by ExPo Staff

After sleeping in a tent for 45 nights straight, one gets accustomed to noticing the differences between brands, the hardware, the mattress, the hinges, the ladders; but more than anything else you get to be an expert on fabrics.

There is an array of fabrics available to rooftop tent manufacturers. We see everything from rip-stop nylon, poly-cotton blends, to proprietary fabrics used on tents. As consumers, we need to know how fabric choice will affect weight, durability, breathability, water resistance, strength, and the cost of a tent. When you start shopping for your roof top tent, these are some of the fabric qualities to keep in mind:

  • Cotton – 100% cotton fibers are fully breathable, extremely durable and abrasion resistant. As the thickness of the cotton increases, the breathability decreases and with added thickness comes added weight. Cotton absorbs moisture, and any natural water resistance is a result of swelling and tightening of the material weave.
  • Polyester – 100% polyester fibers are light, strong and tend not to stretch. A tent made from polyester has a natural water resistance, is quick to dry, and is tear resistant due to its elasticity. Polyester does not, however, breathe, and it is not very abrasion resistant.
  • Poly-Cotton – These blends combine the strengths of both cotton and polyester fibers and tend to be breathable, tear-resistant, and abrasion resistant.
  • Rip-Stop Nylon – Most rip-stop nylon fabrics are poly cotton blends with nylon threads in crosshatch patterns used to reinforce the material against tearing. The fabric exhibits the same qualities as poly-cotton with additional strength to resist tearing.
  • Proprietary Fabric – Autohome produces its own proprietary fabrics that are acrylic-cotton blends. Acrylic is a good choice to blend with cotton because it is resistant to oils, chemicals, and to deterioration from UV. It produces a soft fabric with the feel of cotton and it does not absorb moisture.
  • Nylon – This has the strength, flexibility, ease of drying, water resistance, and abrasion resistance that we are looking for in a fabric. It can also be woven to produce a breathable fabric and treated for UV resistant. Unfortunately we haven’t seen any of these qualities in nylon fabric used on roof top tents. The breathability seems to be compromised by a thin film of silicon to enhance waterproofing, and the tent fabric looses its integrity around the 5-year mark due to exposure to UV.

    Top quality roof top tents, like the Eezi Awn, are made from core spun poly-cotton. The threads have a central core of polyester with cotton spun around it. The polyester portion gives the thread strength and prevents the fabric from stretching, and the cotton portion gives the absorbent and breathable qualities so necessary for comfort. Typical poly-cotton blends are 65% cotton and 35% polyester.

    The art is to produce a material that is strong, breathable, and has the softness of cotton. As the cotton portion of poly-cotton is highly absorbent, the manufacturer can immerse or spray the fabric with various solutions to provide color, UV resistance, mold protection, and water resistance. The process provides these qualities to all of the material rather than the more common and less expansive method of the coating being applied just to one side of the material.

    Synthetic tents typically have surface treatments that are used to enhance the sealing of the fabric and provide UV protection. The issue with surface treatments is that they inhibit breathability and you have to rely on windows and vents to get an exchange of air between the outside and the inside of the tent.

    We are often asked why we prefer to use tent fabrics that are water resistant instead of being waterproof. The answer has to do with the breathability of the material. Waterproof tents produce a very unpleasant musky micro-climate inside the tent. We want an exchange of gases and vapors between the interior of the tent and the exterior, while at the same time keeping the water droplets outside the tent. As breathability increases, waterproof qualities decrease, and as waterproof qualities increase, breathability decreases. The trick is to find the right blend of both.

    Poly-cotton has very high resistance to abrasion. Being core spun, the exterior cotton fibers are smooth, giving the material a soft feel. When a tent made of poly cotton is folded away, the smoothness of the fabric creates very little friction or wear between the layers. In contrast, pure synthetic fabrics have coarse fibers and exhibit strong abrasive qualities. Your tent material should be selected for its low abrasion qualities, and its strength to resist the abrasion.

    The quality of poly cotton fabric varies depends on the balance between polyester and cotton, where it was milled, and what additives are used to enhance its qualities. Fabric used by Eezi Awn and the Advanced Technologies fabric, used by AT on their JK Habitat, are produced by mills that not only weave the material but also treat the material in house for UV stability, waterproofing, and anti-mold. Because the mills see the fabric through from start to finish, they have control over the whole process, so their fabrics are more consistent and reliable. Like hand crafted beers or estate-bottled wines these fabrics are more costly to produce, but the quality and camping experience justifies the expense.

    The weight difference between fabrics is minimal, a matter of a few pounds or kilos. Tents we recommend have fabric weights of around 380g/sq.m (about the same thickness and weight as a pair of Carhartt work pants). Our experience has been that the heavier materials show excellent breathability and water resistance, low abrasion, and high durability. When you look at a 380g/sq.m treated fabric you’ll find that at least 70g/sq.m of the weight comes from the immersion treatments mentioned earlier. Lighter weight fabrics tend to be less well treated and don’t exhibit the breathability, abrasion resistance, and durability of the heavier fabrics.

