Students and parents at a three-year-old south Ottawa high school are urging the provincial government to expand the school due to overcrowding.

Grade 11 student Anna Clement fears she will spend most of her graduating year at Longfields-Davidson Heights Secondary School in a portable. (CBC)

Longfields-Davidson Heights Secondary School at 149 Berrigan Dr. in Barrhaven opened in 2009 with a plan to have students from Grades 7 to 12.

So far the most senior students have only reached Grade 11 and there are plans to keep them in the school for Grade 12 next school year. But the school is already 100 students over-capacity.

"I personally don't want to have my graduating year in a portable. I feel like that's what it's going to be, and I'm not too happy about that," said Grade 11 student Anna Clement, who is heading a petition in favour of expanding the school.

Clement is currently collecting signatures in support of her cause. The evidence is there, too.

Longfields-Davidson Heights already features 10 portables and the Ottawa-Carleton District School Board estimates 14 more will need to be added next year and possibly 11 more by 2015.

By then, students expect portables will overtake the school's sports fields.

Local politician says taxes should buy students a classroom

There is also a Catholic high school, Mother Teresa Catholic Secondary School, just a few kilometres away on the same road. But that is not a solution, students and parents say.

Longfields-Davidson Heights Secondary School is just three years old and is already 100 students over-capacity while serving Grades 7 to 12. (CBC)

The Conservative MPP for the area, Lisa MacLeod, showed up to a meeting Thursday evening to talk to parents and students and said she agreed with their concerns.

"We think that's not acceptable. These parents are paying taxes to the board, they're paying taxes to the provincial government and they expect their kids to be in a school, not a portable in the backyard," MacLeod said.

It is more worrying, both MacLeod, students and parents say, because the overcrowding problem at the Barrhaven school is likely a long-term one, but any fix is just temporary.

This week's census results show the area's population skyrocketed by 25 per cent between 2006 and 2011, making it the fastest growing community in the Ottawa-Gatineau region.