A framed wall has a 12-foot-high by 30-foot-long uninterrupted metal-lath cement-stucco field. The approved project specification follows UFGS 09 24 23 section 3.3 for control-joint layout. With no joints installed, which finding is correct?
- The 360-square-foot field must be divided into compliant panels; vertical joints creating three 12-by-10-foot panels can satisfy the stated size limits
- BNo joints are needed unless the substrate material changes
- CContinuous metal lath removes all panel-area limits
- DOne vertical joint creating two 12-by-15-foot panels satisfies the 144-square-foot maximum
Where to look it up
https://www.wbdg.org/FFC/DOD/UFGS/UFGS%2009%2024%2023.pdf
Why A is correct
UFGS 09 24 23 section 3.3 uses a 144-square-foot maximum panel area and an 18-foot maximum dimension; its layout note also addresses proportions. The original field is 12 × 30 = 360 square feet. Three 12-by-10-foot panels are each 120 square feet, have a longest dimension of 12 feet and a 1.2:1 ratio. Thus these size limits do not inherently require joints in both directions. Two 12-by-15-foot panels would each be 180 square feet. Actual drawings, joints at other conditions and section 3.4’s lath interruption requirements still apply. The cited federal guide is the expressly selected project specification, not a claim that its text is itself the IRC or a verified quotation of ASTM C1063. Source: https://www.wbdg.org/FFC/DOD/UFGS/UFGS%2009%2024%2023.pdf