Why is my raw foam sheet never the right size? For the same reason a wood 2×4 is never 2’’ by 4’’.
Let’s take the 2’’ plank for example. We call it a 48’’x108’’ plank with a thickness of 2’’.
But in reality it measures 2 1/8’’. Why ? Because, when we cut the foam with our equipment, the material is compressed and loses a little bit of its original thickness.
We also speck of a product by pounds (lbs), we say a : 2’’ 1.7lbs foam. This number indicates how ‘’soft’’ or dense the foam will be. The real measuring unit is pound per square feet ( lbs/ft²). This means that if I have a block of 12’’ x 12’’ x 12’’ it would weight 1.7 pound.