Boeing said Tuesday that employment at its Renton 737 plant will swell by roughly 1,200 over the next couple of years as it boosts production of the single-aisle jets.

Boeing said Tuesday that employment at its Renton 737 plant will swell by roughly 1,200 over the next couple of years as it boosts production of the single-aisle jets.

That figure will include employees transfering from other Boeing sites as well as new hires.

Spokeswoman Liz Verdier said the company will also expand an existing building on the Renton site, adding 75,000 square feet that will be used to store equipment such as seats and inflight entertainment systems supplied by vendors and installed near the end of the assembly process.

Boeing currently rolls out 31.5 jets a month from Renton. In January 2012, that will jump to 35 a month and in the spring of 2013 it will rise again to 38 a month.

The jobs boost will come in two phases of about 600 people, months in advance of each of the production rate increases.

According to the latest data the company provided to the state, at the end of 2009 Boeing employed 10,400 people in Renton.