They would be double 2x8 rim joists, under the long walls.
If the posts extend from footing to top plate of the wall with the floor beams hangered to the posts or supported on 2x blocks extending from footing to under the beams, then the posts would be braced by the wall sheathing.

Ok I need y'all's opinion ... I was going to go with 2x6 floor joists on 16 or 24 centers  I've read the tables . Clear span is slightly over 7 feet .   They just don't look beefy enough to me .   
Single story/no snow loads . 

[/URL]

#2 Doug Fir 2x6 can span about 9' and works but as many suggested to me:  deeper is better.

If insulation isn't an issue then 2x6 or 2x8 will work fine but code may require more.  I used 2x6 with a ~9' span and it's solid on 16" centers.  However I put support under the wood stove just to be certain and am building a new foundation under the outside wall so the cabin and floor is even more solid.  If I had to do it again I'd go with 2x10's or even 2x12's on 24" centers to span the distance (depending on loads etc).

Just my 2c

I'm with OlJarhead on this one.  I would do 2x10 so you have room to run pipe or whatever. 

Austin

Thanks for the input !   I think 10/12's may be slight over kill -  not too much to run between those joists - but extra insulation can't hurt !   May just go with 8's. But thanks for the extra input ...

I think you won't regret using 2x10's or even 2x12's and depending on the spans you may save money.  For example the 2x6 DF#2's can span 9' but to get any reasonable loading you need 16" centers (which is what I did).  However, if you overbuild your walls (which I did by using 2x6's on 16" centers and going 10' tall) you add more weight than really should be carried by the 2x6's IMHO so, if like me and you do that, you end up sticking a new foundation under the outer walls.

Better bet is to span the 14' (for my cabin) and go with deeper joists - I did a quick search and this is what I found using 16" centers:
2x6 DF#2's max span is 9'9" with 40lbs live load (10lbs dead) ($9.47ea@HD for 14') (cost $180 for 19 that will span 9'9" and have nearly 22" cantilever that you'd have to brace)
2x8 DF#2's max span is 12'5" ($13.92 for 16') (cost $265 to span 12'5" with only about 8-10" cantilver -- no bracing required really)
2x10 DF#2's max span is 15'2" ($19.69 for 16') (Cost $375 to span the entire 14' end to end so no cantilever at all and a much better floor)
2x12 DF#2's max span is 17'7" ($24.49 for 16') (cost $465 but way over built if you ask me)
2x12 DF#2's max span is 14'4" is using 24" centers ($318 to span entire 14' with a much stronger floor that can also take R38 insulation)

I used: http://www.awc.org/calculators/span/calc/timbercalcstyle.asp

So looking at that (and I wish I'd done this before building my cabin) you can spend the extra $138 to get 2x12 joists on 24" centers but in return get twice the insulation out of the deal, no cantilever that might cause stress, no worries about needing to brace the cantilever or adding support when you put in a heavy wood stove etc and it would be to code (or better).

All in all I have to say had I done this math more seriously when I was build I WOULD have gone with 2x12's right off.  And considering the span I might have even made my cabin a little wider.

Just something to  ponder

Note:  I used 16' lengths only because that's what they had online.  I've purchased plenty of 14 footers so their cost would be cheaper (so you might get away with even less dollars in the end).  Also I based my calcs on my floor which is 14' x 24'

OK one more post  

I missed the 7' span somehow.  Sorry. 

So looking at the pic above it appears you have beams running the width every 7'OC?  If so and you're laying the joists across those then 2x6 will span just fine.  Won't get the insulation of a deeper floor but if you have no snow loads then I'm assuming it isn't likely to ever get very cold and my 2x6 R19 floor is just fine in -20F weather.

WOW - Im so behind posting anything about this build ....
Coming today !

Where did I leave off - foundation - went with 2x6 - wish i had done 2x8 - little mushy



Used my floor to build my own rafter/trusses...

[img]https://i1230.photobucket.com/albums/ee491/Tdelaurier/IMG_0621.jpg[img]

Lots of reason i built the trusses the way I did... They are up and strong

So that was I guess DEC 2014 - FEB 2015..

Worked a little be when I got home from work and on weekends as I had left over cash each month.

March and April 2015
Slowly getting more done - WITH zero help.


My 18 year old Maine Coon - constant companion.

April was a good month.  Got tons done - Found some extra cash to spend.


And then it rained for the entire month of May. Record breaking levels ever recorded in May in Texas.  Sorry Cali.

June - out of school - Im a teacher ----- More done



I hate ladders and roofs - I might be outta my skill set getting the metal roof on myself....

Looks good!  Sure feels good to step back and see how far you've come doesn't it. 
What part of central TX are you building in?  I'm building out near Harper.

I like the trusses, I've been thinking of how to do it prescriptively, and I think it might be easier if anyone follows this later. The peak gusset and kingpost could be done just like these. If the bottom chord/rafter tie is then lapped across the faces of the rafters and kingpost the nailing requirement in the heeljoint table at the end of the rafter tables in the codebook work. Read the adjustment for raised ties, it'll increase the nail count by a few. That should make that connection easier and right out of the book. The ridge gusset is also right out of the code. The birdsmouths would probably need to be notches to pass inspection, but most of us would have deeper rafters so this wouldn't be a problem.

Uninspected, one way to reverse engineer the code rafter tie connection and then use plywood side plates to build it like thomasd, is to use the awc.org connections calc. Plug in the code connection to find the strength they want, then set the calc up with plywood sideplates and find the correct nail count doing it that way. Remember you'll have that connection requirement into both members. 

Yep what DonP said....

This is the biggest thing Ive ever built.... Im no stranger to hammers and tool - I build sets for the theatre..  But this is a whole new thing for me...I did a years worth of reading before I even broke ground...

I originally built those trusses that way because first of all I wanted a higher center ceiling and I could get 12 footers home on my car roof easier - and finding a flat/straight 16 footer was almost impossible...  Im pretty sure they are super strong with all the wood glue and nails i used ... I kinda missed a step on the ladder one day and ended up hanging from the bottom chord ... Im 260lbs and that sucker didnt even flex...

What I didnt take into account was the heel plate junction at the top plate and how Id eventually hang drywall from it up to the ceiling and insulate it and provide a path for air from the soffit ...  Ive worked out a fix - but it vexed me for a long time ... Ill have to take some pics

TD

Updates - Sorry for the slowness in posting pics
Update - Moved in this March and am slowly doing  trim work
Here are some pics - Roof was started last summer

Tin was cheaper than shingles - and probably quicker..








Strips of Pine and Oak glued and brad nailed to each other  - came out ok !!   Lots of sanding
Tried to be creative and stain a faux rug at front door - its currently covered by a real rug



Solar battery box - currently  - 6 - 6volt 220 amp hour batteries - powers all lights and ceiling fans



Old pine floors from a tear down in Austin - got a good deal on 2 truck loads  - ReStore at old location downtown....  LOTS AND LOTS of oil Base poly - damn that stuff is pricey ....

Looking good!  I really like your siding and paint combination.  Is the corrugated steel at the bottom purely ornamental?  Where I will be building you don't want exposed plywood or T1-11 the bottom few feet as the porcupines like to eat the glue.

I quess its both - it covers the tar paper and plywood beneath that  - the eaves are so wide that its doesnt see much rain unless its blowing - It was also a money saver cause i didnt need whole sheets of t11 I could use the remainder for the eaves and the Tin was free .    I like the look as well  Thanks