This was a sloping GRP roof with a roof lantern. The design of this was a bit awkward and we had to create our own sloping angles to the rear and right-hand side, before we fitted our preformed trims to the perimeter and around the roof lantern. We then bandaged all trim joints and corners before installing our 1st layer GRP using activated liquid resin and fibreglass sheet roll matting. Activated liquid topcoat was then applied the same day and the lead flashing to wall and a further topcoat added a few days later to finish off the system. Two topcoat layers should always be applied when installing a GRP system. Your installer should then feel confident enough, as we do, to guarantee the install of this roof for 25 years.