Singapore's Fullerton Building is among the grandest of the old colonial buildings in South East Asia. In the 1930s, under British rule, it was the principal General Post Office for the region, looking the part with its Corinthian columns and 'stone' finish. Its three upper storeys housed the Singapore Club where the ruling elite danced and gossiped.
Soon the visiting business elite may do the same, when the building becomes a five star hotel boasting the premier location in the city, on the bay at the mouth of the Singapore river. But the building will retain the look that features in all the skyline photographs. The Fullerton is being restored.
Though only completed in 1928, the building's local significance is comparable with London's Somerset House. But it has gently decayed while a new independent Singapore grew up around it, determined to forget pre-war colonial status in a high-rise air-conditioned future.
But gradually the city has re-evaluated its history and is anxious to retain what remains.
'Fullerton is being restored on a much more authentic scale than buildings have been done here in the past, ' says Mike West, a specialist from consultant Oscar Faber. As had been normal practice in Europe and North America, Singapore had previously considered restoration to be retention of a facade, with a complete rebuild behind. But recently, opinion worldwide has began to swing in favour of keeping more of old structures. Regulations in Europe often insist on retaining the original structure.
Singapore has not yet gone so far down that road, West says, but it is now more concerned with preservation. A substantial part of the Fullerton is to be kept. 'Unless you do that, ' says West, 'you really do not retain the character of the building - it can become relatively lifeless.'
West has already been involved with renovation studies on the Supreme Court building, City Hall and the Cathedral for the Singapore government.
The dramatic change of use from office to hotel does mean compromise, says West. But he has helped convince the city-state to minimise alterations.
His task then, as designer for client Precious Treasure, part of Hong Kong based Sino-Land, is to put everything required for a super class hotel - sometimes called a 'five and a half star' hotel - into the old building. The answer has meant false floors, M&E hidden in existing building spaces, compromise with the sometimes inflexible requirements of modern hotels, and lots of analysis.
Oscar Faber has also been retained by the French design build contractor Dragages et Travaux Publics on detailed implementation of the design requirements. Dragages was awarded the S$168M ($96M) contract and is winning praise all round for its skills on the project.
Biggest task both in design and construction has proved to be renovating and upgrading foundations for new loads. The triangular shaped Fullerton, built around an internal courtyard and wedged between the original seafront, the Singapore river and a main street, was founded on an outcrop of relatively solid ground in the normal marine clay mud.
'This is called bouldery-clay, ' explains Faber's local firm director Lee Tuck Cheong, 'which is literally that; a hard silty to sandy clay with sandstone boulders.'
Fullerton sits almost exactly over the outcrop and the original designers created a giant raft for the heavy building.
'This was a cellular structure in reinforced concrete, 1.65m deep - quite lightweight and rigid, ' says Lee.
Settlement has been minimal, but this was almost by chance, says West.
The raft is flooded, which means it has cracked and detailed examination has revealed it was too lightly reinforced.
'But the ground below is possibly a lot stronger than the designers allowed for, ' he adds. Faber worked with local geotechnical specialists, taking cores to make an accurate assessment of ground strength.
The raft has functioned for 70 years, so the best restoration solution was to retain it, says West. The top was removed from some of the cells and a detailed map produced, starting with data from an earlier radar survey. The concrete was assessed for carbonation, chloride attack, and sulfate attack.
'There was spalling, ' says Lee. 'The groundwater is direct from the sea and fairly aggressive. A lot had to be hacked out and repaired' Loads were calculated taking into account the proposed changes to the building. In particular the hotel will need lifts, and that means lift pits. In these locations cells were infilled to form reinforced concrete slabs.
Elsewhere new column loads were to be imposed. In these locations the raft was strengthened with additional reinforcement, usually by coring through the cell walls to put in steel.
But there will be no attempt to make the raft watertight. 'It would be impossible, ' says West. Even dewatering for the contractor's work was limited to the immediate area of operations to avoid adverse effects on the groundwater regime.
Wa t e r t i g h t n e s s w i l l i n s t e a d b e ensured by creating a drainage cavity layer above the raft, equipped with sump pumps. Above that will go a watertight membrane.
Above the raft interior changes were needed. The government planners accepted removal of three buildings in the interior courtyard to allow addition of extra depth to the building's three main triangular sides.
The layout is changed, says Lee. What were sorting areas and in later use, offices have been transformed into guest rooms and corridors. Load patterns change with insertion of interior partitions which 'must be reasonably heavy for acoustic reasons', he explains.
'But, ' emphasises West, 'we have kept the building structure back from the facade for one whole bay.' Load changes on main beams and columns has meant strengthening, cutting away the concrete and adding reinforcement, cast in with new concrete.
'Where possible this has been avoided, ' says West. Load tests on secondary beams, for example, demonstrated that they could take the newer loads.
A further difficulty emerged with the need to fit in extra floors to make the hotel economically viable.
Working with Architect 61, which is creating the hotel, Faber has added false floors to the front bays of the older zone which then match floor levels in the new inner structure where an extra floor has been inserted.
Spaces under these 'over-floors' provide solutions for the M&E, says West.
Air conditioning is vital for a five starhotel, he adds, despite some possible secret hankering for older, natural circulation solutions.
But in South East Asia, contractors are not used to working with ducting other than in straightforward ceiling positions, he says, so this took some discussion. Another major factor was the decision to use a basement floor cavity, installed by the original designers for air circulation. This has grilled openings at ground level which proved highly suitable for air-conditioning intake, instead of the usual outside towers. But it meant running the ducting in unusual places.
Another compromise with modern design concerned the ballroom addition. This sits below ground level at the front of the building inside an up to 25m deep secant pile wall.
The usual arrangement of putting ante-rooms at the same level as the ballroom would have meant cutting into the raft, explains West, and costing came up with a figure of millions. Instead the ante-rooms will have steps down to the ballroom.
A second dance room will be created on the fourth floor in the former Regency Room of the Singapore Club, whose vaulted roof is now the subject of a preservation order. The room was originally supported on columns in the open courtyard, and the space below it is now a glazed and air-conditioned atrium.
An extra storey has been added to the upper level of the old building to house plant. But West thinks the addition will not intrude on the building line. The new level will remain within the visual envelope of the Fullerton's 'classical' lower two storeys and upper three storeys with a red tiled roof.
Tiles will be restored, replacing redcoloured profiled aluminium cladding installed 10 years ago in a first renovation of the then Inland Revenue building. Considerable trouble has been taken to repair and match the original.
Externally, the building is clad in reinforced concrete blocks cast to look like Aberdeen Granite and panels of heavily worked and trowelled 'Shanghai Plaster', ground and polished to look like stone. Both work very well, says We s t .
Contractor Dragages has gone to some length to locate aggregate to match the colour of panels where they need repair. 'We had to experiment with aggregates to get it right, ' says contract manager Keven Page.
Across the road from the Fullerton, on reclaimed land where once there was seafront, sit two other sections to the project. First is One Fullerton, a two storey retail and restaurant complex with a ship-like roof shape and a roof garden, developed as part of the planning agreement with the owner.
Below the seafront building is a three level basement for parking, which was built within a 30m deep diaphragm wall using top down construction. The ground here is not firm but the soft marine clay found in many part of the city.
The basement parking is connected to the Fullerton by a concrete box tunnel supported on piles. A major requirement was to make this box robust enough to act as a bridge for 30m of its 40m length because it passes over the top of a future MRT mass transit line.