Plans submitted to the county council will see St Lawrence School, in Bowl Alley Lane, nearly double its capacity and includes 17 classrooms, main hall, physiotherapy rooms, sensory and calming rooms, and more.
Investment in the school will enable it to meet a wider range of needs.
There will be 55 standard car parking bays, four enlarged parking bays and four accessible bays along with capacity for up to 28 minibuses to drop-off and pick up from the school.
The old school will be kept open during building works in a bid to minimise disruption to pupils’ school year, and once the new building is opened, the old school will be demolished to be used as an outdoor playing field.
Lea Mason, executive headteacher of the Lincolnshire Wolds Federation, which runs St Lawrence and its sister school St Bernards in Louth, said: “While the works are happening, students will continue to access the current school buildings to maintain their education.
“We will be exploring increased community based activities, within the area, to ensure that the pupils have access to appropriate space for physical activities, whilst we are unable to use the field.
“This is an exciting development for the school, to create the much-needed provision and specialist space, to enable us to build on the opportunities to support our students, in all areas of need, within all need provision.”
Council bosses hope work will be able to start in autumn 2022.