Instead of attending classes, pupils at Pretoria Secondary School in Sunnyside are being forced to go out on excursions. In the past week the pupils and teachers visited the Pretoria Zoo.
This was then followed by a trip to a museum, said a parent and member of the school's governing body.
The school carried the costs of the excursions.
"A lack of classrooms and too many pupils means that all the children cannot attend classes at the same time," said the mother of a daughter in Grade 10.
To overcome the problem, the school rotated its classroom space to accommodate classes in a series of shifts, she said. The teachers and 700 pupils shared 12 cramped pre-fabricated classrooms.
"One class attends lessons and another goes on a trip," said the concerned parent, pointing out that the state of the school's facilities failed to justify the monthly cost of R500 parents were obliged to pay.
"We have to pay, but our children cannot attend classes," she said.
When the school opened in January, overflow pupils received classes on a rubble-strewn Rissik Street plot with only one tap to cater for the thirst of about 250 children.
There were also no ablution facilities and children had to brave Rissik Street's traffic to use the ablution facilities at the school's main Gerard Moerdyk Street campus.
A spokesperson for the department of education, Tim Makofane, promised in January to remedy the school's plight.
"We will soon be erecting additional mobile classrooms to cater for the overflow, as well as sorting out the sanitation facilities," he said.
Late in the past week, despite having no desks or chairs, the pupils moved into their new classrooms.
A row of chemical toilets had also been installed.
To address the problem of pupils having to sit on the floor, the department delivered about 180 desks and chairs on Monday.
Makofane undertook to arrange delivery of additional equipment, saying the department was investigating the possibility of relocating the school.
"We are currently busy with investigations into suitable sites for a school as a long-term solution to the problems," he said.
Deliveries on Monday and Tuesday of text books also assisted in making conditions easier for teachers and pupils.
A Grade 8 pupil, Freddy Mnisi, said the pupils were happy to receive the new desks and chairs.
"Some classes still sit on the floor in the new classrooms. At least it is better than sitting outside on the ground like before," he said.
The principal, Columbine Commaille, said she needed to make do with the facilities at the school's disposal.
She said the problems were as a result of too many pupils attending the school.
"We are way over our limit in terms of the number of children the school is designed to accommodate," she said.