▁m ason ry , ▁but ▁the ▁floor ▁system ▁was ▁fr amed ▁with ▁double ▁back - to - back ▁cold - formed ▁steel ▁li pped ▁channels . ▁According ▁to ▁Ch uck ▁Gre ene , ▁P . E ., ▁of ▁N olen ▁F ris a ▁Associ ates , ▁the ▁jo ists ▁were ▁ade qu ate ▁to ▁carry ▁the ▁initial ▁loads ▁and ▁sp ans , ▁based ▁on ▁current ▁analysis ▁techniques . ▁Gre ene ▁engine ered ▁a ▁recent ▁renov ation ▁to ▁the ▁structure ▁and ▁said ▁that ▁for ▁the ▁most ▁part , ▁the ▁jo ists ▁are ▁still ▁performing ▁well . ▁A ▁site ▁observation ▁during ▁this ▁renov ation ▁confirmed ▁that ▁" th ese ▁jo ists ▁from ▁the ▁' ro aring ▁tw ent ies ' ▁are ▁still ▁supporting ▁loads , ▁over ▁ 8 0 ▁years ▁later !" ▁ ▁In ▁the ▁ 1 9 4 0 s , ▁L ust ron ▁Hom es ▁built ▁and ▁sold ▁almost ▁ 2 5 0 0 ▁steel - fr amed ▁homes , ▁with ▁the ▁fr aming , ▁finish es , ▁cabin ets ▁and ▁furn iture ▁made ▁from ▁cold - formed ▁steel . ▁▁ ▁History ▁of ▁A IS I ▁design ▁standards ▁▁ ▁Design ▁standards ▁for ▁hot - rolled ▁steel ▁( see ▁struct ural ▁steel ) ▁were ▁adopted ▁in ▁ 1 9 3 0 s , ▁but ▁were ▁not ▁applicable ▁to ▁cold – formed ▁sections ▁because ▁of ▁their ▁relatively ▁thin ▁steel ▁walls ▁which ▁were ▁sus cept ible ▁to ▁bu ck ling . ▁Cold - formed ▁steel ▁members ▁maintain ▁a ▁constant ▁thick ness ▁around ▁their ▁cross - section