The Corodrain range of BBA approved valley troughs are manufactured in GRP as an economic and durable alternative to using lead and all conform to NFRC Technical Bulletin 28. Corodrain valley troughs can be used on both slate and tiled roofs and with any combination of double or interlocking slates, clay or concrete tiles. Corodrain can also provide a weatherproof seal between roofs of terraced houses or where a new roof needs to join an existing roof.  Options include A, B, D and E valleys and also the Diamond 60 range of D and B valleys with enhanced durability which has been recognised as matching code 7 lead.