Volunteers needed to fix a leaking roof for Józef in Kraków

I'm a school janitor living in Kraków. During the last storm water started coming through the ceiling in 3 places, and the kids' bedroom is no longer usable. A roofer quoted $1,800, which isn't something I can pay. The good news: a local hardware store has donated the roofing sheets and nails. What I don't have is people to do the work. I'm looking for three or four volunteers who can help over two Saturdays. Experience helps, but it isn't essential - I'll have a licensed roofer supervising for safety. All you need is to be comfortable with heights or willing to help from the ground. I'll provide lunch, water and lots of thanks. The work will be done on the ground and roof with proper harnesses. If you can only help for a few hours, that's welcome too. Thanks for being kind about this.