The airport’s roof has got walkways to reduce the strain on joints from the weight of maintenance workers and prevent leaks during rain. But the walkways will only help deal with humans and not birds.

There are skylights across the terminal to let in daylight. “Birds have taken a liking to the skylight joints. They peck at the joints and leaks appear every day,” an official said on Tuesday.

Water drips from the leaks every time there is heavy rain and buckets have to be placed on the floor of the departure level to collect water.

The authorities have decided to replace skylight joints, a process that may stretch across months.

“The construction of steel walkways on the terminal building’s roof was completed recently. The maintenance workers are using the walkways and there are also fall-arrest system with high strength wires for the safety of the workers. Earlier, they would have to walk on the joints, resulting in damage that would cause leaks. The walkways will protect the joints,” airport director Kaushik Bhattacharjee said on Tuesday.

“There are 11,000m of skylight joints that are connected with the roof with silicon sealants. These are prone to damage by bird pecking.”

The walkway project was initiated last year.

The terminal’s roof is spread across 7,500sq m. The steel walkway stretches 6,570m and the fall-arrest system 5,500m.

The Telegraph has reported on several occasions how the airport authorities would struggle to plug the leaks. Engineers said rainwater would seep into the terminal through widening gaps in the roof joints. Although the gaps were repaired, new ones would appear.

As for the problem caused by bird pecking, a senior official said it was difficult to address.

Sealant, which is used to block the passage of fluids through a surface or joints, has been extensively used in the skylight joints.

“One cannot stop birds from pecking. So, the only option is to replace the damaged joints,” the official said. “The skylight joints will now be replaced and this will be a continuous process.”

Airport and airline officials said they had to wait for a downpour to find out whether the walkways were effective.

“Now there is hardly any rain. The real test would be when it rains heavily,” said an official of an airline.