Insurer National Interstate Corp. said it soon will start building a $25 million office building on its Richfield campus.

Wednesday’s announcement follows the authorization Monday of Ohio Job Creation Tax Credits for the project.

National Interstate said it will put up a 117,000-square-foot office building for subsidiary National Interstate Insurance Co. that will allow the company to add 200 jobs to the more than 500 it now has in Richfield. This will be National Interstate’s third building.

Construction is expected to start in the last three months of the year and be finished in 2017, the company said.

“We are very excited to announce the construction of this new building,” Tony J. Mercurio, National Interstate’s president and chief executive officer, said in a statement. “With our significant growth over the past several years, we need to continue to hire talented employees and that creates a need for additional office space. The construction of this third building at our headquarters location demonstrates our commitment to Richfield and Northeast Ohio as well as our dedication to being an employer of choice in the region. When completed, our picturesque and convenient campus will accommodate approximately 1,000 employees. We take pride in providing our employees with a high quality work environment which will be further enhanced by this project.”

National Interstate said it is partnering with and has the support of both the village of Richfield and the Revere School District.

“What a great opportunity to have National Interstate continue to invest in the village. National Interstate has been a Richfield resident for over fifteen years and we’re excited to continue this relationship for years to come,” Richfield Mayor Bobbie Beshara said in a statement.

“We look forward to partnering with National Interstate in the future, including offering educational programs such as internships to our students,” Matthew Montgomery, Revere School District, superintendent, said in a statement.

National Interstate also said is collaborating with JobsOhio, a non-profit organization designed to drive job creation and new capital investment in Ohio.

National Interstate sells insurance for passenger, truck, and moving and storage transportation companies.

The Ohio Tax Credit Authority on Monday said National Interstate will receive tax credits totaling an estimated $1.77 million over seven years if it creates 217 jobs. The tax credits are measured as a percentage of the state income tax withholdings for all new employees hired under the tax credit program.

National Interstate said it expects to generate nearly $14 million in new annual payroll with the new jobs by Dec. 31, 2020. Current annual payroll in Richfield is $33 million.

National Interstate also needs to maintain operations in Richfield for at least 10 years.

National Interstate Corp. is being bought by its majority shareholder, Cincinnati-based American Financial Group, also known as AFG. American Financial will pay $32 cash per share for National Interstate.