Abstract: A spacer/seal for use in multi-pane glazing units, to provide a thermally non-conductive peripheral hermetic seal comprises a hollow tube of selected cross-sectional form, built up of a laminated construction of helically wound laminated layers and incorporating a layer or layers of gas impermeable barrier material to ensure long lived hermetic sealing characteristics. The construction may include respective layers wound to opposite hand, and layers wound to different lead angles. Also, the gas impermeable barrier layer or layers may be selected from materials that serve as adhesive to the laminated structure. Suitable barrier layers may be selected from polyvinyl alcohol, polyvinylidene chloride, thermoplastic polyesters, ethylene vinyl alcohol copolymers, and combinations thereof.