What’s the science behind single-wall tent fabrics?
I have yet to find a definitive answer on how well some of the higher-end single-wall tent materials work, products like Bibler's ToddTex, three-layer Gore-Tex, and Integral Designs' Tegraltex. Some say these fabrics are great, very tough, and result in little or no condensation, others the opposite. But no one seems willing to crown a king of the single-walls. Is it too tough to call? I like the simplicity of a single-wall design, but tents like the Sierra Designs Hyperlite AST look to be very good and compete well on weight and packability. What's your take? Luke Minneapolis, Minnesota
Until recently, single-wall tents tended to be constructed of high-tech, very expensive fabrics. Not Gore-Texstrictly speaking, Gore-branded Gore-Tex is not approved for tents because of its lack of fire-retardant coatingsbut chemically similar materials such as ToddTex and Tegraltex, as you note. Both are very similar, if not the same: a PTFE membrane (polytetrafluoroethylene in its full glory, a material identical to “classic” Gore-Tex) is bonded to water-repelling ripstop nylon on the outside and fuzzy, moisture-absorbing fabric on the inside. The fuzzy inner stuff is supposed to grab water and hold it until the PTFE membrane can pass it to the outside. But, in practice, that material can also simply grab moistureand hold onto it. Nonetheless, these are good materials that often work extremely well.
Anyway, in part because of these exotic fabrics, and in part because of the complicated construction required of single-wall tents (many vents; bombproof engineering to shore up the inherent vulnerability of a single-wall design), these tents were wildly expensive: $650 for Bibler’s Ahwahnee 2, for instance, plus another $125 if you wanted the add-on vestibule. I’ve liked the Ahwahnee when I’ve used it, but generally I feel these tents are best for really hard-core mountaineering, where weight and strength are paramount considerations. I don’t think you can justify the expense for most uses. Plus, the simple fact is that most double-wall tentsdue to an insulating layer of air between the canopy and flyare warmer in cold weather and cooler in warm weather. They usually suffer from fewer condensation problems, because the canopy of double-wall tents is typically made of an extremely breathable ripstop material.
What’s interesting in the past few years, though, has been the advent of “cheap” single-wall tents. These use a completely waterproof canopynot even with the pretense that they’re “breathable”and instead rely on good venting and a certain tolerance for moderate condensation. The most successful example has been Mountain Hardwear’s Waypoint 2 ($250; www.mountainhardwear.com), which I have used and think is terrific for backpacking and bike touring. Not quite rugged or roomy enough for mountaineering or expedition use, but light and weather-resistant everywhere else. Marmot made a fine, very similar tent, but discontinued it this past year.
Meanwhile, new materials and better designs mean that double-wall tents just keep getting lighter. A good example: Marmot’s Hypno ($349; www.marmot.com), which weighs just a touch over five pounds, yet has scads of interior room, a full-coverage fly, a vestibule, and a huge front door. In short, it’s a tent with the same basic specs as the Ahwahnee without the vestibule, for almost half the price.