Thousands of commercial janitors in the Twin Cities will get a bump in wages and paid sick days under a tentative four-year contract agreement reached Saturday, which capped months of negotiations and averted an open-ended strike that was set to begin Monday.

Service Employees International Union (SEIU) Local 26, which represents more than 4,000 Twin Cities commercial janitors, negotiated a wage increase of $2.20 over the course of the contract for full-time workers, with some part-time workers going from $11.12 an hour to $16 over the next four years. All full-time workers will receive six paid sick days by the second year of the contract.

“We’ve landed the best contract that we’ve ever had,” said Local 26 President Iris Altamirano. “This win is for all of us.”

Local 26 members include janitors who clean the IDS Center, Capella Tower (which houses the Star Tribune offices), the Ecolab building, and the Wells Fargo and U.S. Bank buildings in both Minneapolis and St. Paul.

More than 100 janitors held a one-day strike last week and formed a picket line in downtown Minneapolis, waving signs and beating drums along Nicollet Mall. The union’s negotiations with 18 companies, most of which are part of the Minneapolis-St. Paul Contract Cleaners Association, spanned more than four months and 22 bargaining sessions, Altamirano said.

The tentative contract agreement reduces the cost of health insurance for individuals and families and incorporates sexual harassment policies.

Workers also won funding toward a green education initiative, which will look at expanding the use of nontoxic cleaning chemicals and certifying janitors in environmentally conscious cleaning practices. The joint labor-management fund will also bring representatives of the union and the companies together to study ways to lower carbon emissions from downtown buildings and improve energy and water conservation, Altamirano said.

“It’s truly a space where we’re looking ... towards creative solutions to big problems like climate change, like green practices, like health and safety concerns,” she said.

Attorney John Nesse, who represented the Cleaners Association in contract negotiations, said the employers were happy with the deal — and to avoid a strike.

“The employers are looking forward to focusing on their work,” he said.

Union Vice President Elia Starkweather, who has cleaned Ameriprise Financial headquarters in downtown Minneapolis for nine years, said she was proud of members for sticking through the negotiations.

Last week’s strike and the threat of another, which would have been open-ended, helped janitors secure desired increases in wages and benefits, she said.

“Our campaign slogan was ‘Fighting Today for a Better Tomorrow,’ and I believe because we were so united we really were able to win an agreement that will build a better tomorrow for thousands of janitors, our families and our planet,” Starkweather said.

The commercial janitors join 2,000 security officers who agreed to a new contract last month. The remaining members in the union — retail janitors and airport passenger service workers — are still working to reach deals.