A primary school stretched to the limit will have six mobile classrooms in the playground to cope with overcrowding.
In total, 10 Falkirk schools will have modular units in their outdoor space in August to make up for the lack of space.
That means 20 per cent of primaries in the Falkirk Council area are forced to put children outwith the main school building to learn.
Kinnaird Primary School had four of the mobile classrooms in their playground for this academic year, but to cope with the increasing roll, a further two will be added in August and another two potentially being added within the next couple of years.
Colin Fawkes, chairman of Kinnaird Primary Parent Council, said the situation isn’t good enough.
Colin, dad to primary pupils Olivia (10), Emily (8) and Kinnaird Nursery pupil Elliot (4) said: “Kinnaird is stretched to it’s limits.
“The playground at the school was not big to start with and now the kids are going to have six of these large units on the grounds. It’s not fair on them, children need plenty of space to play as well as learn.
“The council have told us there is no money in the five year plan to pay for the school to be extended, and we are left wondering how the school, pupils and teachers will cope.”
Kinnaird Primary was financed with money from the house builders that created the village on the site of the old Bellsdyke Hospital.
However, at a meeting of Falkirk Council’s education executive on Tuesday, councillors admitted they got their sums wrong.
Councillor Tom Coleman said: “Part of the problem at Kinnaird and at Maddiston is to do with planning consent.
“At Kinnaird, the original plan from the housebuilder was to build eight to 10 houses per acre but changes in the economy meant they built lots of flats and more families than forecast moved into the area.”
Primary schools can cope with an occupancy of around 90-95 per cent and high schools up to around 88 per cent.
Kinnaird has 108 per cent, with Ladeside in Larbert at 106 per cent and St Joseph’s in Bonnybridge at 114 per cent. In total seven schools are over the limit.
Maddiston has a 98 per cent occupancy and with house building still booming in the catchment area and at Kinnaird, the problem looks set to get worse.
Speaking at the meeting, Gary Greenhorn, head of educational planning and resources, said they would be trying to extend Kinnaird and Maddiston primaries, although it was not in their capital expenditure for the next five years.
Mr Greenhorn said: “Modular units are modern, well lit, well serviced structures – not the huts from our school days.
“They are excellent space for learning, but if a school is going to need modular units for more than five years, we look at making them permanent structures, Because of that, we are looking at extending the schools. Extending has challenges, especially in areas without a lot of space but we are speaking with the head teachers and parent councils to come up with a way forward.”
He added education services can apply to the capital builds fund to pay for the work.