Abstract: A mechanically strong, airtight, watertight seam provides for joining two panels of industrial strength fabric or material. The inventive seam has two connection systems. One system is a mechanically strong structural connection which is used to make the seam as strong as the fabric panel material. A second system is an all plastic slide closure in the form of a zipper connection which overlies the structural connection, joins the panels into a single cover, and makes the seam airtight, watertight and maintenance free.