My contractor will be using locally milled spruce for my joist. 2x12 as indicated in my plans spanning 20 feet. I am not able to find a table that confirms that is OK. I think that it is Sitka spruce. What do you think.
Thanks
My Canadian span book lists spruce with pine and fir and says that "select structural" (the highest grade) will span 19'-6" for 40#/sf rooms (main living) and 21'-6" for upstairs sleeping rooms.
This span is determined by deflection (bounce) not strength. Thus you are OK if you either have the very straightest knot free boards possible or have full cut material (planed lumber is assumed in the tables). Your actual span is 19'.
And... If you want to insure a rock solid floor, let's say in the living room where you might have a dance, just place the joists 12" o/c.
This site:
http://www.contractorguides.com/baslumenforb.html
is giving you a sample of what you get when you buy their book/program.
But somewhere in there it says that sitka spruce is a class III or if it's "coast Sitka spruce" even a class IV wood.
Which means that if you have anybody's span tables that list class III or IV lumber you can look it up. I lost mine in a fire years ago.
John probably knows about a .pdf file with all kinds of span tables. And almost anybody from the western states would know more about sitka spruce than I do.