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SilPoly

SilPoly is a ripstop polyester with a silicone-based coating on at least one side. Our primary tarp and rainfly fabric is a 20D recycled ripstop polyester with silicone on both sides. For extra weight savings, we also offer some tarps in a 15D SilPoly. We similarly use 20D SilPoly for nearly all of our floors, with multiple coating options to provide different characteristics.

Coating Options

We use three types of coatings across our products.

Sil/Sil: silicone-based blend on both sides. This is our standard coating for tarps and is available for the floor material on select shelters. It's proven and reliable, but requires seam sealing, which we offer as an optional service. As a floor, Sil/Sil is the lightest option and a good fit if you plan to use a groundsheet, though using one is not usually necessary. Available for our 1P Swiftline and 1P Cirriform SW.

Sil/PeU: silicone-based on the outside, polyether urethane on the inside. We use this for the floors of our Bug Bivy, 1P Bug Shelter, and 1P Cirriform DW. A little less slippery than a Sil/Sil floor. The PeU backing allows for factory seam taping and easy field repairs with common patches and repair tape.

Sil/PU: silicone-based on the face, polyurethane on the back. The least slippery of our floor options, with the best water and puncture resistance (even better than the 40D SilPoly Sil/Sil that we've previously offered). A good choice if you want maximum floor protection and don't want to carry a groundsheet, but it's also the heaviest. Available for our 2P Bug Shelter, 1P Swiftline, 1P Cirriform SW, and Tub Floor.

SilPoly Advantages

• Lower price than DCF
• Won't sag when it rains and the temps drop
• Polyester is hydrophobic, meaning it has less water retention
• Holds up to UV better than nylon
• Lower stretch than our SilNylon
• Compresses smaller than DCF
• Generally lower environmental impact than nylon, with greater potential for recycling
• Most of our SilPoly fabrics use 100% recycled yarn

SilPoly Disadvantages

• Typically has a lower tear strength compared to equivalent-weight nylon
• Requires seam sealing

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SilNylon

We're not currently using SilNylon. The following refers to the SilNylon we formerly offered and is kept here because it's the material most commonly compared against SilPoly.

Our SilNylon was a 30D ripstop Nylon 6.6 with a silicone coating. It weighed 1.1 oz/yd² prior to coating and about 1.3 oz after. We used it for both tarps and floors. Nylon 6.6 is stronger than the more common Nylon 6.

Advantages

• Lower price than DCF
• Higher tear strength than equivalent-weight polyester
• Compresses smaller than DCF

Disadvantages

• Degrades faster in UV than polyester
• Requires seam sealing
• Hydrophilic; retains more water than polyester
• Relaxes and sags when it rains and the temperature drops
• Typically more environmentally impactful than polyester, and more difficult to recycle

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DCF

We've phased out DCF for our tarps to focus on SilPoly. DCF is currently available for select floors; the Y-Zip Bug Bivy is the only current product with a DCF floor option.

Formerly known as "cuben fiber," DCF (Dyneema® Composite Fabric) is a nonwoven laminate of UHMWPE yarns sandwiched between two polyester films. Our current DCF floor uses a 0.67 oz/yd² variant (CT1E.08/K.18). We previously offered a 1.0 oz/yd² variant (CT2K.18) for floors and may offer it again.

When we offered DCF for rainflys and tarps, we primarily used the 0.8 oz/yd² variant (CT2E.08). We've also worked with a 0.51 oz/yd² variant (CT1E.08), which is more common among other manufacturers. While the 0.51 oz material is a solid option, the 0.8 oz lasts significantly longer and is much stronger, due to a higher density of UHMWPE yarns. We chose the 0.8 oz as our default to reduce overall waste and deliver a better long-term performance.

Advantages as a Tarp

• Very strong for the weight
• High waterproofness
• Very low stretch helps shed wind
• No sag; won't sag when it rains and the temperature drops
• Does not require seam sealing

Disadvantages as a Tarp

• High price
• Louder when it rains
• Low stretch means a tighter pitch sweet spot, with less flexibility in adjusting the shape of your pitch
• Less compressible than SilPoly, though the 0.67 oz variant packs down quite small

As a floor

The stretch, noise, and pitch considerations above apply to tarps. For floors, the main advantages are no seam sealing required, factory-taped seams, and easy patching and repairs. The 0.67 oz variant is very packable; the 1.0 oz DCF not so much.

The two variants differ in meaningful ways. The 0.67 oz has the same yarn density as the 0.51 oz material; the 1.0 oz shares its yarn density with the 0.8 oz. The 0.67 oz compensates with a thicker outer film: it matches the 1.0 oz on the face, which is where abrasion resistance matters most. The inner film is thinner, matching the 0.8 oz, which matters less on that side.

We tested both around 2017 by sending a floor split down the middle, half 0.67 oz and half 1.0 oz, on a PCT thru-hike without a groundsheet. The 0.67 oz section developed tiny holes about halfway to two-thirds through the trail; the 1.0 oz was still going strong at the end. Our take: the 0.67 oz is a strong choice for more intermittent use or if you plan to use something like a polycro groundsheet underneath. 1.0 oz is better for heavy use without a groundsheet.