This FAQ explains what “Ultra” fabrics are, how they’re used in ultralight backpacking gear, and how they differ from other fabrics for making backpacks, tents/tarps, and stuff sacks. You’ll find pros and cons, care, repair, and buying tips, plus comparisons with Dyneema Composite Fabric (DCF), Woven Dyneema, X-Pac, Robic Nylon, and traditional nylons.

Q: What are “Ultra” fabrics?

“Ultra” typically refers to a family of UHMWPE (Ultra High  Molecular Weight Polyethylene) laminates with a woven UHMWPE face fabric bonded to a waterproof film backing. Popular variants include names like Ultra 100, Ultra 200, Ultra 400, etc. The number often reflects relative face fabric density/weight. Its key components are:

• Face: Woven UHMWPE yarns (very high strength, low stretch, excellent abrasion resistance).
• Backing: A laminated waterproof film (often polyester-based) for water resistance and dimensional stability.
• Scrim or reinforcement: Some versions add scrim or extra layers for tear resistance.

Q: How are Ultra fabrics different from “Dyneema”, DCF, or Woven Dyneema?

Dyneema is a brand name for UHMWPE (Ultra High  Molecular Weight Polyethylene) fibers. Ultra fabrics use UHMWPE (a similar performance fiber) but as a woven face in a laminate. DCF (Dyneema Composite Fabric) is a nonwoven UHMWPE fiber grid sandwiched between films. Ultra uses a woven UHMWPE face plus a film backing. Woven Dyneema is similarly made but with Dyneema-branded fibers. In practice, DCF excels for the lightest waterproof shelters and ultralight stuff sacks. Ultra and Woven Dyneema shine for abrasion-heavy uses like backpacks, pockets, and pack bottoms while staying light and waterproof.

Q: Why are Ultra fabrics popular for backpacks?

• Abrasion resistance: Woven UHMWPE is extremely tough against scuffs and granite scrapes.
• Strength-to-weight: Higher tear strength per weight than many traditional nylons and some X-Pac variants.
• Waterproofness: The film backing makes pack bodies highly water resistant (seams still matter).
• Dimensional stability: Low stretch keeps packs feeling crisp and supportive.
• Ultra backpacks are available from Zpacks, Durston, ULA, and Seek Outside, among others. Many cottage ultralight backpack manufacturers use Ultra now for backpacks instead of DCF or Robic Nylon.

Q: Are Ultra fabrics used for tents?

• Less common than DCF for fly canopies because Ultra is heavier per square yard.
• Ultra may be used in high-wear and abrasion-prone tent zones: floors, corners, stake-out patches, and snow skirts.
• Tarptent sells several tents made with Ultra, including the Arc Dome 2 Ultra and the Scarp 1 Ultra.

Q: What about stuff sacks and accessories?

• Ultra is excellent for abrasion-prone storage (stake sacks, outside pockets, bear bag bags) where standard DCF might wear faster.
• For fully waterproof, ultra-light dry bags, thin DCF is often lighter; for rough handling, Ultra has better scuff resistance. In both cases, you want to make sure the seams are seam-taped and sufficiently strong to prevent water from leaking in.

Q: What weights and types of Ultra are common?

• Ultra 100/200: Lighter variants suited for pack bodies on fast-and-light builds, pockets, and reinforcement.
• Ultra 400 and higher: Heavier-duty for pack bottoms, shoulder strap anchor zones, and alpine abuse.
• Expect a range roughly comparable to 150D–400D nylon weights, but with much higher tear/abrasion resistance at the same mass.

Q: How waterproof are Ultra fabrics?

• The material is waterproof, but the waterproofness of products made with it depends on seam construction, zippers, and design.
• Some backpack manufacturers (Zpacks) seam tape their seams; others recommend a pack liner for full protection in extended rain.

Q: How do Ultra fabrics compare with X-Pac?

• Both are laminates with a waterproof film.
• X-Pac typically uses a polyester face with an X-ply reinforcement; it’s stiff and durable, widely used.
• Ultra swaps the face to woven UHMWPE, increasing abrasion and tear resistance for the weight.
• Ultra is often pricier than common X-Pac variants but can be lighter/tougher at similar performance levels.

