Plastic sheeting, otherwise known as polyethylene or poly sheeting, is a surprisingly complex material. Not all poly sheeting can be used interchangeably. Rolls of plastic sheeting come in different colors, thicknesses, and even chemical compositions. In some cases, using the wrong kind may have disastrous consequences! Before you leap headfirst into construction or agricultural projects with just any kind of plastic sheeting at the ready, be sure that you understand which type you really need to get the job done right and safely.
First thing’s first: what environmental concerns might you need to address? Since the chemical formula for polyethylene is quite malleable, many varying compositions of the material exist. This means different types of poly sheeting have unique chemical additives making them better suited to specific applications. For example, it is possible for poly sheeting to become flame retardant with the additive ASFR-6. Without a flame retardant additive, however, a roll of plastic will (unsurprisingly) go up in flames in no time! Other kinds of plastic sheeting are UV resistant and will hold up well in the sun. Non-UV-resistant plastic film will do very little to protect what is underneath from harsh ultraviolet exposure. Another consideration for chemical makeup has to do with food safety. In order to make sure plastic sheeting is food grade, you must be sure it is made of 100% virgin polyethylene. Plastic sheeting that does not have 100% virgin polyethylene makeup has a less stable formula, which can lead to chemical leaching. This can be very dangerous if the poly sheeting is being used as food packaging or as a pond liner. Another useful additive makes certain types of plastic sheeting self-adhesive, meaning it will stick to certain surfaces on its own. This is particularly useful for protecting counters, carpeting, and floors during painting projects. For projects that require specific additives, please inquire with your salesperson to ensure that you are getting the right product for you.
Next: consider what threats to the polyethylene will exist while in use. Will the plastic sheeting be exposed to harsh weather conditions or animals? Is it meant to be torn open as food packaging? You will want to choose the thickness and strength of your sheeting accordingly. The thickness of poly sheeting is measured in thousandths of an inch, or mils. The higher the number, the thicker the sheeting. Here at CWC, our polyethylene sheeting comes in thicknesses ranging from below 1mil up to 10 mils. Anything 2mil or below is generally intended for temporary protective purposes. Food packaging is usually below 1mil, while sheeting meant to drape over furniture during painting projects will be about 2mil. For protecting counters and floors, 3mil self-adhesive film typically does the trick. (For reference, at 3mil, the thickness of the poly sheeting is about as thick as a shopping bag.) You will want to double that thickness to at least 6mil for heavier duty projects such as construction enclosures, temporary erosion control, vapor retardants, or greenhouse coverings. If your projects must withstand harsh weather, animals, or simply just needs to last a while, you may need to get something stronger up to 10 mils.
Now that you’ve figured out what kinds of chemical and physical protection your poly sheeting requires, how do you decide which color to get? Typically, plastic sheeting comes in either black or transparent variations, but which one is the best one for you? Well, the answer can be a bit tricky. It depends on the climate of your location– (not just weather, but humidity/moisture levels and temperature) and the specific needs of your project. For clarity’s sake, I will be splitting this section into two industries you are most likely to use plastic sheeting in, agriculture and construction.
In agriculture, plastic sheeting is often used in greenhouse roofing, plant protection, and weed killing. For the first two, you almost always want to use clear plastic sheeting. Transparent plastic traps moisture and heat and allows for light to pass through to promote growth in moist environments. When it comes to weed killing, the answer varies. Black plastic blocks out light and provides an excellent moisture barrier. If you live in a particularly humid environment, such as the deep south, black plastic sheeting is quite useful for occultation. Clear plastic, on the other hand, is good for solarization in drier climates. Occultation and Solarization are both pesticide-free weed and pest killing and repellent methods that involve covering a large strip of land with plastic sheeting and securing it to the ground for at least six weeks. You should use black plastic sheeting for occultation in the warmest season if you live in a very hot, humid location. Use clear plastic sheeting for solarization during the hottest season if your area has a dry climate. It is worthwhile to note that since black plastic absorbs sunlight, it will most likely never get hot enough underneath to eradicate pathogens. This is not an issue with solarization.
In construction, the color of the plastic sheeting used depends on where it is being used in the project. When it comes to indoor insulation projects such as vapor retardants and moisture barriers, you can rest easy knowing that the color of poly sheeting you use will not matter. Typically for barriers and coverings, clear plastic sheeting (around 4 mils thickness or above) should be used. This protects against dust and debris while allowing for higher visibility. When it comes to protecting goods and equipment that are being exposed to the elements, the most important factor to consider is a UV-resistant additive and a higher thickness. Both black and clear poly sheeting can have these.
In conclusion, choosing the correct plastic sheeting for your specific application is essential to ensure the success of your projects. Be sure to consider the chemical makeup, thickness, and color of the sheeting you need thoroughly before you begin. As always, if you are ever in doubt, our CWC product experts are here to help!
written By Zachary Miller
CWC product expert
Last Modified: 03/07/2022