Factories and construction sites will begin the process of reopening this week under a four-phase plan Gov. Charlie Baker released May 18.

By next week, offices outside of Boston will reopen under the gradual process Baker outlined in a press conference Monday that will end with what he called the “new normal.”

“As we start the phase return to our new normal, we are going to ask people once again to rise to the occasion as we continue to fight this virus,” Baker said.

Each of the four phases of reopening will last at least three weeks but may last longer depending on public health outcomes.

“The framework released today can serve as a guide for a cautious, phased-in approach to reopening the economy,” he said in a statement on Monday, “driven by clear public health criteria and safety guidelines that will keep our residents and workers healthy, and the Commonwealth moving in the right direction.”