FB Blanket Pizza Oven Insulating Blanket
you have 50 sq feet. The density is 8 lbs /cu ft. the thickness is 1 inch (not actually specified but implied in the link)
Math time.
Determine how many cu ft you have (length X width X height)
length X width is 50 sq feet.
50 X (1/12) [covert from inches to feet] = 4.166 cu ft
Density X volume = weight (or maybe mass depending on proper use of units)
4.166 X 8 = 33.333 lbs for a roll
Figure another 4 pounds or so for a box to ship it in round it up to 40 pounds