I'm kind of glad someone said something about this sort of issue, because our team has a similar struggle. We represent a Catholic School and Parish, and we meet in the Parish Center, so we're basically allowed to stay there until the building closes, and that's about it. Because of this, our typical meeting schedule during build season looks a little something like this:
Mondays-Wednesdays: 5:30-7:30pm (We have to wait for our mentors to get off work and then, again, we stay until the building closes)
Thursdays (for Programmers only, Knights of Columbus also meets that night, so we have to keep the noise down): 5:30-7:30pm
Saturdays: 10am-2pm (Sometimes later if we decide to move the whole shop to our lead mentor's garage and work
)
I'm not sure how helpful this is, but I'm sure if your school is super strict on when they want you in the building, then there may be other teams in the area that are willing to let you use their space (or even a practice field if they have one!). There were a few teams that did this for us last season (Thanks 2137, 3539, 2612, 3098, and Bob Nichols of Kettering University!) and it really made a huge difference in how much we were able to get done (and how successful we were in competition).
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2016
Octo-Finalists at the FIRST in Michigan State Championship (12th Seeded Captain)
Winners at FiM Center Line District (1st Pick of the 4th Seed)
Excellence in Engineering Award at FiM Center Line District
Semifinalists at FiM Lake Superior State University District (5th Seeded Captain)
Quarterfinalists at FiM Kettering University District #1 (8th Seeded Captain)