Work to turn the fire-ravaged floors of Stephen Court habitable again started on Wednesday, two years and 80 days after the Park Street landmark caught fire, leading to 43 deaths.

A team of engineers and workmen pounded the crumbling walls and pillars with hammers and bore through them with mechanised drills to test their strength.

Some crumbled. The debris was neatly packed in a sealed plastic bag and sent for tests.

“To undertake a thorough restoration, we need to demolish some of the structures that had withstood the blaze. The residents should realise that their flats may look firm from outside, but their ceilings, floors and walls have crumbled,” said Asim Kumar Das, an engineer of the firm hired by the Stephen Court Welfare Association for the restoration.

While the blaze on March 23, 2010, had gutted portions of the fourth and fifth floors of Block II, almost all the floors of blocks I, II and III were declared unsafe by the civic body. Since then, only seven families have been living in blocks I and IV after signing risk bonds.

“It’s eerie to look at the devastated portions inside the building that was once our home. I wish the engineers finish work fast,” said Archana Agarwal, of Block II.

“The civic body had approved the restoration plan more than a year ago but it took us some time to start work as some residents were initially reluctant to pay,” said association secretary Debasis Guha Neogi.

The restoration cost, inclusive of making fire-safety arrangements, has been estimated at Rs 3.5 crore. “The stabilisation project would cost Rs 1.5 crore. We have been collecting money at the rate of Rs 100 per square feet from the owner/tenant of each of the 104 units to raise the amount,” said Neogi.

The association has set November 2012 as the deadline for the stabilisation work.