What allowable deflection should be specified for curtainwall applications?
• The main purpose of specifying an allowable stud deflection for curtainwall framing is actually for determining what is an acceptable deflection for the wall facing materials. A metal stud is ductile and therefore can perform at a wide range of deflections. Wall facing materials tend to be more brittle and thus have a more stringent maximum allowable deflection. The project architect or project specifications should note what the allowable deflection is for a given wall facing material.
• The main purpose of specifying an allowable stud deflection for curtainwall framing is actually for determining what is an acceptable deflection for the wall facing materials. A metal stud is ductile and therefore can perform at a wide range of deflections. Wall facing materials tend to be more brittle (Brick, Stucco or EIFS) and thus have a more stringent maximum allowable deflection. The project architect or project specifications should note what the allowable deflection is for a given wall facing material. For more information on Curtainwall Framing view our Curtain Wall Sizing Sheet.
