Calculate the number of underlayment rolls needed based on roof area and roll dimensions. Underlayment provides secondary weather protection.
Enter your values below
Total roof area in square feet.
Width of the underlayment roll (typically 3 ft for synthetic, 36" for felt).
Length of each roll.
How this calculator works
Number of rolls equals roof area divided by the coverage per roll (roll width times roll length).
Common questions about this calculator
