Thermal Bow explained by House of Doors - Roanoke, VA

WHAT IS IT?:

Thermal bow is a temporary condition that may occur in certain applications of metal door openings.  

WHAT CAUSES IT?:

The cause of thermal bow is differing temperatures on either side of an opening.  When steel doors experience a temperature difference between the door faces, the top and bottom of the lock edge of the door begin to distort either toward or away from the frame stop.  The larger the temperature difference, the more extreme the bowing.

WHAT HAPPENS?:

The bowing will cause the door opening to function poorly, or not at all.  As the door bows, clearances decrease.  Misalignment of the door and the strike jamb may cause the hardware to latch and unlatch with difficulty to the point of the lock binding.

Thermal bow is an industry wide issue that is referenced in the ANSI/SDI A250.8 Specifications for Standard Steel Doors and Frames as a general consideration.  

WHAT TO DO?:

Paint the doors a light color.  Dark colors such as black or brown increase the absorption of heat on the door face.  

Install awnings over the door opening to help block the sun.