I am looking to replace my garage roof with 3" corrugated PVC sheet. I will need to flash one short edge AND one long edge. Flashing the short edge will be no problem thanks to products like Screwfix part no 13229 (3" ASB wall flashing. But what do I do about the long edge where the corrugations will run parallel to the wall? Does anyone know if there are any products out there specific for the job? Or must I stick with timber batons, nails, mastic, flash tape, etc? Thanks.