A tower block subject to an emergency evacuation was not constructed according to plans, a city councillor has said.
More than 400 residents were forced to leave Barton House in Bristol on Tuesday, with the council declaring a major incident.
Kye Dudd, cabinet member for housing services and energy, said the issues lay with its concrete sections.
"If the building was built to design we wouldn't have this problem," he said.
"The issue is within the construction of the building and the job that was done at the time, it wasn't built to the design specs - that's the problem we're dealing with."
Bristol City Council (BCC) declared a major incident after building surveys showed Barton House, built in 1958, would be unsafe in the event of a fire or explosion.
The council said Barton House was not affected by the same reinforced autoclaved aerated concrete (Raac) which caused issues in many schools and hospitals.
Mr Dudd said: "I had a briefing on Monday where the report from the structural engineer was presented to me and it looked really bad, so I said to the team we need to prepare for a potential emergency evacuation.
"But we also had to seek further advice from the fire brigade, so the following day we had another meeting...and we had some prep on where we would potentially move people.
"We had to take the decision with the information we had as the safety with residents is paramount."
The council added it had notified the government's Department for Levelling Up, Housing and Communities about the structural issue which forced the evacuation.
BCC said this latest issue did not affect other buildings in the city.
People were told to pack enough clothes for a day or two and stay with friends and family, or go to rest centres, the council said.
Many were taken on buses to temporary accommodation, carrying their belongings in plastic bags and suitcases.
Wilfred Stewart lives in a flat on the 10th floor of Barton House.
The 50-year-old showed the OceanNewsUK around his flat, which has cracks in the walls and in what appears to be supporting beams.
He said he had painted over the cracks a number of times but they had kept reappearing.
"This crack has been here for years and it's by my back door. The wall is almost separated from the door," he said.
Mr Stewart said there were lots of elderly people who lived in the building, as well as children.
He added: "Some people managed to get hotels for the night but a lot of people went to the mosque or the GP clinic over the road.
"I hope we get better communication today."
A woman who has been living at the building for nine years said that after being evacuated she stayed at a friend's home with her two children.
But she added: "After tonight I don't know where I am going to go."
Nuh Sharif, a Barton House resident, said his family spent a "difficult" night in a hotel.
He said he did not think they would ever return to living in Barton House as he would not feel safe.
"I don't want to put my wife and kids at risk," he said.
Mr Shariff added: "Last night was very difficult for me and my kids. I am not sure what will happen next. [The Council] put us in a hotel last night and we didn't sleep.
"We have come back to try and get more information about what next."
Meanwhile, a first-floor resident, who has been living in Barton House for six years, said she decided to stay in the tower block on Tuesday night.
"I didn't leave. There was advice to go along to certain points, I went along and nobody knew what was going on," she said.
"There is no update yet today and I am going to be back tonight."
