The owners of flats in two Manchester apartment blocks built with flammable cladding will have to pay an estimated £3m to have their homes made fire-safe, following a ruling by a tribunal.

Vallea Court and Cypress Place in the city’s Green Quarter failed fire safety checks last July and were found to have cladding similar to that on Grenfell Tower.

The freeholder of the two Manchester blocks took apartment owners to tribunal, arguing that as leaseholders they were responsible for replacing the aluminium composite material cladding. The buildings, which include 345 flats, were developed by the Australian company Lendlease, which then sold the freehold to the investment firm Pemberstone in 2015.

The tribunal concluded on Thursday that the apartment owners should pay for the replacement of the cladding (at a cost of £10,000 each) through their service charge, plus Pemberstone’s legal fees. It also ruled that the owners of flats in Vallea Court should also be required to pay for a “waking watch”, to guard one of the blocks until it was made fire safe.

The leaseholders have previously highlighted a letter they received from Lendlease when they first bought their flats, which read: “Lendlease will undertake, at our expense, to complete any accepted defect that has arisen as a result of either faulty materials or defective workmanship.”

Katie Kelly, who lives in one of the blocks, told the Guardian this month: “If you bought a new car from a manufacturer and it suddenly set on fire as you were driving it and they all had to be recalled, you wouldn’t be expected to pay for the fact that it was faulty.”

The leaseholders – many of whom bought their flats through the government’s help-to-buy scheme – represented themselves at the tribunal, raising money for a letter from a lawyer using crowdfunding.

The tribunal decision follows similar outcomes in legal battles over blocks with flammable cladding across the country. The owners of flats in the Manchester buildings have pointed to the decision this year by Barratt Developments to pay for new cladding on the Citiscape block in Croydon, south London, despite a tribunal ruling that the costs should fall on the leaseholders.

Barratt was applauded by Sajid Javid, then housing secretary. “Delighted Barratt Developments have told residents of the Citiscape flats they will cover fire safety and cladding costs,” he tweeted. “This is the right thing to do and I want to see others follow their lead to protect leaseholders from unfair costs.”

A spokesman for Pemberstone said: “The tribunal is an independent forum to which landlords and leaseholders can apply to establish clarity on issues of this type. It is particularly appropriate for large schemes like this where there are 345 apartments, of which 75% are owned by investors and some of whom are located overseas.

“Now that the tribunal decision has been issued, this should allow us to establish a clear way forward.”

The company said it appreciated the concerns of those living in the blocks and that the buildings’ managers were working closely with the fire service to keep people safe. “We will consider carefully and sympathetically how any payments can be structured to spread the cost over time,” said the spokesman.

A spokesperson for Lendlease said: “Shepherd’s Construction, were responsible for the design and build of Vallea Court and Cyprus Place, and the current owner of the building is Pemberstone Ltd.”