What Is Silnylon? The Complete Guide to This Ultralight Fabric

I've spent the last 15 years shaving ounces from my backpacking load, and silnylon has been the single biggest contributor to cutting weight without sacrificing protection.

Silnylon is a lightweight, waterproof fabric made by impregnating nylon with silicone, creating material that weighs 30-50% less than traditional coated nylons while maintaining excellent water resistance.

This fabric revolutionized ultralight backpacking when it gained popularity in the early 2000s, and it remains the go-to choice for weight-conscious backpackers, thru-hikers, and DIY gear makers.

After personally owning more than a dozen silnylon tarps and shelters, I've learned exactly where this fabric excels and where it falls short.

In this guide, I'll break down everything you need to know about silnylon from a practical perspective, not just technical specs.

What Is Silnylon Made Of?

Silnylon is short for "silicone-impregnated nylon," which means exactly what it sounds like: nylon fabric that has been infused with silicone coating.

The manufacturing process starts with ripstop nylon, a woven fabric with a grid pattern designed to stop small tears from spreading.

Silicone is then applied to both sides of the fabric, penetrating the fibers rather than just sitting on top like traditional coatings.

This creates a fabric where the waterproofing is actually part of the material structure, not just a surface layer that can peel away.

You'll find silnylon in different denier ratings, with 30D being common for tarps and shelters, and heavier 70D versions used for applications needing more durability.

Single vs. Double-Coated Silnylon

Single-sided silnylon has silicone on one side only, making it easier to tape and seam seal but less waterproof overall.

Double-sided silnylon is coated on both sides, providing superior waterproofing but requiring specialized seam sealer that can bond to the silicone surface.

In my experience, double-coated is worth the extra effort for anything that will see heavy rain.

Key Properties and Characteristics

Is Silnylon Waterproof?

Silnylon is highly waterproof, with most quality silnylon rated to withstand 2000-5000mm of water pressure (hydrostatic head rating).

This means it can handle heavy rainfall without leaking, though the actual waterproofing depends on proper seam sealing since stitching creates needle holes.

I've spent dozens of nights in silnylon tarps during thunderstorms, and the fabric itself has never failed me.

Weight and Packability

A typical 30D silnylon tarp weighs about 5-7 ounces for a 8x10 foot size, compared to 12-15 ounces for equivalent PU-coated nylon.

The stuff sack for my 8x10 silnylon tarp is roughly the size of a grapefruit, while my old poly tarp required a sack the size of a cantaloupe.

For thru-hikers counting every ounce, this difference adds up fast across a complete gear list.

Strength and Durability

Silnylon has excellent tear strength for its weight, thanks to the ripstop weave pattern that prevents small punctures from becoming catastrophic tears.

However, the lightweight nature means it's more susceptible to abrasion than heavier fabrics.

I've gotten 5+ years of regular use from my silnylon tarps, but I always use a groundsheet to protect the floor material from rocks and rough terrain.

Breathability and Condensation

Silnylon is not breathable, which means moisture can accumulate as condensation on the inside surface.

This is a common complaint from new silnylon users, who wake up to find their sleeping bag quilt damp from contact with the tarp walls.

Ventilation is absolutely critical with silnylon shelters—I've learned to pitch my tarp with enough airflow to minimize this issue.

Common Uses for Silnylon

Silnylon has become the standard material for ultralight backpacking shelters and accessories.

Tarps and Shelters

The most common use is flat tarps and shaped tarp shelters, which can weigh less than a pound while providing adequate storm protection for most conditions.

I've used silnylon tarps from 6x8 feet for solo trips up to 10x12 feet for two-person setups, and the weight savings compared to canvas or heavier synthetics is dramatic.

Rain Flies and Tent Floors

Many double-wall tents use silnylon for the rain fly because it sheds water efficiently and packs down small.

Tent floors also benefit from silnylon's waterproof properties, though manufacturers often add heavier-duty coatings to high-wear areas.

Stuff Sacks and Pack Covers

Silnylon stuff sacks weigh almost nothing while keeping gear dry, making them popular for organizing pack contents.

A silnylon pack cover typically weighs 2-4 ounces and provides excellent rain protection for your main pack.

DIY Gear Projects

The DIY community loves silnylon because it's relatively easy to work with and available by the yard for custom projects.

Common DIY builds include custom tarps, bivy sacks, hammock rain flies, and ultralight stuff sacks sized exactly for your gear.

