The "thickest" vinyl siding on the market today is made by Alcoa and is .055 mls thick.  Duraplank plastic siding is next at .054 mls thick.  Builders grade plastic siding is typically .042-.044 mls thick.  The difference, you may ask?  Less than a sheet of paper in thickness. HardiePlank® fiber cement siding is 5 1/2 [...]