Making way for Mount Si High School freshmen, Snoqualmie Middle School’s 420 students will move to a campus that is familiar yet new.

The Snoqualmie Valley School District Board of Directors last week approved a $50 million middle school design based on North Bend’s Twin Falls Middle School for a 40-acre site on Snoqualmie Ridge.

Designers said the district will have to push to finish the new campus, which requires a bond, in time for the transition of SMS to a ninth grade annex in 2013.

“We need to be continually involved from this point onward,” Bill Chaput, principal architect at Hutteball & Oremus Architecture of Bellevue, told the board at a Sept. 23 meeting.

Asked to use Twin Fall Middle School as their prototype design, Chaput explained that they made sure not to make SMS an exact copy but rather use it as something that would be improved on.

The new Snoqualmie Middle School will not be an exact copy of Twin Falls, but rather an improved and tweaked design.

Twin Falls, Snoqualmie Middle School and city staff met this spring and summer to go over the plan and suggest changes.

“The school’s identity was important in a number of interviews,” Chaput said. “When you arrive in the building, it’s the reverse (mirror image of Twin Falls). The children and staff will feel they have their own school and identity.”

The design phase began in June, as designers worked to make the school fit the topography of the site, off Elderberry Avenue and Carmichael Street, and the Ridge community,

Changes include location of storage, wall thickness, classroom access and sustainability improvements. A major difference was the use of day light throughout the school and gymnasium.

“We were finding things that provide a resource for teachers, things that provided quality and that really did something for the district,” said Scott Williams, Hutteball and Oremus project architect.

School board member Scott Hodgins questioned placement of buildings, wondering if it was a wise choice to give the fields a better view than the school.

“We would add about half-million (in costs) if we used Carmichael as our main road,” Chaput said. “We would do much more intensive development. We wanted to minimize the presence of the building to the surrounding residents by putting small classroom wings out on the street frontage.”

Fields were also placed adjacent North Neighborhood Park so the community would be able to use them during non-school hours and weekends.

Hodgins also questioned whether the school capacity reflects long-term growth.

“This will be the central middle school,” Hodgins said. “I don’t want to add portables, because then we’ll be missing the mark. Let’s make sure we build it large enough.”

Assuring Hodgins that the school will address needs through 2016, district Operations Director Clint Marsh said the building is designed for 600 students and can absorb 800 students before feeling impacts because of generous common areas.

The board’s next step is to discuss the design at a work session, 6 p.m, Thursday, Oct. 7, at the district office, to determine the scope for a middle school bond.