A £10m residential scheme being built by Mulalley has been damaged after a fire broke out on the site on Friday.
The roof of the 51-home development in Loughton, Essex caught fire just after 11am.
There were fears from the fire service that some workers might be trapped on the roof but all workers were evacuated safely before fire crews arrived.
It took the fire service just over an hour to put out the blaze.
Mulalley was contracted to build the three-storey development in 2016.
Around 20 apartments in one of the blocks was affected by the fire, most of which were ready with electrics, kitchen units and fittings already installed.
Epping Forest Council leader Chris Whitbread said the incident was a “serious setback” for the scheme.
He said: “It is too early to say what caused the fire but it is clearly large.
“The council has several roles: we are the client and this is a serious setback for us and all those people we are building these new homes for.
“In the longer term we will recover. Bricks and mortar can always be replaced and we will rebuild these much needed homes for local people.”
The council told CN that repair works could take a number of months, with most of this being due to damage caused by water used to put out the blaze.
It added that the rest of the site was in good condition and said work could restart on the unaffected blocks very soon.
Essex County Fire and Rescue Service Crew manager Ryan Fernandes said: “Initially we did not know if anyone was trapped, but soon confirmed that everyone had evacuated and began fighting the fire both from above and below.
“Crews worked incredibly hard to stop the fire spreading and quickly brought it under control.
“It was thanks to the great work of the crews that the damage caused by the fire is limited to the roof.”