Murphy’s Law and Heel Height

In the field things don’t always turn out as clean and easy as we would like. Unfortunately, this happens more often than anybody may want. When trusses don’t come together in a design and the heel height is reduced, this in turn reduces the downward and uplift loads that can be carried.


To clarify, the heel height is defined as the distance from the bearing seat of the hangar to the upper most nail, plus an additional 3/8 for edge distance. Specific heel heights are required for each connector, with a specified fastener schedule, in order to achieve the designed downward and uplift capacity. When this height is not properly achieved, the required fastening schedule cannot be achieved, and reduced downward and uplift loads must be calculated to ensure the design loads for the connection can still be achieved.


USP has recently published a Technical Bulletin which lists common hangars and their reduced loads based upon reduced heel heights. This “cheat sheet” is a valuable tool and can be downloaded at  . 



 This page last modified on 1/27/2012