and Strength Group

Based on the results issued by the MTIB as well as from site inspections, Red Meranti (Shorea spp) timber was found most widely used on the ground floor of the Old City Hall followed by Nyatoh (Sapotaceae spp) timber. During the restoration works, the same species of timber (seasoned and treated) was used to replace any rotting flooring, window frames and panels.

5.2 Paint Colour

Identification of the original building colours entailed the use of new paintworks including colour and type of paint. In the restoration of the Old City Hall, paint scrapping of several building elements including external and internal walls, columns, pilasters, window and door mouldings, staircases and windows was considered vital in tracing the original colours of the building. Paint scrapping was undertaken internally at 10 locations.  Each paint scrapping was carried out 1 meter above the floor level. Using a small fraction of sand paper, each layer of paint was scrapped off in a circular motion, starting with a bigger circle for the first layer of at least 300 mm in diameter followed by smaller circles inwards for the rest of the layers. Each exposed paint layer was then marked in numbers and photographed for future references.

Results revealed that some of the locations identified for paint scrapping were covered under many layers of paint. The walls on the ground floor, for instance had 3 layers of paint. The window, door moulding and the walls on the first floor were also painted in 3 layers. Several walls and columns on the first floor were painted at least 4 times in different colours. Most of the walls and mouldings were painted in yellow, cream, white and light blue. Results of the paint colour scheme had provided evidence to verify the original building colours and the type of paint used.  Cream was chosen as the main colour of the interiors.

5.3 Tessellated Floor Tiles

In Malaysia, tessellated floor tiles have been widely used in buildings built in the late 19th century. Such tiles are commonly found in old buildings including government offices, railway stations, mansions, terrace and shop houses. The tessellated tiles, which come in different shapes, sizes and colours, can be found on the ground floor at the entrance, lobby, lounge or five-foot way (corridor). Each tile is laid accordingly to form interesting geometrical patterns. In Georgetown, tessellated floor tiles can be seen in several British colonial buildings including the Old City Hall, Old Town Hall, High Court and Governor’s Residence.

A thorough investigation was carried out to record and document the tessellated floor tiles found at various locations in the building. The tessellated floor tiles, which are of red, maroon, black or yellow in colour, were carefully laid to form standard geometrical patterns including the inner checkers and border frames. A total of 14 types of tessellated floor tiles were found at the main entrance lobby of the Old City Hall. Each type was unique with different shapes and measurements as shown in Table 2. Information of the tile sizes was later used as references for any replacement or repair of the old tiles.

6. LABORATORY TESTS

Apart from the scientific studies, three laboratory tests were also carried out on the building materials to identify the level of salt content, the component elements of building materials and the compressive strength of the new wall plaster. For the salt content and building materials, several samples from the building were secured for laboratory tests off-site. Testing of the compressive strength of the new wall plaster was carried out on site using the Schmidt hammer rebound test.  Schmidt hammer rebound test is used to determine the strength of the plaster by applying very high force on the plaster.

6.1 Level of Salt Content and extent of Rising Damp

Salt attack is one of the most common problems faced in the process of conserving heritage buildings.  It is sometimes called salt damp.  It refers to damage in buildings commonly caused by the destructive action of moisture and salts. It can be obviously detected by the presence of salt, seen as a white efflorescence or flowering on the wall surface (City of Adelaide, Department of Environment and Natural Resources, 1997). Other signs of salt attack include telltale signs, such as spalling of the surface and fractured materials when through to the destruction of the internal structure of the masonry (http://www.saltdamp.com.au).

Table 2: Type of Tessellated Tiles

Pattern A                               Pattern B

Salt attack is mainly related to rising damp. Buildings of the colonial era (especially 19th century buildings) are highly susceptible to salt attack because they have no Damp Proof Course (DPC). The absence of DPC will allow moisture from the ground to soak upward (capillary action). This moisture will dissolve the soluble salt from the building material itself and will also carry soluble salt from the ground (from soils and groundwater), thus causing damage to the building (City of Adelaide, Department of Environment and Natural Resources, 1997; Freemantle, 2000; http://www.buildingconservation.com).  The moisture will eventually evaporate but salts cannot, therefore salt residues are left behind on the wall.

