I have a lead lined gutter valley with a pitched slate roof on 3 sides, which exits into a hopper above a down pipe. It is leaking into the house through the lead overlap. I've had 3 roofers look at it and they all give different advice. One said paint it all with Aquapol, but didn't know if it would crack when walked on for roof maintenance. One said just paint over the lead overlaps with Aquapol so I could just step over the overlaps for maintenance. And one said solder all the lead overlaps and cracks. I would have liked to line over the lead with EPDM rubber but they all say EPDM doesn't stick to lead. There must be an adhesive out there that would, or could EPDM be layed over loose? Advice please.