I need designs that include wood joist 2 x 8’s and 2 x 10’s. Can you help?

I cannot find a floor-ceiling design or a roof-ceiling design that specify 2 x 8 wood joist. Why? Are there any roof-ceiling designs that specify 2 x 10’s?
Floor-Ceiling designs that specify 2 x 8’s (or 2 x 10’s) can be found using Product iQ^TM “Search with Specific Parameters”: Assembly type: Floor-Ceilings; Construct group: Wood Joist or Combination Wood and Steel Assemblies; Protection type: Gypsum Board; Keyword: “wood joists”. There are two 2 x 8 (L540 and L556) and many 2 x 10 designs. There are no roof-ceiling designs that specify dimensional lumber.