Step 5. Stringers and track 23 June 2020 docgavUncategorisedLeave a Comment on Step 5. Stringers and track The hardtop edging is 15mm conduit which will be glassed in and then a strip routed out to provide the track for the vinyl windows and covers. To stiffen the 4m width of foam we have glued in three laminated cedar stringers (each laminate x 2 pieces of 15mm x 30mm cedar) using unidirectional glass as the glue. These will be further covered and glassed to finish off.