How to Calculate the Thickness of Plastic Sheeting

Today's plastic sheeting can be used for all types of applications, from greenhouse coverings to garden mulch and even as a temporary shelter from adverse weather. Plastic sheeting is not only rated by the type of plastic and sunlight resistance but also by the thickness. By understanding some terminology, you can calculate the thickness of a plastic by reading the box label.

Difficulty: Easy

Instructions

1. Understand that all plastic sheeting is rated in thickness by the term of the mil. A mil is a measurement that equals one-thousandth of an inch, or 0.001 inch.

2. Consider the thickness of a human hair. One-thousandth of inch, or 0.001 inch, is almost the diameter of the human hair that resides on most of our heads. So a 1-mil-thick piece of plastic sheeting will be approximately the thickness of a human hair.

3. Note that the most common size in the thickness rating for plastic sheeting is 6 mil. This is 6-thousandths of an inch, or 0.006 inch.

4. Associate costs for plastic with the thickness of the plastic, since the sheets are composed of oil products. The thicker the plastic, generally the more expensive the cost.

5. Know that the thickness of the plastic sheeting, such as a 10-mil piece (0.010 inch), is not always be the best value for what the end application may be. Not all plastics are treated to withstand the sunlight and may quickly deteriorate under full exposure to the sun.

Tips & Warnings

• Many greenhouse plastics, while only 4 to 6 mils thick (0.004 to 0.006 inch), will last for many years due to sunlight-resistive additives placed in the plastic during the manufacturing process. Although these plastics may be more expensive, the durability is generally in excess of 4 consecutive years.
• Common plastic, untreated and with no sunlight protection, may last only one summer season if left exposed to the elements.

Resources

• Greenhouse plastic and films