There are two types of salt attack depending on whereabouts the salt penetrates. One is when the salt penetrates on the surface that will be shown as powder, while the one penetrating below the surface is more serious as salt will be crystallised.  The growth pressure from the crystallisation process will cause building materials to blister and crumble, thus causing serious damage to the buildings.

There are different types of salts that can cause damage to the building masonry, such as sodium chloride and calcium sulphate, carbonates, chlorides, nitrates and sulphates of calcium, magnesium, potassium and sodium.  Other problematic salts include sodium sulphate and magnesium chloride (City of Adelaide, Department of Environment and Natural Resources, 1997).

Other causes of salt attack include:

·          Windborne salt spray, if the building is near the sea,

·          Airborne salt (meteoric)

·          Pollution from nearby factories,

·          Biological, for example bird droppings, fallen leaves in block gutters, sewer leakage

·          Brick clay puddling

·          Unsuitable chemical for cleaning

(City of Adelaide, Department of Environment and Natural Resources, 1997).

The ground-floor walls of the Old City Hall were observed and analysed after some of the panels and temporary partitions were removed. It was found that all inspected walls had high level of salt contamination as well as rising damp. The presence of white salt deposits including the Nitrate (NO3) and Sulphate (SO4) had not only caused crumbled plaster walls but also attributed to the porosity of bricks (as certain bricks become soft and powdery).  As the rising damp occurred at the lower level of ground-floor walls, where the salt contamination was spotted, it is important to highlight that these problems were considered serious cases and that they could affect the strength of the existing load-bearing walls. Both salt contamination and rising damp related problems were resolved and tackled by the experts to ensure the quality of the restoration works

6.2 Components of Building Materials

Identifying the actual compositions or rather, the closest possible proportions of existing building materials including mortar joints, plasterwork on walls and ornamental elements (balustrades at parapet) through the X-Ray Fluorescence (XRF) tests was crucial in the restoration works of the Old City Hall. Any new mixtures of plasterwork and concrete should be well blended or harmonised with the existing materials of the same nature. The main objective of the XRF tests was to analyse and identify the composition of building materials that made up the mixtures of the mortar joints, plasterwork and ornamental elements of the Old City Hall. Such information was essential in the conservation and restoration works, particularly when repairing, replacing or re-plastering the existing building materials. Results from the XRF tests were analyzed before any new mixture was prepared on site for the process of trial match on mortar joints, walls or ornamental elements.

Some 6 (mortar joints and internal wall plaster) samples of existing building materials from the Old City Hall were sent to the Universiti Sains Malaysia Engineering campus at Nibong Tebal, Penang for the XRF analyses.  The XRF results noted that all samples had the highest percentage of Silicon Dioxide (SiO₂) followed by Lost of Ignition (LOI) and Calcium Oxide (CaO). Even though water, sand and lime were the 3 major compositions of the samples tested, the XRF tests also revealed that black cement (Al₂O₃), in a relatively small percentage, were also present in all samples.  The presence of black cement in all samples may be partly due to the repair works that were carried out over the years as well as the bonding agent. However, the use of black cement was not recommended in the new mixture as it was not considered to be the original composition.

In addition, there were other elements found in the samples including Sodium Oxide (Na₂0), Magnesium Oxide (MgO), Potassium Oxide (K₂O), Mangenese Oxide (MnO) and Titanium Oxide (Ti₂O). The XRF tests did not detect the types of sand or lime used in the original mixtures. However, the composition of water, sand and lime found in the samples provided a sound basis for the proportion for the new mixtures.

6.3 Schmidt Hammer Rebound Test on New Wall Plaster

During the restoration of the Old City Hall, the process of trial match on mortar joints, walls and ornamental elements were conducted to ensure the suitability and quality of the new mixtures. Based on the results of the XRF tests, several possible mixtures of slightly different proportions were prepared for testing. Specifically, a mock up of 6 wall plaster samples were set up to gauge the suitability of the selected proportion of new mixtures under normal weather condition. The plaster samples were left to dry for a period of at least 2 weeks. Information regarding the proportion and composition of the new mixtures were recorded for future reference. If fine cracks appeared on any of the new mixtures after several days of exposure, such proportion would be disregarded.

