Hi all, So Im designing a floor system over piers. Part of the floor will be insulated and have living space above it. Part of it will be an exterior deck. For various reasons (including significant loads and super insulation) I'll be using 6x12 girders with 2x12 joists (both actual dimensions, rough saw hemlock) 16" oc center on top of them. The whole layout is very simple, its just one big rectangle, and I need to drop the level of the deck at least 6" below the level of the floor with the living space above. One way I could do this is to keep the girders the same dimension, but just change the dimension of the joists at the point where the exterior deck starts. So, the question is: are 2x6 joists 16" oc adequate for an exterior deck, assuming 60 psf live load? 2x4? 10' spans between girders. Any resources where I can figure out these calculations myself? Thanks, Dan

Here's one link of many. Google 'lumber span tables' for more results. Quickly looking at the link, it looks like your minimum would be 2X8, and even that might not be enough, depending upon species and grade of lumber. http://www.bearcreeklumber.com/employeepages/PDFs/wwpaWesternLumberSpanTables.pdf