Q: How do Ultra fabrics compare with high-tenacity nylon or Robic (which is also high tenacity nylon)?

• Nylon is cheaper, more supple, and can be very durable at higher deniers. Ultra generally offers higher tear/abrasion resistance per gram and better long-term water resistance (due to film laminate vs. PU coatings).
• Nylon coatings can break down over time; Ultra’s film backing avoids that failure mode.

Q. What are the Pros in favor of Ultra fabrics?

• Outstanding abrasion resistance for the weight.
• High tear strength and low stretch.
• Waterproof laminate backing; doesn’t absorb water.
• Holds shape well in packs.
• Good long-term durability for rough trails and off-trail use.

Q: What are the Cons of Ultra fabrics?

• Cost: Premium pricing, especially at higher weights.
• Stiff hand: Less drape and more “crisp” feel compared with nylon; can be noisy.
• Heat sensitivity: UHMWPE softens at lower temperatures than nylon; keep away from high heat sources.
• Seam complexity: Best results often require taping or careful stitching plus seam sealing; DIY can be trickier.
• Laminate failure modes: Over many years, edges and high-crease areas can show film wear or delamination if repeatedly hard-folded.

Q. Is Ultra better than DCF for packs?

Often yes. For pack bodies and pockets, Ultra’s abrasion resistance outperforms typical DCF at similar weights. Many cottage pack makers have shifted from DCF pack bodies to Ultra.

Q: Is Ultra better than DCF for tents?

No, for large canopies if your goal is minimum weight. DCF offers lower weight and very low stretch. Ultra may be chosen for floors or reinforcement patches.

Q: How does Ultra handle UV exposure?

UHMWPE fibers have good UV resistance, but laminates and adhesives can age under prolonged sun.
Practical takeaway: Trail use is fine; don’t store long-term in direct sun.

Q: Does Ultra stretch or sag when wet?

Very little. It maintains tension well and doesn’t absorb water, so weight stays consistent, rain or shine.

Q: Are Ultra backpacks truly waterproof without a rain cover?

• Pack body panels can be waterproof, but needle holes, seams, hydration ports, and zippers are entry points. Seam-taping increases the overall water resistance of Ultra packs
• A pack liner (DCF, Nylofume, or trash compactor bag) is still the most reliable option for sustained rain.

Q: How do Ultra fabrics feel compared to nylon or DCF?

• Stiffer and crisper than nylon; less “crinkly” than thin DCF but still firm.
• Slides over rock and bark without fuzzing as quickly as nylon.
• Easy to clean: dirt doesn’t embed as much as on textured nylon.

Q: What are the weight savings of Ultra compared with nylon?

• A well-designed Ultra pack can be many ounces lighter than a comparable nylon pack of the same durability.
• Expect bigger gains at the same durability level; or, at the same weight, expect a tougher product.

Q: Are Ultra fabrics noisy?

• They can rustle but are generally quieter than very thin DCF.
• Not silent like soft nylon, but most hikers find the noise a non-issue.

Q: How do I choose the right Ultra weight for a pack?

• Sub-25 lb loads, on-trail: Ultra 200 for body, heavier for bottom.
• Mixed trail/off-trail or frequent granite sits: Ultra 400 body/bottom or hybrid (200 body, 400 bottom).
• Heavy loads or alpine: Prioritize Ultra 400 on the bottom and anchor points.

Q: How do you repair Ultra fabrics in the field?

• Clean and dry the area
• Use high-quality repair tape compatible with laminates (e.g., Tenacious Tape, or brand-specific UHMWPE tape).
• Round patch corners, press firmly, and if possible, patch both sides.
• For pack bottoms with abrasion holes, a larger patch with stitched perimeter plus seam sealer is best when back home.

Q: How durable are Ultra pack bottoms?

• Significantly tougher than many nylon and DCF bottoms at comparable weight.
• Ultra 400 is comparable to Woven Dyneema
• Still, sitting backpacks on sharp rocks repeatedly will eventually wear through. Be mindful when dropping your pack.

Q: Do Ultra fabrics delaminate?

• All laminates can delaminate, given enough time and abusive creasing.
• Minimize hard, repeated folds along the same line. Roll loosely or stuff.

