The galvanized roof parts of the tower saw several damaged and displaced sections, causing rainwater to pool and damage their structures further. The cathedral had to use several metal plates to temporarily block such parts from the rain.
In order to renovate the two galvanized towers, 26 m tall and weighing a total of 23 tons, the construction unit had to install scaffoldings imported from Germany, which is over 60 m tall and have 29 floors.
Inside the two towers, systems of 16 steel beams can withstand a weight of 72 tons, three times the total weight of the towers. To reinforce the frames within the towers, the construction unit used over 600 types of screws and nails imported from Germany.
Inside the towers are a set of six bells, weighing over 30 tons and with an average height of 3 m. They were made in France in 1879 and their sound can be heard from 10 km away. However, the bells have stopped being rung since January 2020 so that they can be renovated.
Xuan said the antique set of bells was very rare. However, after over a century, the cemented part of the bell tower has been damaged. Ringing the bells with too much force may cause the tower to collapse.
Similar to the galvanized towers, the renovation of the bell tower would require many blocks of Pierre de Masangis stone to replace the damaged blocks.
At Christmas last year, the cathedral had installed a set of 25 bells, weighing 326 kg, imported from Germany to use while the original bells were being renovated.
Along with the towers, replacing hundreds of thousands of damaged bricks on the walls of the cathedral is a difficult and time-consuming task. The damaged blocks were replaced by bricks crafted in Germany.
Workers make measurements and use tools to cut the bricks. These bricks are then embedded into the walls using special cement, reinforcing the walls.
Priest Xuan said the renovation will get more difficult over the next four years.
"A solution needs to be found to deal with the fact that water has been penetrating the cathedral from the ground up, affecting its structures. The construction unit has been sending plaster samples to Belgium for analysis, paving the way for a solution," he said.
The Notre-Dame Cathedral Basilica of Saigon, located in HCMC's District 1, began construction in 1877 and was finished after three years.