by Nathan Simmons


[1, 2]

Functional failure is when a component or system does not perform the intended function expected of it by the designer.[A] This means that the system or component is unable for some reason to serve its intended purpose. This does not mean that this failure will pose a threat to the health and safety of the occupants of the building. For example, let us say a house has settled a little bit. Because of this, a door is unable to close completely. This would count as a functional failure because the door (the system or component, in this case) is unable to serve its intended purpose (which in this case is being able to close). It does not directly threaten the safety and lives of the occupants, but it does show itself to be quite the defect and deviation from its main purpose.

Functional failure is a type of failure, meaning that it is a category of a difference between expected performance and actual performance. [A] Functional failure in building may be caused by a lack of maintenance. Keeping up general maintenance over time can prevent or functional failure caused by aging in general degenerating of material or degeneration due to overuse. Functional failure can also be caused due to lack of oversight by engineers over the workers during construction. [B] Liability can lie one the engineers, the workers, or even the owner for failure to maintain the component or system. [B]

[A]“Failure Mechanisms in Building Construction.” David H. Nicastro.The American Society of Civil Engineers. Print.