Keeping pace with advances in Denver sign technology, Greyhawk Signs has been certified by Underwriters Laboratories Inc. (UL). This highly sought-after certification demonstrates Greyhawk’s leadership in setting the bar even higher in quality and more importantly the safety of our commercial signs.  

The UL certification involves a rigorous training and onboarding processes to ensure all products produced by Greyhawk Signs are acceptable under UL standard 48. In the sign industry, UL 48 is the highest known standard for quality and proper construction methods. Greyhawk Signs will only use components that are carefully chosen from UL certified devices and materials.

UL was established in 1894 and is the forerunner in product safety and standards certification. 

Greyhawk Signs manufactures, installs and repairs channel letter signs, lighted sign cabinets and dimensional letters for outdoor business signs as well as interior lobbies and offices. Surveying and permitting are also provided. Contact Greyhawk Signs in Denver at 303-946-0124 or at