The Ronald McDonald House, which offers shelter to families of children with life-threatening illnesses, will roughly double in size and add 69 rooms under an expansion plan the Palo Alto City Council enthusiastically approved Monday night.

In a unanimous vote, the council swiftly green-lighted a proposal by Ronald McDonald House to build a three-story addition directly next to its existing facility near Sand Hill Road and El Camino Real. The current complex has 47 rooms and has seen a surge in demand in recent years – demand that is expected to climb even further because of the pending expansion of the Lucile Packard Children's Hospital. With space limited, the House has been forced to turn away between 40 and 50 families a day.

"We do a tremendous job of taking care of the 47 families that stay with us at the House every night," Annette Eros, chief executive officer at Ronald McDonald House, said in a statement. "However, we are deeply concerned about the 40-50 families on our waiting list every day. This approval moves us one critical step further to providing the solution for these families in crisis, which is a larger facility with more capacity."

The council had nothing but praise for the organization and for its proposed expansion, with Councilman Marc Berman calling the facility a "gem in the crown of the city" and Councilman Larry Klein calling its expansion a "great project."

Councilman Pat Burt said he "can't think of any mission of an organization in our community that is more admirable and more important than what you do." Councilwoman Liz Kniss was more concise.

"Only the Grinch would vote against this tonight," Kniss said.

Ronald McDonald House officials said the average length of stay has grown dramatically over the years, largely because of medical advances. In 2003, when the facility expanded from 24 to 47 rooms, the average stay was about six days. It has climbed by 500 percent since, according to Ronald McDonald House officials.

Work on the 52,000-square-foot addition is expected to begin next year.