Red Sky Shelters is committed to offering materials that yield the best performance, durability and safety with the least environmental impact. Close to a decade ago we phased out the use of PVC-coated fabrics for our Yome coverings. This decision left us with very few options and we have had to pioneer and develop our own alternative materials. From our silicone Legacy roof fabric to our new Frontier 100% hemp sidewall fabric, we have developed a set of fabric options that are suitably durable and functional yet environmentally friendly.
is PVC, and whats wrong with it?
PVC stands for polyvinyl chloride, commonly known as vinyl. It is one of the most commonly used plastics in the world. Unfortunately, it’s also one of the worst products for the environment. Every step in the life cycle of PVC is riddled with serious environmental and health concerns. This is why Red Sky Shelters, unlike nearly every other portable shelter manufacturer, has eliminated the use of PVC-coated fabric in its products.
When PVC is produced, many of its basic constituents (including ethylene dichloride and vinyl chloride) are released into the atmosphere. These are considered to be not only carcinogenic but also to cause liver, kidney and neurological damage. Workers in vinyl plants have become ill from exposure to these toxic compounds.
PVC manufacturing plants also create significant amounts of dioxins and PCBs, and these frequently leach into the groundwater. In fact, sediment samples taken downstream from these plants have shown dioxin concentrations equal to that of Agent Orange! See PVC Bad News in Threes and Polyvinyl Chloride .
Even more problems are created when PVC is used as a fabric coating. This is because PVC is normally a rigid substance. In order to make it flexible, plasticizers are added. Over time, these plasticizers leach to the surface and are released into the air. This is the off-gassing commonly recognized as the “vinyl odor” in shower curtains and children’s toys. Studies indicate that there are health concerns associated with these plasticizers as well. See Our Stolen Future and My House is Your House.
It is possible to add a final coat to PVC-coated fabrics, sealing in the plasticizers. This is often done on exterior surfaces for added durability and cleanability. However, the interior surface is typically lacks this top coating, forcing the plasticizers to off-gas into the interior. This is a significant problem in living spaces. Sealing the interior surface helps, but this only addresses one of the many health and environmental problems associated with PVC.
Claims are made that PVC coated fabric can be recycled. However, trying to recycle it causes even more problems and requires more energy than what it would take to landfill it and make more from scratch. Should it be incinerated or burned, PVC releases several extremely toxic substances including dioxin.
Despite these drawbacks, other yurt and dome manufacturers use vinyl-coated fabric almost exclusively. And not only is the roof PVC: Though few manufacturers will call attention to it, the sidewalls are PVC-coated as well. Yurts and domes are considered “alternative” living structures, yet they are completely coated in one of the most ubiquitous and environmentally-destructive substances known. Note that when other manufactures call their fabric “resin-finished” or “acrylic top-coated,” they’re not admitting that these are only the top-coats and most of the material is PVC.
From production to consumption to disposal, vinyl raises serious health and environmental concerns. You can count on Red Sky to be aware of these concerns and always choose the best materials for your health and that of the planet.
are the alternatives to vinyl-coated fabric?
most common alternatives to PVC are urethane, acrylic, olefin, PTFE (teflon),
and silicone. Though none are as harmful as PVC, each of these materials one
has its own set of environmental impacts. See our Architectural
What about the Yome’s windows? Aren’t they made of PVC?
Yes, the clear removable covering for our standard windows is vinyl, but we do also offer a polycarbonate alternative. It has greater optical clarity and a longer lifespan. However, polycarbonate windows are several times the cost of PVC. They also cannot be rolled up like vinyl. In hot weather, they can be removed and stored in a cloth container provided.
What roof fabrics does Red Sky Shelters use for the Yome?
Our standard roof material is our Legacy silicone-coated polyester roof covering. For do-it-yourselfers, we offer our Voyager ceramic-acrylic based roof coating, to be applied by the Yome owner.
What is silicone?
Silicone is a polymer made from silicon, oxygen, and various organic compounds. Silicone is unaffected by ultraviolet radiation, oxygen, ozone, or high temperature - all these agents that degrade most other polymers. Furthermore, silicone filters out harmful UV-B rays, the type of UV rays that damages materials including our skin.
As far as we know, pure silicone is a completely environmentally “green” substance. Not only is silicon the most abundant mineral on earth, but throughout silicone’s life cycle, from its manufacturing to its disposal, no harmful byproducts are produced. Unlike PVC, silicone when burned (at high temperature, given its high flame resistance) produces merely an ash of silica dioxide, a.k.a., sand.
If silicone is “green,” why does it have a bad environmental reputation?
It is possible to dilute silicone rubber in its liquid state with solvents. Years ago, in many processes involving silicone, these solvents were allowed to escape into the environment. It was these solvents that cause environmental concern. Although there are now solvent recovery systems, these are technically-complicated and it is not necessary to use solvents at all when coating with silicone. We use only solvent-free silicone with 100% rubber solids to coat onto our roof fabric .
