The incident happened just before noon on Sunday when the Scottish Fire and Rescue Service responded to calls from residents in the Portal Road block – which contains numbers 75 to 80 – about a blaze on the first floor landing.
Thankfully there were no injuries, and the fire service quickly had it under control before it could spread inside any of the flats.
Police Scotland said officers are currently investigating the incident.
A spokesperson said: “Police in Forth Valley are investigating following a deliberate fire in Grangemouth in the Portal Road area at around 11.55pm on Sunday, January 27. The Scottish Fire and Rescue Service attended and extinguished the flames. Local residents were evacuated temporarily as a precaution.
“Inquiries are ongoing and anyone with information is asked to contact Police Scotland on 101, quoting incident number 1874 of January 27, or Crimestoppers anonymously on 0800 555 111.”
Residents have told of a series of smaller fires set just a day before the major blaze occurred.
One man, who did not want to be named, said: “There had been bits of paper – the close cleaning rota – set on fire on the first floor and someone had also tried to set fire to a towel on the Saturday.
“We just thought it was kids messing about. I had taken pictures of the damage and I was going to take it to the council to report it – then we had the fire on Sunday.”
The man’s wife was actually trapped by the blaze, which fortunately did not get through the front door of the family’s flat.
He added: “She opened the door and the fire rushed up in the draft. She was safe in the flat and firefighters were with her, putting a ladder onto the veranda outside and talking to her as the other firfighters were putting out the fire.
“I came home from work and saw three fire appliances, police and an ambulance outside.”
The door to the close is normally secure and the service button does not work on a Sunday, so tenants are still trying to figure out how the fire raisers gained access to the close in the first place.
One family is too scared to return to their flat and have asked Falkirk Council to provide temporary accommodation.
The resident said: “Even though the fire was right outside our door they said there was no damage to our flat and we can still live in it, so we didn’t need temporary accommodation.
“They said there is no direct threat and no danger of this happening again. They took our details and said they would talk to Police Scotland to see if there was a threat to anyone in the flats.
“My wife does not want to come back here and you don’t want to bring your kids back to this. They are staying with family at the moment.”
Tenants also stated the council initially told them it was the residents’ responsibility to clean up the fire damaged close themselves.
A Falkirk Council spokesperson confirmed emergency repairs workers had attended at the block on Monday after to assess the damage. The flats’ electrics were not compromised and the entry doors were found to be secure.
A crew from the council was scheduled to attend on Wednesday to start the clean-up operation in the close, cleaning and painting all levels.