What should you be looking for when buying a canopy? The first thing to decide is what the canopy will be used for. Often, a canopy is serving outdoors as a portable garage or a portable shed, but other uses for a canopy tarp include use as a roof patch or an outdoor shade canopy. And, in the case that a canopy will be using to shade people, it should also meet certain requirements and standards.
For the basic canopy for a portable garage, the basic material is heavy duty polyethylene. What constitutes a heavy duty poly tarp? A heavy duty poly tarp, as it will be used outdoors for a long period of time, should weigh six ounces per square yard and have a 12 mil. thickness, 14×14 mesh count, as 1200 denier. When used with a powder coated or galvanized steel frame, the tarp needs to have grommets, spaced every twelve inches, which can be attached to the frame with bungee cords.
Aside from the physical composition, a canopy needs to have additional properties to keep it in shape when outdoors for long periods of time. These are weather resistant properties that result from treating a tarp on one or both sides with chemicals or other protective substances. A label for a heavy duty tarp, for outdoor use, should be 100-percent UV resistant on one or both sides, tear resistant, waterproof, rot resistant, and mildew proof. In some cases, as when a tarp or canopy structure is protecting a boat or RV for at least six months, the waterproof, rot resistance, and mildew resistance are particularly important for protecting the vehicle to ensure its continued use. Other weather resistant properties a tarp should have include arctic flexibility for cold temperatures and fire resistance. For the latter, a canopy tarp should be NFPA 701, CPAI 84-7, and California Title 19 certified.
Not all tarps are heavy duty polyethylene, however, and in some cases, such as for a shade or garden canopy or a roof patch, a temporary tarp can be used, such as a blue tarp for a hurricane. A medium duty tarp, such as a blue tarp, is one example of a temporary tarp which, although treated to have the same weather resistance, the composition of the tarp is 4.5 ounces per square yard and has a 6 mil. thickness, 10×10 mesh count, and 900 denier. Another option for outdoor structures also includes mesh tarps which, although with the same properties, are made of polypropylene and allow light into the canopy shelter in a 73 shade/27 light ratio.
