(CNN) After more than a year of tense negotiations with the school district, Denver teachers overwhelmingly voted to strike late Tuesday.

Following two days of voting, the Denver Classroom Teachers Association (DCTA) announced that 93% of its members approved a strike after negotiations failed.

"Denver teachers overwhelmingly agreed to strike," lead negotiator Rob Gould said during a news conference on Tuesday.

Members of the DCTA have begun meeting to make signs, write chants and practice picketing, according to CNN affiliate KDVR

"Oh, we have to strike," one teacher told KDVR. "We have no choice."

Schools will be open Wednesday, but the strike could happen as soon as Monday, January 28, Denver Public Schools Superintendent Susana Cordova said during a news conference on Tuesday.

The union had been negotiating with the district for 14 months to overhaul the compensation system, which the union says is directly linked to the city's teacher turnover rate.

JUST WATCHED Teacher: 'I'm not being as effective as I could be' Replay More Videos ... MUST WATCH Teacher: 'I'm not being as effective as I could be' 01:00

Turnover, the union said, is high and increasing. According to the union, 31% of Denver teachers have been working at their school for three years or less.

"The revolving door is a crisis for kids and families who count on DPS to consistently provide a caring, qualified and experienced teaching staff at every school," the union said in a news release announcing the result of the vote.

DCTA hopes to alleviate the high turnover with changes to Denver teachers' pay, which the union says prohibits some teachers from paying for housing in the area and forces some to take on second jobs. As an example of the hardships Denver teachers face, the union cited a teacher who taught in Indianapolis and Chicago before moving to Colorado. The teacher makes $10,000 less in Denver than he did in Indianapolis and $15,000 less than he did in Chicago, the union said in its statement.

Take home pay varies year to year, the union said, because the pay system is full of unpredictable bonuses to compensate for a low base pay.

"I didn't expect to make a lot of money," Denver teacher Amber Wilson told CNN affiliate KFVS . "But I didn't expect in my late 30s and early 40s to be waiting with bated breath for my paycheck to come at the end of the month."

The union said its proposal could be funded if some of the $4 million designated annually for administrator bonuses was invested in teacher salaries.

"They're striking for better pay, they're striking for our profession and they're striking for Denver students," Gould said.

On Friday, the union and Denver Public Schools were unable to reach an agreement on a fair compensation system for 5,700 teachers and special service providers.

"It is very disappointing. We fully committed to negotiations for more than a year with a goal of keeping more of our talented and dedicated teachers in the district," said DCTA President Henry Roman.

According to Roman, the Denver Public Schools' final offer came up $8 million short of the funding the union sought to create a compensation system that would attract new teachers while valuing the service of current staff.

"It's only 1% of their entire budget -- less than 1% -- to give us that $8 million that would help us get our teachers where they need to be," Wilson told KFVS.

This would be Denver's first teacher's strike since 1994.

"I remain very committed to working with our teacher's association to reach an agreement," Cordova, the superintendent, said.

"We are very committed to keeping schools open. Even with this strike vote there is nothing that will change for school tomorrow; so tomorrow schools will be open," she said.

But come Monday, the district may be paying substitutes double the usual pay to have a teacher in the classroom, according to KDVR

"I want to ensure that the community knows we love our students, we love this city and we're going to try and make sure that we're communicating with our parents and with our families to make this work," Denver teacher Moira Casados Cassidy told KDVR.