I've just rolled out sheds and let them dry out. They usually don't become so brittle that they break apart the instant you touch them, although they are still fragile. I've let me son take several sheds into school that way, and when they're all banged up I just toss em and save the next one.

I wonder if you could use a spray varnish/sealant to make it a bit sturdier? I've never tried it, but it might be worth looking into.... maybe.