What is your silicone-coated Legacy roof material?
For our Legacy roof material, we start with an extremely tough, plied-polyester base fabric (the same fabric used for conveyor belts) and incorporate a newly developed, environmentally-sensitive, flame–resistant compound. We then bond a heavy layer of silicone rubber to the exterior and our ceramic-acrylic coating (see below) on the interior. The result is an extremely durable and strong material that keeps the weather out. This material will out-perform any PVC-coated architectural fabric in its class in strength, tear-resistance and longevity.
If silicone coated fabric makes such a great architectural material, why isn’t it used more often?
Good question! The main answer is probably the cost. Silicone coating is 5-6 times more expensive than PVC coating. However, if PVC’s true environmental cost were factored in, silicone would be considered a bargain.
What about the Voyager ceramic-acrylic-coated roof?
This is a do-it-yourself option for Yome kits. We start with a roof material made out of Sunforger-treated polyester-cotton fabric. Upon setting up the roof frame on the ground, two coats of Voyager ceramic-acrylic coating are applied to the roof by the Yome owner. This coating not only seals and protects the roof but also provides some insulation. Millions of tiny hollow ceramic beads suspended in the coating give it a hard yet flexible weather-resistant finish, one that forms an insulating radiant barrier.
What is the ceramic-acrylic coating made of?
Our ceramic-acrylic coating is an engineered combination of solar-reflective ceramics suspended in a hybrid emulsion of acrylic resins in water. This low VOC reflective coating incorporates top quality elastomeric polymers and unique ceramics that have been recycled from fly ash.
How does the ceramic-acrylic coating insulate the roof?
The coating on our Voyager roof fabric has suspended in it tiny ceramic spheres only slightly thicker than a human hair. These balls have walls only 1/10 of their diameter, yet they are amazingly strong, with a compressive strength of over 6000 psi. Obviously fire-proof, they are chemically-resistant as well.
When applied onto our roof fabric, these ceramic beads nestle together as the water and other vehicles evaporate, creating a tightly packed, hard yet flexible thermal barrier, one that reflects much of the radiant energy that shines down on it or tries to escape from inside.
Do you have to coat the Sunforger-treated fabric in the do-it-yourself kit with the ceramic-acrylic sealant?
No, in dryer environments it is not necessary. Sunforger-treated fabric is already both water and mildew resistant and has been used for years in camping tents and tipis. However, in wetter environments which experience a lot of rain or snowfall, we recommend applying the ceramic-acrylic coating. It not only seals the roof but also extends the life of the material.
Why can’t you offer a silicone coating that can be applied by the customer for Yome kits?
The process silicone requires isn’t really suitable to be applied by the customer. While the ceramic-acrylic coating can be brushed on like thick paint and will air dry, silicone is a liquid rubber that requires a unique and controlled application and curing process, so much so that we don’t do it ourselves in-house; we have it done for us .
What sidewall fabrics do you offer?
Sunforger is our standard wall fabric. We also offer Sunglow, our acrylic-coated option, and Frontier, our premium hemp fabric. All three materials are fire, water, and mildew-resistant. Our Sunforger and Frontier fabrics are both breathable, and all three are translucent. Their natural color allows filtered light to enter and bathe the Yome in a rich and elegant glow. It’s like living in a cloud !
What is your Sunforger wall fabric made of?
Our standard sidewall fabric is a Sunforger-treated heavy cotton canvas. The Sunforger treatment (formerly known as Vivitex) has been used for decades and has proven itself to be a utilitarian material that offers great value. Water and mildew-resistant, it has a 3-10 year lifespan, holding up longer in dryer conditions than wetter ones. The fabric’s natural off-white color changes somewhat unevenly over time, but this does not affect its lifespan. We add an environmentally-friendly fire-resistance treatment to make our sidewall material safe.
What’s special about your Frontier hemp sidewalls?
Hemp is not only very environmentally-friendly, it has a number of amazing properties that make it an ideal sidewall material. The chief disadvantages of hemp is that it is naturally neither fire nor water-resistant. However, by tightly weaving the hemp in a twill pattern, we’ve achieved a fabric that is quite water-resistant. A durable, environmentally-friendly, non-halogenated treatment renders it flame-resistant. The resulting fabric, with its natural unbleached light beige color, will last a long time.
What about your SunGlow sidewall option?
Our other premium sidewall option is an acrylic-coated polyester material. Off-white in color, it is comparable in weight and feel to PVC-coated fabric, yet it is completely PVC-free . Being completely synthetic yet also flame-resistant, SunGlow does not breathe like our other alternatives, but it is more mildew-resistant and very cleanable, making it a good choice for high moisture conditions.