Where do I find decking design values?


The National Design Specification® (NDS®) Supplement tables list design values for 2x and larger decking. 

The American Lumber Standards Committee (ALSC) provides a Policy for Evaluation of Recommended Spans for Span Rated Decking Products. Here's more information on their website: http://www.alsc.org/untreated_spanrated_mod.htm

You will need to contact the specific grading agencies to obtain their span ratings for various species. A list of those agencies is on the ALSC website as well.

Lateral design values for lumber diaphragms and shear walls are available in Special Design Provisions for Wind and Seismic.

Also see the FAQ, "Where can I get span tables and span table information for lumber? Where can I get decking span tables?" for span information on decking.
Also see Tongue and Groove Roof Decking - WCD #2.
Also see Plank-And-Beam Framing for Residential Buildings - WCD #4.