Q: Are Ultra fabrics breathable?

•  No. They’re waterproof laminates. Breathability in packs comes from suspension design (vents, mesh), not the fabric itself.

Q: How well does Ultra handle cold and heat?

• Cold: Stays flexible enough for normal use; slight stiffening is common.
• Heat: Keep away from hot stoves, car dashboards, or fires. UHMWPE softens/melts at lower temperatures than nylon.

Q: Are Ultra packs good for thru-hiking?

• Yes. They balance low weight with durability, especially for rocky trails and frequent set-downs.
• Many thru-hikers use Ultra packs, pairing with a waterproof liner.

Q: Can Ultra be used for hanging bear bags?

• Yes. It’s tough and lightweight. Pair it with a good cord and proper hang technique.
• For rodent resistance, no soft fabric is immune; odor control and hang discipline matter more.

Q. How does Ultra compare to Cordura?

• Cordura (a branded nylon) is very durable, especially at high deniers.
• For a given weight, Ultra tends to beat Cordura in tear/abrasion resistance.

Q: What are common failure points in Ultra backpacks?

• Stitching at anchor points, if not properly reinforced.
• Zippers and mesh pockets, not the Ultra panels themselves.
• Seam tapes at high-flex areas if poorly applied.

Q: How do you clean Ultra gear?

• Rinse dirt and salt with cool water.
• Spot clean with mild soap and a soft sponge.
• Air dry fully out of direct high heat.
• Avoid harsh solvents and machine washing.

Q: How do you store Ultra gear?

• Dry completely.
• Stuff or roll loosely to avoid hard crease lines.
• Store cool, dark, and away from sharp objects and compression weights.

Q: Is Ultra environmentally friendly?

• Ultra is a plastic-based laminate. Longevity helps reduce replacements, but end-of-life recycling is limited.
• Extend lifespan through care and repair; repurpose worn panels as organizers or stake sacks.

Q: Will Ultra make my backpack fully submersible?

• No. Most packs have needle holes, zipper paths, and openings that leak under pressure.
• If submersion is a concern (packrafting), use a dedicated dry bag liner or a pack designed for that purpose.

Q: What about condensation and breathability in shelters using Ultra?

• Ultra isn’t breathable, similar to DCF and many coated fabrics.
• Condensation behavior depends on shelter design (single vs. double wall, venting).
• Use vents, smart pitching, and keep wet gear outside the sleeping area.

Q: How do Ultra fabrics compare with siliconized polyester (silpoly) for shelters?

• Silpoly can be lighter and cheaper for large canopies than Ultra, and it’s quieter and more supple.
• Ultra beats silpoly on abrasion and tear resistance at the same weight, but it’s heavier than top-end silpoly for equal coverage.
• Tarptent was the first cottage company to use Ultra for tents.

Q: Are Ultra Backpacks overkill for weekend trips?

• If you’re budget-conscious, nylon or X-Pac may suit you fine.
• If you value durability and want to keep weight low without babying your pack, Ultra is a great choice.

Q: What’s the bottom line: Ultra vs. DCF and X-Pac for different items?

• Packs: Ultra is often the sweet spot—lighter and tougher than many X-Pac options; far tougher than DCF in abrasion zones. Ultra 400 is on par with the Woven Dyneema, now offered by Hyperlite Mountain Gear, on their most popular backpacks.
• Tents: DCF for fly canopies when weight is king; Ultra for floors and reinforcements.
• Stuff sacks: DCF for ultralight dry bags; Ultra for rough-use sacks and external pockets.

Conclusion

Ultra fabrics bring woven UHMWPE toughness to waterproof laminates, making them standout choices for backpacks and abrasion-prone gear while still being light. They don’t replace DCF for the absolute lightest tent canopies, but they beat many alternatives in pack durability at a given weight. If you want a low-weight pack that shrugs off rough trails and repeated set-downs, Ultra is one of the best options available today.

SectionHiker never accepts payment for gear reviews or editorial coverage. When you buy through affiliate links on our site, we may earn a small commission at no extra cost to you. Help us continue to test and write unsponsored and independent gear reviews, hiking and backpacking FAQs, and free hiking guides.