Three types of lime were available in the market including quick lime (Calcium Oxide), putty lime and bag lime. The quick lime or lump lime was used to prepare the new wall plaster because it made long lasting and top-quality lime wash for both external and internal use. For best results, the quick lime was soaked in warm water for at least 2 weeks to allow all bubbling and trapped air inside the lime to cease. Since lime and sand were used for mortar joint and wall plasterwork at the Old City Hall, their good mixed texture was based on the quality of lime putty and the grading of sand aggregates. Fine or filtered sand aggregates are the best type of sand to be used for any lime-sand mixtures. This would guarantee the smoothness effect, particularly on the wall plaster. Depending on the local weather conditions, an equal proportion of lime and sand can be used in the mixtures. At other times, a ratio of 2 parts of lime putty to 1 part of sand seems more acceptable. Getting the right proportion of composition elements was important in preparing the new mixtures. Nonetheless, all mixtures need to be tested in the trial match prior to any re-plastering.

Six sample panels of lime plaster were tested on site for their compressive strength through the Schmidt hammer rebound tests. The sample panels, comprising different mixture ratios of sand, lime, water and brick dust, were plastered onto the exterior walls for a period of 3 weeks prior to the Schmidt hammer rebound tests. Each sample panel had undergone 8 rounds of the Schmidt hammer rebound tests at 8 different points on the plaster surfaces. In addition to the 6 new sample panels, 2 existing plaster walls at ground and first floor had also undergone the Schmidt hammer rebound tests. The main reason for testing the existing plaster walls was to compare the compressive strengths between the new and the old plaster walls. Results of the existing plaster walls showed relatively higher scores compared to those of the new sample panels.

This was due to the fact that the existing plaster walls had been re-plastered and repainted several times and had hardened over a long period of time. Results from the Schmidt Hammer rebound tests concluded that all 6 new sample panels had similar compressive strength. However, the choice of selecting the appropriate sample mixture proportion for the re-plastering works depends on other factors including smoothness, texture and crack resilient.

7. REFURBISHMENT

The idea of refurbishing some parts of the Old City Hall was first discussed during one of the Council meetings in view of the poor conditions of the buildings, ageing finishes and the level of noise transmitted into the Chamber. Thus, in Stage Two of the project, the interior of the Council Chamber, main lobby, councilors’ offices, mezzanine floor, dining hall and toilets were refurbished. This had posed a challenge to the consultants in retaining the authentic building structures and fabric whilst fulfilling the functional requirements of an office environment at the Old City Hall. The concepts of restoration and refurbishment were adopted to enhance the architectural significant of this colonial building. Temporary wall panels were removed from the buildings to retain the originality of the interior. Carpets were removed to expose the original timber floorboards. New tessellated tiles were used as the floor finishes for the main lobby and the main circulation to match the original design and colour.

To satisfy the functional requirements of a modern office atmosphere at the Old City Hall, the Council Chamber was equipped with the state-of-the-art conferencing system including audio visual, computer, internet networking and LCD projector. All rooms were installed with new lighting fixtures and air-conditioning units. Suitable furniture including sofas, tables and chairs were carefully selected to suit the unique architectural style and building ambiance. As the building required a main dining hall to hold certain functions, a room on the ground floor was restored and refurbished for this purpose. The mezzanine level that was added on to the room was later removed to reveal the original ceiling height (see Photos 4 and 5).

Photo 4: Image of the Main Dining Hall before refurbishment

Photo 5: Image of the Main Dining Hall after refurbishment

8. CONCLUSIONS

The restoration and refurbishment of the Old City Hall had posed another great challenge to those directly involved in the conservation of this historical landmark of Penang. Conducting structural investigations and diagnosing building conditions during the dilapidation survey had required not only inputs from the professionals but also other specialists and experts to ensure that the entire building was restored accordingly. The client’s requirements that included the interior refurbishment of the Council Chamber, main lobby, councilors’ offices, mezzanine floor, dining hall and toilets were carefully carried out with minimum disturbance to the existing structures. It is noteworthy that the combined concepts of restoration and refurbishment have been successfully adopted in the Old City Hall restoration project. It is evident that this approach is viable in retaining the authentic building structures and fabric whilst satisfying the functional requirements of an office setting at the Old City Hall.

ACKNOWLEDGEMENT

The authors would like to thank the main contractor, Pembinaan Bertegas Makbul Sdn. Bhd.; and the salt desalination specialist, Westox Building Products (M) Sdn. Bhd. for providing information and test results of timber structures, the XRF analyses; and level of salt contents.

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