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 6×12 girders with 2×12 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 2×6 joists 16″ oc adequate for an exterior deck, assuming 60 psf live load? 2×4? 10′ spans between girders.
Any resources where I can figure out these calculations myself?
Thanks,
Dan
Replies
A source for span ratings:
I've used this in the past and they have a nice small book they used to send out-
http://www.cwc.ca
or
http://www.cwc.ca/Resources/E-Tools/etools.htm
Great Source
Wow, great source. Thanks. I see other sources only require designing for total loads of 50 psf. Using 2x6s, 16" oc, 50 psf, and No. 2 Hemlock, I get a maximim allowabe span of 9'1". Pretty close to the 9'8" I need. . .
I wonder if these calculations are for nominal dimensions, or actual . . . I'll be using real 2xs, and I wonder how that may change things.
Thanks.
danf
The numbers listed at that site and in their book are for dressed up lumber from the yard.
The grading is for the stamp ON the lumber. Since you have rough sawn you need a grade stamp to prove it.
My experience with inspection when trying to convince them of "slightly different" practice is that they will fall back on what they are familiar with...............in my case-usually dressed lumber. So, your 2"x12" would equal the listed sizes of a small 1-1/2 x 11-1/4.
But you can show them the material and certainly ask.
Best of luck on your project.