    Windows and doors should be covered in mosquito netting as a barrier to insects. Eezi Awn uses a fine meshed shade cloth as netting while other companies use polyester netting. Both work for keeping mosquitoes and most other insects at bay. The shade cloth netting is stronger and more durable than the standard netting.

    No-see-ums, the tiny biting flies, present unique challenges. Standard mosquito netting has 270 holes per sq/inch and an 80% airflow rating, where as netting for no-see-ums has 800 holes per sq/inch and a 65% airflow rating. We haven’t seen a roof top tent fitted with the ultra-fine netting needed to keep no-see-ums out. If you camp frequently in areas with no-see-ums then making custom nets may be the best answer, although it will severely restrict the flow of air through the tent. For those who experience no-see-ums only on occasion the best practical solution is to spray the netting with “Skin So Soft” or a regular insect repellant.

    Stitching only makes up a small portion of the tent, but it’s crucial to the tent structure. Poly-cotton thread has what is called in the trade “maximum sewability”; in other words it’s less likely to have a malfunction on the sewing machine, and it stands up to wear and tear over time. When we fit tents to trailers and vehicles, part of our inspection is to check every seam for integrity. Our experience over the years has been that all the tents that are made in-house show very few stitching errors; technically and esthetically the stitching is perfect. Where we see problems is with stitching done by third parties. We see on a consistent basis:

  • Seams that are not straight
  • Seams where two pieces of material join and one of the sections is not attached
  • Mosquito netting not completely sewn onto the adjoining fabric
  • Stitching that has started to unravel
  • Loose pieces of thread hanging from the fabric
  • Seams are stopped and re-started in the middle of what should be a single seam
  • Single stitching used where double stitching should have been used
  • Frayed material at seams that should have been hemmed under
  • Care of your tent:

    When you first get a poly-cotton tent it’s always a good practice to lightly spray the tent fabric with a gentle shower of water from a garden hose. This will allow the cotton portion of the thread in the weave and stitching to absorb the moisture and swell up. This does two things, it tightens the weave of the fabric, and it also swells the stitching to fill the hole created by the needle.

    When the fabric is sewn together the thread that is used is also poly-cotton, and because it has the ability to absorb liquid, when it does it increases in diameter and fills the hole created by the sewing needle. It’s important that the sewing machine has been fitted with a needle that is the same diameter as the thread to create a watertight seam. On occasion the stitching will weep moisture through the seam. The simplest solution for this is to rub some bees wax along the seam to seal it.

    If your tent is fitted with a coated poly-cotton flysheet, follow the same wetting procedure. Even though the flysheet is coated, the poly-cotton and can absorb water into the weave and the stitching.

    Keeping your tent clean:

    Roof top tents stay remarkably dirt free in comparison to ground tents. The elevation keeps them up away from mud splatters, grass, and grime, as well as the ground winds that blow dust and debris around. But they do need to be kept clean.

    The best way to do this is to take a hand brush and brush down the fabric to get rid of any surface dust or dirt. It’s a quick process and only takes a few minutes. Lots of people clean their tents in camp before packing them away. The material has to be dry when you brush it off. If you want to clean the tent at home you can vacuum the material using a soft brush accessory.

    Dirt on the fabric can shorten the life of a tent due to added abrasion. When folded away, the material layers rest against material layers, and the movement of the vehicle results in the fabric rubbing against itself. If there is a layer of dirt on the material it can act like sand paper and cause the material to wear.

    If the tent material is damp when you pack the tent away, it should be opened up at the next opportunity to allow it to air out and dry. This will prevent any mold or mildew growing on the tent and help preserve the material.

    Many of us remove our tents when not in use or over the winter and store them in our garage or shed. I have to take mine off and store it against the wall of the garage. Before I remove the tent I make sure it’s dry, the tent is neatly folded away, and the cover is on correctly. I then place it on edge on a couple of blocks of wood so it’s off the floor. So long as it remains dry and the mice don’t get into it, you are good to go.

    When you are looking for a roof top tent, select one that uses quality fabric and materials. If you have the opportunity, climb into one and zip all the windows and doors closed. If it starts to smell musky after five minutes the material doesn’t breathe well. Lay back on the mattress and start looking at the stitching and hardware. Does the tent have the look and feel of something that will provide you with 20 years of service?

    >p>Adventure Trailers (AT) has been fitting roof top tents to trailers and vehicles since 2001. We have fitted all the big names including Eezi Awn, Autohome, Hannibal, and some less well-known brands like MyWay, Karoo, and Cristy. In recent years we have fitted the ARB tents and branded Chinese manufactured tents.

    Martyn Davies is the co-founder of Adventure Trailers

    AT is the designer, manufacturer, and purveyor of innovative high-end equipment for vehicle based expeditions and remote campers. We provide shelter, comfort, and convenience through our durable unique products.

    http://www.adventuretrailers.com/

    Rooftop Tent Fabrics and Care

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    About the Author: ExPo Staff