Roof Top Garden for the High School?

Today I had a structural engineer from DeWolfe Engineering come talk to my class about what he does and also about the possibility of putting a green roof on the school - my students' idea. 

I personally haven't decided what I think about it. 

First of all, we've got to find the plans for the roof, and no one has found them :( I think it'll basically come down to this: either the structure was built with strength enough to one day support an additional floor (in which case we're good to go), or not (in which case, it's probably not going to happen).  And it really could go either way. 

We've got a potential grant lined up that could help us pay for it through enVision Montpelier , but we've got to get some of these issues squared away first. 

It was totally good  having this guy come in cause, well, I don't know jack about structures. Engineering was not my bag.  Paper physics is so much cleaner. (I am converting into a hands-on person, but it's a slow process).