The Use Of Silnylon: How Do You Know How Waterproof Your Tent Is?

Everyone is talking about Silnylon, so what is it? Silnylon is a blend of the words "silicone" and "nylon," most technical people prefer the name siliconized nylon. It is a synthetic waterproof fabric that is highly used for outdoor gear such as parachutes, hot air balloons, tents, rain jackets, etc. Whenever people talk about silnylon, they mean siliconized nylon. It is made by soaking a fragile knitted nylon fabric combined with liquid silicone from both edges of each side.

What’s Silnylon good for?

Most small, specialized manufacturers used this item for creating "ultralight" backpacking gear or expedition-grade tents, some of which sold it for DIY-ers for customers, clients, and people who love to make their camping tents and tarp shelters.


When we talk about waterproofing, we must know and understand how waterproofing is measured. Waterproofing is well measured using the hydrostatic head test. The hydrostatic head test measures the amount of water pressure a fabric can withstand even before the water starts to pump through it. A circular tube with steel known as the "column" added with water is placed over the fabric. The more water added to the circular tube, the more pressure will be added to the material. When droplets of water begin to dip through the fabric, the height of the column will be measured in millimeters. These measurements will be translated into data making the waterproof rating of the material.

 (Featherstone UL Granite 2P being tested in the Lab)

Not all tents are covered

Although the waterproof rating of silnylon is informative and valuable for your decision-making, silnylon tents may still leak at their joints or "seams" (unless it is seam-sealed with silicone.) Most manufacturers that offer silnylon tents cover seam-sealing services for your tent (if the tent is not seam-sealed); this service could cost extra and increase your tent's weight by an ounce or two. Remember to ask your seller first what kind of tent you want before buying.

The comparison of different tents measuring their waterproofness (measured using the hydrostatic head)

If silnylon fabrics are produced to make tents, many companies separate waterproof treatment on the rain fly(top of the tent) and floor(ground of the tent) because the floor most often has a higher pressure than the fly.

The outcome could look like this:


Rain fly



Big Agnes Copper Spur HV UL 2



Sil/PU Nylon

MSR Hubba Hubba NX2



Sil/PU Nylon

Durston/Drop X-Mid 1

2,000 mm

2,000 mm

Sil/PU Polyester

Featherstone UL Granite 2P



Sil/PU Nylon


In summary, silnylon is a helpful fabric used in many products; it's also suitable for tents, providing a waterproof attribute comforting you through rainy seasons. Waterproofness is measured using the hydrostatic head. Silnylon tents may still have a waterproof cover to seams unless it is sealed and covered with silicone, but most manufacturers offer seam-sealing services to cover these leaks, which could cost more money and add more weight to your travel. 


Back to blog

Leave a comment

Please note, comments need to be approved before they are published.