The two most common types of insulation for commercial roof systems are Polyisocyanurate (Polyiso) and Expanded Polystyrene (EPS). Both are available in a variety of thicknesses and can be used in multiple applications. Polyiso is used in new construction designs more than EPS, though EPS still has it’s advantages.
Here is a quick comparison:
CATEGORY |
POLYISO |
EPS |
WINNER |
R-VALUE PER INCH: |
Higher |
Lower |
ISO |
COST PER SHEET: |
Higher |
Lower |
EPS |
FIRE RESISTANCE: |
UL class A rating |
Combustible |
ISO |
MOISTURE RESISTANCE: |
Lower |
Higher |
EPS |
EASE OF INSTALLATION (TAPERED): |
More difficult |
Easier |
EPS |
RIGIDITY: |
More rigid |
Less rigid |
ISO |
SYSTEM APPLICATIONS: |
Multiple |
Multiple |
TIE |
So which is best?
While the winner may not be so clear, both insulation types have their pros and cons. When it’s time for a new roof, contact your local roofing contractor to help you determine which insulation is best for your building and performance needs.
Polyiso
EPS