Silnylon Pros and Cons

Advantages	Disadvantages
Extremely lightweight (30-50% lighter than alternatives)	Poor breathability causes condensation
Excellent waterproofing (2000-5000mm rating)	Lower abrasion resistance than heavier fabrics
Strong tear resistance due to ripstop weave	Requires specialized seam sealer
Compresses very small for packing	Coating can degrade from UV exposure
Relatively affordable compared to Dyneema	Slippery texture makes sewing difficult
Widely available for DIY projects	Can stretch when wet, affecting pitch stability

Where Silnylon Excels?

Silnylon shines in weight-critical applications like thru-hiking, alpine climbing, and any situation where every ounce matters.

For fair-weather backpacking in areas with typical rainfall, a silnylon tarp provides more than enough protection at a fraction of the weight of traditional shelters.

My Appalachian Trail thru-hike used a silnylon tarp for the entire 2,190 miles, and I never regretted the weight savings.

Where Silnylon Falls Short?

Above treeline in exposed terrain, I've seen silnylon tarps struggle with wind-driven rain that finds its way through microscopic pinholes in stressed fabric.

For desert camping with intense UV exposure, the silicone coating can degrade faster than in forested environments.

If you're setting up camp on abrasive surfaces like granite or sandstone, silnylon requires a groundsheet or you'll wear through it in a single season.

Silnylon vs Alternative Fabrics

Fabric	Weight (oz/sq yd)	Waterproof	Durability	Typical Cost
Silnylon (30D)	0.9-1.2	Excellent	Moderate	$
PU-Coated Nylon (70D)	2.0-2.5	Excellent	Good	$
Ripstop Nylon (uncoated)	1.5-2.0	Poor	Good	$
Dyneema Composite Fabric	0.6-0.9	Excellent	Excellent	$$$
Polyester (coated)	2.0-3.0	Good	Good	$

Silnylon vs Cuben Fiber (Dyneema)

Dyneema Composite Fabric (formerly Cuben Fiber) is significantly lighter and stronger than silnylon, but costs 4-5 times as much.

For most backpackers, silnylon offers 80% of the performance at 20% of the price.

I've used both, and unless you're attempting a FKT (fastest known time) or counting grams for an alpine push, silnylon provides better value.

Silnylon vs PU-Coated Nylon

Polyurethane-coated nylon is heavier but more durable and doesn't require special seam sealer.

For car camping or shorter trips where weight isn't critical, PU-coated nylon may be the better choice.

My family camping tent uses PU-coated nylon because durability matters more than weight when I'm not carrying it on my back.

How to Care for Silnylon Gear?

Cleaning Silnylon

Hand wash silnylon in cool water with mild soap if it becomes dirty or stained.

Avoid machine washing, which can damage the silicone coating and stress seam tape.

I rinse my tarp in a lake or stream when backpacking, then air dry it completely before packing.

Seam Sealing Silnylon

New silnylon gear requires seam sealing at needle holes, using silicone-based seam sealer specifically designed for silnylon.

1. Clean the seam area with rubbing alcohol
2. Apply seam sealer thinly to the inside of all stitched seams
3. Let dry for 24 hours before exposing to moisture

I recommend sealing seams even on factory-seamed gear, as manufacturers sometimes miss spots or apply sealer too thinly.

Storage and Long-Term Care

Store silnylon loosely folded or hung, not compressed in a stuff sack for long periods.

UV exposure degrades silicone over time, so don't leave silnylon gear set up in direct sunlight when not in use.

My oldest silnylon tarp is 8 years old and still waterproof because I store it properly and avoid prolonged sun exposure.

Repairing Silnylon

Small holes can be patched with silicone repair tape like Tenacious Tape or specialized silnylon patch kits.

For tears, use a needle and thread to close the gap first, then apply a patch on both sides.

I've successfully repaired minor damage from tree branches and campsite mishaps using this method, extending the life of gear by years.

Frequently Asked Questions

Final Thoughts on Silnylon

Silnylon remains one of the best fabric choices for ultralight backpacking in 2026, offering an excellent balance of weight, waterproofing, and affordability.

After thousands of trail miles using silnylon gear, I can confidently recommend it for anyone looking to reduce pack weight without sacrificing weather protection.

The key is understanding its limitations—poor breathability, moderate durability, and the need for proper seam sealing—and choosing applications where its strengths shine.

Whether you buy ready-made silnylon gear or try DIY projects, this fabric has earned its place in the ultralight hall of fame.