The restored Howrah Town Hall with its barrel roof and red brick walls. Picture by Anup Bhattacharya

At a time when heritage and conservation experts in the city are splitting hairs over how to repair and restore the 300-year-old Writers’ Buildings, another 129-year-old heritage structure, the Howrah Town Hall, has been repaired, renovated and made open to public after nearly a decade since it came crashing down on December 4, 2004, at a cost of Rs 1.06 crore

For the engineers engaged in the restoration of the Howrah Town Hall, the challenge was to restore 129-year old structure without changing the look and character of the building. They have done their task by using modern technology and materials.

Experts at Bengal Engineering and Science University (Besu), overseeing the restoration project, advised agencies entrusted with the task, to use new age materials, particularly while restoring the barrel roof of the building. “Using modern technology and materials while restoring heritage structures is very much part of heritage conservation,” said Saibal Ghosh, professor at Besu, associated with the restoration work. However, it is pertinent to note that parts of the roof, walls and verandas of the town hall were restored by using the same materials that were used 130 years ago.

CalTech, the firm that was originally appointed to restore the building, restored the verandas using lime and surki (finely powdered burnt clay) and baked terracotta tiles that rested on wooden kari and barga (beams). A solution made of surki, gur (jaggery), methi (fenugreek) and bel (quince) was injected deep inside the roof to consolidate the lime and surki layers through small nozzles. The old and damaged wooden kari and barga were also replaced.

However, CalTech left the work after 2010. Sources said they were replaced because the restoration process was taking too long and expenditure was rising. In came another firm, DP Kumar, in 2011 but it left the same year. Finally, Nibedita Constructions finished the job.

Defending the use of concrete cement in the restoration of a 130-year-old lime and surki building, Ghosh said: “The technology used in building the arched roof 130 years ago is now obsolete and the materials used are no longer available these days.” The engineers said that the barrel roof of the town hall was originally built by placing several bow girders that rested on a 25 inch wall. Numerous small iron girders were placed on the bow girder and these were covered with terracotta tiles. A thick layer of lime and surki were applied both on the roof and ceiling of the building. “The lime and surki used in building the town hall 130 years ago, are no longer available now. The quality of such materials is much inferior. If we used them, seepage would start within a few years. Besides, the terracotta tiles are not available anymore. So we used ready mixed cement (RMC) concrete in place of lime and surki,” said Mrinmoy Chandra, Engineering Overseer of Building (EOB), Howrah Municipal Corporation (HMC).

Engineers of Nibedita Construction first laid a 25 inch wide and 30 inch thick concrete beam on top of the wall for the bow girders to rest on. The bow girders were then covered with pieces of iron sheets with spikes jutting out from them. A net using iron rods was laid on the spikes and a four inch thick layer of RMC concrete was applied on it. “However good the quality of lime and surki, after a certain period of time, water starts seeping through the layers, it percolates through the tiles and develops leakage,” said an HMC engineer.

“The new technology used for restoring the roof has made it at least 60 per cent lighter than the old one. The purpose was to make the structure durable and strong without changing its original shape and character,” he added.

Earlier, the layer of lime and surki was applied even on the ceiling so that the bow girders were not visible from inside the hall. But this time, the bow girders were kept exposed. “The purpose was to keep one portion of the bow girders open for regular maintenance. Since earlier, the bow girders were hidden under a layer of lime and surki, we could not fathom the extent of damage due to seepage,” said an engineer.