An exterior load-bearing cold-formed steel wall carrying one floor and the roof is specified under the prescriptive tables of 2021 IRC R603.3.2. Its installed studs are marked 18-mil uncoated base thickness, and no alternate engineered design is supplied. What is the finding?
- AAccept because 18 mils automatically suits every bearing wall
- BAccept because coating thickness replaces the required base-steel thickness
- Do not accept the 18-mil studs under that prescriptive route; determine the required listed stud size and thickness for the actual conditions
- DReject only because interior partitions must use the same thickness as exterior bearing walls
Where to look it up
https://core-docs.s3.amazonaws.com/documents/asset/uploaded_file/3836/Lennox/3042182/2021_International_Residential_Code.pdf
Why C is correct
R603.3.2 selects exterior-wall stud size and thickness from its prescribed tables and actual design conditions; its permitted one-step thickness reductions have a 33-mil lower limit and specified sheathing conditions. That is not a rule that 33 mils suffices for every wall. The stated 18-mil product is not established as compliant under the selected prescriptive route. Verify the actual table selection or an approved alternative design; do not infer universal material-family boundaries or inevitable buckling solely from a thickness label. Source: https://core-docs.s3.amazonaws.com/documents/asset/uploaded_file/3836/Lennox/3042182/2021_International_Residential_Code.pdf