We got someone in to do the shed roof thinking it would not leak for years.....it's leaking second time now. Already called him out last year and he gave some excuse of using rubber washers. I think he used some sealant and tightened some up. From the pics what are my options to try and seal it? Also at end I need some low expanding foam to fill the gaps which I can't seem to find . What are my options to fill them in?