Single Layer Insulation Systems

What is R-Value?

Single Layer Fiberglass InsulationSingle Layer Insulation

R-Value is a measurement of the effectiveness of an insulator to retain or retard the loss of heat flow. The R-value is directly related to the fiber glass thickness. The thicker the fiberglass blanket the higher the R- value. All R-values listed are determined with the insulation uninstalled. Compression of the purlin install method will reduce the R-values listed.

Single Layer

Fiberglass insulation in steel buildings is commonly placed over the top purlin or girts before the exterior skin is secured with screws. The thickest system that can be achieved is a 6" R-19 system. Anything thicker than 6" will give your sheeting material a oil can or wave effect. If you want to achieve a higher R-Value than R-19 a Double Layer System is required.

Insulation Thickness


2.75" R-8
3" R-10
3.5" R-11
4" R-13
6" R-19